During air injection into an oil reservoir,an oxidation reaction generates some heat to raise the reservoir temperature.When the reservoir temperature reaches an ignition temperature,spontaneous ignition occurs.There ...During air injection into an oil reservoir,an oxidation reaction generates some heat to raise the reservoir temperature.When the reservoir temperature reaches an ignition temperature,spontaneous ignition occurs.There is a time delay from the injection to ignition.There are mixed results regarding the feasibility of spontaneous ignition in real-field projects and in laboratory experiments.No analytical model is available in the literature to estimate the oxidation time required to reach spontaneous ignition with heat loss.This paper discusses the feasibility of spontaneous ignition from theoretical points and experimental and field project observations.An analytical model considering heat loss is proposed.Analytical models with and without heat loss investigate the factors that affect spontaneous ignition.Based on the discussion and investigations,we find that it is more difficult for spontaneous ignition to occur in laboratory experiments than in oil reservoirs;spontaneous ignition is strongly affected by the initial reservoir temperature,oil activity,and heat loss;spontaneous ignition is only possible when the initial reservoir temperature is high,the oil oxidation rate is high,and the heat loss is low.展开更多
Exploding foil initiator(EFI)is a kind of advanced device for initiating explosives,but its function is unstable when it comes to directly igniting pyrotechnics.To solve the problem,this research aims to reveal the ig...Exploding foil initiator(EFI)is a kind of advanced device for initiating explosives,but its function is unstable when it comes to directly igniting pyrotechnics.To solve the problem,this research aims to reveal the ignition mechanism of EFIs directly igniting pyrotechnics.An oscilloscope,a photon Doppler velocimetry,and a plasma spectrum measurement system were employed to obtain information of electric characteristics,impact pressure,and plasma temperature.The results of the electric characteristics and the impact pressure were inconsistent with ignition results.The only thing that the ignition success tests had in common was that their plasma all had a relatively long period of high-temperature duration(HTD).It eventually concludes that the ignition mechanism in this research is the microconvection heat transfer rather than the shock initiation,which differs from that of exploding foil initiators detonating explosives.Furthermore,the methods for evaluating the ignition success of semiconductor bridge initiators are not entirely applicable to the tests mentioned in this paper.The HTD is the critical parameter for judging the ignition success,and it is influenced by two factors:the late time discharge and the energy of the electric explosion.The longer time of the late time discharge and the more energy of the electric explosion,the easier it is to expand the HTD,which improves the probability of the ignition success.展开更多
The arc ignition system based on charring polymers has advantages of simple structure,low ignition power consumption and multiple ignitions,which bringing it broadly application prospect in hybrid propulsion system of...The arc ignition system based on charring polymers has advantages of simple structure,low ignition power consumption and multiple ignitions,which bringing it broadly application prospect in hybrid propulsion system of micro/nano satellite.However,charring polymers alone need a relatively high input voltage to achieve pyrolysis and ignition,which increases the burden and cost of the power system of micro/nano satellite in practical application.Adding conductive substance into charring polymers can effectively decrease the conducting voltage which can realize low voltage and low power consumption repeated ignition of arc ignition system.In this paper,a charring conductive polymer ignition grain with a cavity geometry in precombustion chamber,which is composed of PLA and multiwall carbon nanotubes(MWCNT)was proposed.The detailed ignition processes were analyzed and two different ignition mechanisms in the cavity of charring conductive polymers were revealed.The ignition characteristics of charring conductive polymers were also investigated at different input voltages,ignition grain structures,ignition locations and injection schemes in a visual ignition combustor.The results demonstrated that the ignition delay and external energy required for ignition were inversely correlated with the voltages applied to ignition grain.Moreover,the incremental depth of cavity shortened the ignition delay and external energy required for ignition while accelerated the propagation of flame.As the depth of cavity increased from 2 to 6 mm(at 50 V),the time of flame propagating out of ignition grain changed from 235.6 to 108 ms,and values of mean ignition delay time and mean external energy required for ignition decreased from 462.8 to 320 ms and 16.2 to 10.75 J,respectively.The rear side of the cavity was the ideal ignition position which had a shorter ignition delay and a faster flame propagation speed in comparison to other ignition positions.Compared to direct injection scheme,swirling injection provided a more favorable flow field environment in the cavity,which was beneficial to ignition and initial flame propagation,but the ignition position needed to be away from the outlet of swirling injector.At last,the repeated ignition characteristic of charring conductive polymers was also investigated.The ignition delay time and external energy required for ignition decreased with repeated ignition times but the variation was decreasing gradually.展开更多
Incorporating aluminum metal-organic frameworks(Al-MOFs)as energetic additives for solid fuels presents a promising avenue for enhancing combustion performance.This study explores the potential benefits of Al-MOF(MIL-...Incorporating aluminum metal-organic frameworks(Al-MOFs)as energetic additives for solid fuels presents a promising avenue for enhancing combustion performance.This study explores the potential benefits of Al-MOF(MIL-53(Al))energetic additive on the combustion performance of hydroxyl-terminated polybutadiene(HTPB)fuel.The HTPB-MOF fuel samples were manufactured using the vacuum-casting technique,followed by a comprehensive evaluation of their ignition and combustion properties using an opposed flow burner(OFB)setup utilizing gaseous oxygen as an oxidizer.To gauge the effectiveness of Al-MOFs as fuel additives,their impact is compared with that of nano-aluminum(nAl),another traditional additive in HTPB fuel.The results indicate that the addition of 15%(mass fraction)nAl into HTPB resulted in the shortest ignition delay time(136 ms),demonstrating improved ignition performance compared to pure HTPB(273 ms).The incorporation of Al-MOF in HTPB also reduced ignition delay times to 227 ms and 189 ms,respectively.Moreover,under high oxidizer mass flux conditions(79—81 kg/(m^(2)s)),HTPB fuel with 15%nAl exhibited a substantial 83.2%increase in regression rate compared to the baseline HTPB fuel,highlighting the positive influence of nAl on combustion behavior.In contrast,HTPB-MOF with a 15%Al-MOF additive showed a 32.7%increase in regression rate compared to pure HTPB.These results suggest that HTPB-nAl outperforms HTPB-MOF in terms of regression rates,indicating a more vigorous and rapid burning behavior.展开更多
Booming low-power electric propulsion systems require 1–2 A hollow cathodes.Such cathodes are expected to go through more frequent ignitions in the low orbit,but the impact of cyclic ignitions on such 1–2 A barium t...Booming low-power electric propulsion systems require 1–2 A hollow cathodes.Such cathodes are expected to go through more frequent ignitions in the low orbit,but the impact of cyclic ignitions on such 1–2 A barium tungsten hollow cathodes with a heater was not clear.In this study,a 12,638-cyclic ignition test and a 6,000-hour-long life test on two identical cathodes were carried out.The discharge voltage of the cathode and the erosion of the orifice after cyclic ignition were all larger than that of the cathode after stable operation.This indicated that the impact of cycle ignition on the discharge performance of a low current BaO-W cathode with a heater was higher than that of stable operation.The results of the ion energy distribution function measured during the ignition period indicated that the main reason for the orifice expansion was ion bombardment.Therefore,it was necessary to pay attention to the number of ignitions for the lifetime of this kind of cathode.展开更多
Understanding the response of solid combustibles under high radiant fluxes is critical in predicting the thermal damage from extreme scenarios.Unlike the more moderate radiant fluxes in conventional hydrocarbon fires,...Understanding the response of solid combustibles under high radiant fluxes is critical in predicting the thermal damage from extreme scenarios.Unlike the more moderate radiant fluxes in conventional hydrocarbon fires,extreme events such as strong explosion,concentrated sunlight and directed energy can generate dynamic radiant fluxes at the MW/m^(2) level,creating a unique threat to materials.This study investigates the pyrolysis and spontaneous ignition behaviors of corrugated cardboard by using both experimental and numerical methods,under 10-cm dynamic high radiant fluxes ranging from 0.2 to 1.25 MW/m^(2) for 10 s.The spontaneous ignition process at dynamic high radiant fluxes was recorded and quantified.Two ignition modes were found at the critical radiant flux of 0.4 MW/m^(2),namely hot-gas spontaneous ignition and hot-residue piloted ignition.The latter is not the focus of this paper due to its extremely small probability of occurrence.The research reveals that the increase in flux intensity induces shorter delay times for both pyrolysis and ignition,lower ignition energy density,along with a corresponding rise in the critical mass flux and surface temperature at ignition moment.The simulation results are generally aligned with the experimental findings,despite some divergences may be attributed to model simplifications and parameter assumptions.The work contributes to a deeper insight into material behavior under extreme radiation,with valuable implications for fire safety and hazard assessment.展开更多
5-amino-4-nitrobenzo[1,2-c:3,4-c']bis([1,2,5]oxadiazole)1,6-dioxide(CL-18)exhibits significant potential as an initiating explosive.However,its current synthesis process remains non-scalable due to low yields and ...5-amino-4-nitrobenzo[1,2-c:3,4-c']bis([1,2,5]oxadiazole)1,6-dioxide(CL-18)exhibits significant potential as an initiating explosive.However,its current synthesis process remains non-scalable due to low yields and safety risks.In this study,we have developed a simple and safe synthetic route for CL-18.It was synthesized from 3,5-dihaloanisole in a four-step reaction with an overall yield exceeding 60%,surpassing all reported yields in the literature.Subsequently,recrystallization of CL-18 was successfully achieved by carefully selecting appropriate solvents and antisolvents to reduce its mechanical sensitivity.Ultimately,when DMF-ethanol was employed as the recrystallization solvent system,satisfactory product yield(>90%)and reduced mechanical sensitivity(IS=15 J;FS=216 N)were obtained.Additionally,CL-18 is derived from the rearrangement of oxygen atoms on i-CL-18 furoxan,and a comparative analysis of their physicochemical properties was conducted.The thermal stability of both compounds is similar,with onset decomposition temperatures recorded at 186 and 182℃respectively.Similarly,they exhibit 5 s breaking point temperatures of 236 and 237℃.Additionally,we present novel insights into the positional-isomerization-laser-ignition performance of CL-18 and its isomer i-CL-18 using laser irradiation for the first time.Remarkably,our findings demonstrate that i-CL-18 exhibits enhanced laser sensitivity,as it can be directly ignited by a 1064 nm wavelength laser,whereas CL-18 lacks this characteristic.展开更多
Energetic Semiconductor bridge(ESCB)based on reactive multilayered films(RMFs)has a promising application in the miniature and intelligence of initiator and pyrotechnics device.Understanding the ignition enhancement m...Energetic Semiconductor bridge(ESCB)based on reactive multilayered films(RMFs)has a promising application in the miniature and intelligence of initiator and pyrotechnics device.Understanding the ignition enhancement mechanism of RMFs on semiconductor bridge(SCB)during the ignition process is crucial for the engineering and practical application of advanced initiator and pyrotechnics devices.In this study,a one-dimensional(1D)gas-solid two-phase flow ignition model was established to study the ignition process of ESCB to charge particles based on the reactivity of Al/MoO_(3) RMFs.In order to fully consider the coupled exothermic between the RMFs and the SCB plasma during the ignition process,the heat release of chemical reaction in RMFs was used as an internal heat source in this model.It is found that the exothermal reaction in RMFs improved the ignition performance of SCB.In the process of plasma rapid condensation with heat release,the product of RMFs enhanced the heat transfer process between the gas phase and the solid charge particle,which accelerated the expansion of hot plasma,and heated the solid charge particle as well as gas phase region with low temperature.In addition,it made up for pressure loss in the gas phase.During the plasma dissipation process,the exothermal chemical reaction in RMFs acted as the main heating source to heat the charge particle,making the surface temperature of the charge particle,gas pressure,and gas temperature rise continuously.This result may yield significant advantages in providing a universal ignition model for miniaturized ignition devices.展开更多
In order to address the issue of gold mixing caused by the Kelvin-Helmholtz instability(KHI)in the double-cone ignition(DCI)scheme,we investigate the growth rate of the KHI at the bi-interface of the DCI scheme after ...In order to address the issue of gold mixing caused by the Kelvin-Helmholtz instability(KHI)in the double-cone ignition(DCI)scheme,we investigate the growth rate of the KHI at the bi-interface of the DCI scheme after applying a coating.This is done by solving the hydrodynamic equations for an ideal incompressible fluid using linear theory.Ultimately,it is discovered that applying a coating with a thickness slightly above h=0.5(λ+10μm)and a density somewhat lower than that of the target layer can effectively reduce the growth rate of interfacial KHI.This work provides theoretical references for studying the bi-interface KHI in the DCI scheme.展开更多
In the double-cone ignition schemes(DCIS), the deuterium–tritium target shell is ablated and compressed by a highpower nanosecond laser in Au-cones to generate plasmas. Under the actions of spherically symmetric comp...In the double-cone ignition schemes(DCIS), the deuterium–tritium target shell is ablated and compressed by a highpower nanosecond laser in Au-cones to generate plasmas. Under the actions of spherically symmetric compression and acceleration along the Au cone, they will be ejected out of the cone mouth and collide with each other. The plasmas experience conversion from kinetic energy to internal energy at the vertex of the geometric center of two Au cones that are symmetric to each other, because of which high-density fusion plasmas are preheated. This key physical process has undergone experimental verification on the Shenguang-II upgraded facility in China. Apparently, the improvement and optimization of the velocity of plasmas in hypersonic jet flow at the cone mouth are crucial for the success of the DCIS. In the DCIR7 experiment of the Shenguang-II upgraded facility, a velocity yield of approximately 130–260 km/s was achieved for the plasmas at the cone mouth, with a result of nearly 300 km/s based on numerical simulation. In this paper, theoretical analysis is performed as regards the process, in which target shells are ablated and compressed by laser to generate highvelocity plasmas ejected through jet flow. Based on this analysis, the formula for the velocity of plasmas in supersonic jet flow at the cone mouth is proposed. This study also provides measures that are more effective for improving the kinetic energy of plasmas and optimizing energy conversion efficiency, which can serve as theoretical references for the adjustment and optimization of processes in subsequent experiments.展开更多
We developed a monochromatic crystal backlight imaging system for the double-cone ignition(DCI) scheme, employing a spherically bent quartz crystal. This system was used to measure the spatial distribution and tempora...We developed a monochromatic crystal backlight imaging system for the double-cone ignition(DCI) scheme, employing a spherically bent quartz crystal. This system was used to measure the spatial distribution and temporal evolution of the head-on colliding plasma from the two compressing cones in the DCI experiments. The influence of laser parameters on the x-ray backlighter intensity and spatial resolution of the imaging system was investigated. The imaging system had a spatial resolution of 10 μm when employing a CCD detector. Experiments demonstrated that the system can obtain time-resolved radiographic images with high quality, enabling the precise measurement of the shape, size, and density distribution of the plasma.展开更多
Investigating the ignition response of nitrate ester plasticized polyether(NEPE) propellant under dynamic extrusion loading is of great significant at least for two cases. Firstly, it helps to understand the mechanism...Investigating the ignition response of nitrate ester plasticized polyether(NEPE) propellant under dynamic extrusion loading is of great significant at least for two cases. Firstly, it helps to understand the mechanism and conditions of unwanted ignition inside charged propellant under accident stimulus.Secondly, evaluates the risk of a shell crevice in a solid rocket motor(SRM) under a falling or overturning scene. In the present study, an innovative visual crevice extrusion experiment is designed using a dropweight apparatus. The dynamic responses of NEPE propellant during extrusion loading, including compaction and compression, rapid shear flow into the crevice, stress concentration, and ignition reaction, have been firstly observed using a high-performance high-speed camera. The ignition reaction is observed in the triangular region of the NEPE propellant sample above the crevice when the drop weight velocity was 1.90 m/s. Based on the user material subroutine interface UMAT provided by finite element software LS-DYNA, a viscoelastic-plastic model and dual ignition criterion related to plastic shear dissipation are developed and applied to the local ignition response analysis under crevice extrusion conditions. The stress concentration occurs in the crevice location of the propellant sample, the shear stress is relatively large, the effective plastic work is relatively large, and the ignition reaction is easy to occur. When the sample thickness decreases from 5 mm to 2.5 mm, the shear stress increases from 22.3 MPa to 28.6 MPa, the critical value of effective plastic work required for ignition is shortened from 1280 μs to 730 μs, and the triangular area is easily triggering an ignition reaction. The propellant sample with a small thickness is more likely to stress concentration, resulting in large shear stress and effective work, triggering an ignition reaction.展开更多
Explosion-electricity coupling(EEC) is a technical method to induce electric energy into the plasma material produced by explosion to improve the output of explosion.Exploding foil initiator(EFI) which could produce p...Explosion-electricity coupling(EEC) is a technical method to induce electric energy into the plasma material produced by explosion to improve the output of explosion.Exploding foil initiator(EFI) which could produce plasma during electric explosion can serve as a good carrier for studying the EEC.To investigate the enhancement ability and mechanism of EEC in EFI ignition performance,a kind of EFI chips which could realize the EEC effect was designed and fabricated to observe the characteristics of current and voltage,flyer and plasma temperature during Boron Potassium Nitrate(BPN) ignition of the EFI.It was found that the EEC could enhance EFI ignition in terms of energy utilization,ignition contact surface,and high-temperature sustainability of plasma:firstly,the EEC prolonged the late time discharge(LTD) phase of the electric explosion,making the energy of capacitor effectively utilized;secondly,the EEC could create a larger area of ignition contact surface;last of all,the EEC effect enhanced its hightemperature sustainability by sustaining continuous energy input to plasma.It also was found that the ignition voltage of BPN could be reduced by nearly 600 V under the condition of 0.4 μF capacitance.The research has successfully combined EEC with EFI,revealing the behavioral characteristics of EEC and demonstrating its effective enhancement of EFI ignition.It introduces a new approach to improving EFI output,which is conducive to low-energy ignition of EFI,and expected to take the ignition technology of EFI to a new level.展开更多
A model for fast electron-driven high-density plasma is proposed to describe the effect of injected fast electrons on the temperature and inner pressure of the plasma in the fast heating process of the double-cone ign...A model for fast electron-driven high-density plasma is proposed to describe the effect of injected fast electrons on the temperature and inner pressure of the plasma in the fast heating process of the double-cone ignition(DCI)scheme.Due to the collision of the two low-density plasmas,the density and volume of the high-density plasma vary.Therefore,the ignition temperature and energy requirement of the high-density plasma vary at different moments,and the required energy for hot electrons to heat the plasma also changes.In practical experiments,the energy input of hot electrons needs to be considered.To reduce the energy input of hot electrons,the optimal moment and the shortest time for injecting hot electrons with minimum energy are analyzed.In this paper,it is proposed to inject hot electrons for a short time to heat the high-density plasma to a relatively high temperature.Then,the alpha particles with the high heating rate and PdV work heat the plasma to the ignition temperature,further reducing the energy required to inject hot electrons.The study of the injection time of fast electrons can reduce the energy requirement of fast electrons for the high-density plasma and increase the probability of successful ignition of the high-density plasma.展开更多
Aim To present a new kind of rapid ignition tube for igniting the propellant of heavy calibre gun uniformly and synchronistically so as to decrease the pressure wave. Methods Firing tests were carried out. Relationsh...Aim To present a new kind of rapid ignition tube for igniting the propellant of heavy calibre gun uniformly and synchronistically so as to decrease the pressure wave. Methods Firing tests were carried out. Relationships between pressure and time ( p t curves) at different positions of the tube are measured. The mode of igniter tube of quasi one dimensional two phase flow is given. Results\ The test results indicate that the speed of ignition front in the ignition tube is very fast and the pressure distribution within the igniter tube is uniform. Results of experiments and numerical calculations of the combustion in the igniter tube are in reasonable agreement. Conclusion\ The new igniter tubes have a very high velocity of propagation of ignition stimuli and can ignite the propellant bed synchronistically.展开更多
An engine cyclic variation model has been built by using the residual gas temperature for the n th cycle as the input of the model, through constant pressure intake process, adiabatic compression process, constan...An engine cyclic variation model has been built by using the residual gas temperature for the n th cycle as the input of the model, through constant pressure intake process, adiabatic compression process, constant volume combustion process, adiabatic expansion process, adiabatic blow down process and constant pressure exhaust process to approximate the thermodynamic processes in the cylinder, finally the residual gas temperature for the ( n+1) th cycle can be estimated. Because of the adding of engine operating parameters such as engine speed, spark advance, equivalence ratio, intake air pressure, intake air temperature to the model, effects of these parameters on cyclic variation can be estimated quantitatively. Since residual gas temperature fluctuation between cycles reflects the circumstances of engine cyclic variation, parameters to which residual gas temperature is sensitive are most likely used as the means to control cyclic variation. Model simulation shows that for the nearly stiochiometric mixture, cyclic variation is not obvious or even quite stable, but for the lean mixture, under the circumstances of partial load and larger spark advances, engine cyclic variations occur chaotically or with bifurcation.展开更多
At present, aero-engines face a major need to widen the ignition envelope. In order to provide a technical support to expand the high altitude ignition envelope of aero-engines, in this article we propose a novel igni...At present, aero-engines face a major need to widen the ignition envelope. In order to provide a technical support to expand the high altitude ignition envelope of aero-engines, in this article we propose a novel ignition technology, i.e., "precombustion plasma jet ignition technology". In this paper, we also design a pre-combustion plasma jet igniter. Its discharge characteristics, jet characteristics, and ignition effects are studied. The results show that increasing the equivalent ratio of jet gas can enhance the discharge stability and increase the duty cycle. At the same time, it can reduce working power and energy consumption. The increase of equivalent ratio in jet gas can enhance the length and ignition area of plasma jet.In the process of ignition, the pre-combustion plasma jet igniter has obvious advantages, suchn as shortening the ignition delay time and enlarging the ignition boundary. When the airflow velocity is 39.11 m/s and the inlet air temperature is80℃, compared with the spark igniter and the air plasma jet igniter, the pre-combustion plasma jet igniter has an ignition boundary that is expanded by 319.8% and 55.7% respectively.展开更多
Reactive material projectiles can be an extremely efficient lethality enhancement technology that incorporates the defeat mechanisms of chemical energy and kinetic energy.This paper presents such a research on the enh...Reactive material projectiles can be an extremely efficient lethality enhancement technology that incorporates the defeat mechanisms of chemical energy and kinetic energy.This paper presents such a research on the enhanced ignition behavior of reactive material projectiles impacting a fuel-filled tank.Firstly,the ignition process description of the fuel-filled tank impacted by inert metal and reactive material projectiles is presented.Secondly,ballistic impact experiments are performed to investigate the ignition effects of the fuel-filled tank impacted by reactive material versus tungsten alloy projectiles with mass matched.The fuel tank used for the experiments is a cylindrical steel casing structure filled with aviation kerosene and sealed with aluminum cover plates on both ends using screw bolts.The experimental results indicate that,compared with impacts from tungsten alloy projectiles,there is dramatically enhanced structural damage to the fuel-filled tank and an enhanced ignition effect caused by reactive material projectile impacts.Finally,an analytical model is developed,by which the effects of the aluminum cover plate thickness on critical structural failure energy of the fuel-filled tank and the total energy of the reactive material projectile deposited into the fuel-filled tank are discussed.The analysis shows a good agreement with the experiments.展开更多
Most, if not all longwall gob areas accumulate explosive methane-air mixtures that pose a deadly hazard to miners. Numerous mine explosions have originated from explosive gas zones(EGZs) in the longwall gob. Since 201...Most, if not all longwall gob areas accumulate explosive methane-air mixtures that pose a deadly hazard to miners. Numerous mine explosions have originated from explosive gas zones(EGZs) in the longwall gob. Since 2010, researchers at the Colorado School of Mines(CSM) have studied EGZ formation in longwall gobs under two long-term research projects funded by the National Institute for Occupational Safety and Health. Researchers used computational fluid dynamics along with in-mine measurements. For the first time, they demonstrated that EGZs form along the fringe areas between the methane-rich atmospheres and the fresh air ventilated areas along the working face and present an explosion and fire hazard to mine workers. In this study, researchers found that, for progressively sealed gobs, a targeted injection of nitrogen from the headgate and tailgate, along with a back return ventilation arrangement, will create a dynamic seal of nitrogen that effectively separates the methane zone from the face air and eliminates the EGZs to prevent explosions. Using this form of nitrogen injection to create dynamic seals should be a consideration for all longwall operators.展开更多
Direct current plasma torches have been applied to generate unique sources of thermal energy in many industrial applications. Nevertheless, the successful ignition of a plasma torch is the key process to generate the ...Direct current plasma torches have been applied to generate unique sources of thermal energy in many industrial applications. Nevertheless, the successful ignition of a plasma torch is the key process to generate the unique source （plasma jet）. However, there has been tittle study on the underlying mechanism of this key process. A thorough understanding of the ignition process of a plasma torch will be helpful for optimizing the design of the plasma torch structure and selection of the ignition parameters to prolong the service life of the ignition module. Thus, in this paper, the ignition process of a segmented plasma torch （SPT） is theoretically and experimentally modeled and analyzed. Corresponding electrical models of different stages of the ignition process axe set up and used to derive the electrical parameters, e.g. the variations of the arc voltage and arc current between the cathode and anode. In addition, the experiments with different ignition parameters on a home-made SPT have been conducted. At the same time, the variations of the arc voltage and arc current have been measured, and used to verify the ones derived in theory and to determine the optimal ignition parameters for a particular SPT.展开更多
基金supported by the National Natural Science Foundation of China (No.51974334)Hainan Province Science and Technology Special Fund (ZDYF2022SHFZ107)local efficient reform and development funds for personnel training projects supported by the central government,Heilongjiang Postdoctoral Scientific Research Fund (LBH-Q21012)。
文摘During air injection into an oil reservoir,an oxidation reaction generates some heat to raise the reservoir temperature.When the reservoir temperature reaches an ignition temperature,spontaneous ignition occurs.There is a time delay from the injection to ignition.There are mixed results regarding the feasibility of spontaneous ignition in real-field projects and in laboratory experiments.No analytical model is available in the literature to estimate the oxidation time required to reach spontaneous ignition with heat loss.This paper discusses the feasibility of spontaneous ignition from theoretical points and experimental and field project observations.An analytical model considering heat loss is proposed.Analytical models with and without heat loss investigate the factors that affect spontaneous ignition.Based on the discussion and investigations,we find that it is more difficult for spontaneous ignition to occur in laboratory experiments than in oil reservoirs;spontaneous ignition is strongly affected by the initial reservoir temperature,oil activity,and heat loss;spontaneous ignition is only possible when the initial reservoir temperature is high,the oil oxidation rate is high,and the heat loss is low.
文摘Exploding foil initiator(EFI)is a kind of advanced device for initiating explosives,but its function is unstable when it comes to directly igniting pyrotechnics.To solve the problem,this research aims to reveal the ignition mechanism of EFIs directly igniting pyrotechnics.An oscilloscope,a photon Doppler velocimetry,and a plasma spectrum measurement system were employed to obtain information of electric characteristics,impact pressure,and plasma temperature.The results of the electric characteristics and the impact pressure were inconsistent with ignition results.The only thing that the ignition success tests had in common was that their plasma all had a relatively long period of high-temperature duration(HTD).It eventually concludes that the ignition mechanism in this research is the microconvection heat transfer rather than the shock initiation,which differs from that of exploding foil initiators detonating explosives.Furthermore,the methods for evaluating the ignition success of semiconductor bridge initiators are not entirely applicable to the tests mentioned in this paper.The HTD is the critical parameter for judging the ignition success,and it is influenced by two factors:the late time discharge and the energy of the electric explosion.The longer time of the late time discharge and the more energy of the electric explosion,the easier it is to expand the HTD,which improves the probability of the ignition success.
基金the Fundamental Research Funds for the Central Universities(Grant No.30920041102)National Natural Science Foundation of China(Grant No.11802134).
文摘The arc ignition system based on charring polymers has advantages of simple structure,low ignition power consumption and multiple ignitions,which bringing it broadly application prospect in hybrid propulsion system of micro/nano satellite.However,charring polymers alone need a relatively high input voltage to achieve pyrolysis and ignition,which increases the burden and cost of the power system of micro/nano satellite in practical application.Adding conductive substance into charring polymers can effectively decrease the conducting voltage which can realize low voltage and low power consumption repeated ignition of arc ignition system.In this paper,a charring conductive polymer ignition grain with a cavity geometry in precombustion chamber,which is composed of PLA and multiwall carbon nanotubes(MWCNT)was proposed.The detailed ignition processes were analyzed and two different ignition mechanisms in the cavity of charring conductive polymers were revealed.The ignition characteristics of charring conductive polymers were also investigated at different input voltages,ignition grain structures,ignition locations and injection schemes in a visual ignition combustor.The results demonstrated that the ignition delay and external energy required for ignition were inversely correlated with the voltages applied to ignition grain.Moreover,the incremental depth of cavity shortened the ignition delay and external energy required for ignition while accelerated the propagation of flame.As the depth of cavity increased from 2 to 6 mm(at 50 V),the time of flame propagating out of ignition grain changed from 235.6 to 108 ms,and values of mean ignition delay time and mean external energy required for ignition decreased from 462.8 to 320 ms and 16.2 to 10.75 J,respectively.The rear side of the cavity was the ideal ignition position which had a shorter ignition delay and a faster flame propagation speed in comparison to other ignition positions.Compared to direct injection scheme,swirling injection provided a more favorable flow field environment in the cavity,which was beneficial to ignition and initial flame propagation,but the ignition position needed to be away from the outlet of swirling injector.At last,the repeated ignition characteristic of charring conductive polymers was also investigated.The ignition delay time and external energy required for ignition decreased with repeated ignition times but the variation was decreasing gradually.
文摘Incorporating aluminum metal-organic frameworks(Al-MOFs)as energetic additives for solid fuels presents a promising avenue for enhancing combustion performance.This study explores the potential benefits of Al-MOF(MIL-53(Al))energetic additive on the combustion performance of hydroxyl-terminated polybutadiene(HTPB)fuel.The HTPB-MOF fuel samples were manufactured using the vacuum-casting technique,followed by a comprehensive evaluation of their ignition and combustion properties using an opposed flow burner(OFB)setup utilizing gaseous oxygen as an oxidizer.To gauge the effectiveness of Al-MOFs as fuel additives,their impact is compared with that of nano-aluminum(nAl),another traditional additive in HTPB fuel.The results indicate that the addition of 15%(mass fraction)nAl into HTPB resulted in the shortest ignition delay time(136 ms),demonstrating improved ignition performance compared to pure HTPB(273 ms).The incorporation of Al-MOF in HTPB also reduced ignition delay times to 227 ms and 189 ms,respectively.Moreover,under high oxidizer mass flux conditions(79—81 kg/(m^(2)s)),HTPB fuel with 15%nAl exhibited a substantial 83.2%increase in regression rate compared to the baseline HTPB fuel,highlighting the positive influence of nAl on combustion behavior.In contrast,HTPB-MOF with a 15%Al-MOF additive showed a 32.7%increase in regression rate compared to pure HTPB.These results suggest that HTPB-nAl outperforms HTPB-MOF in terms of regression rates,indicating a more vigorous and rapid burning behavior.
基金supported by the Key Projects of Schoolenterprise Joint Fund(No.U22B20120)the National Science Fund for Distinguished Young Scholars(No.52107141)。
文摘Booming low-power electric propulsion systems require 1–2 A hollow cathodes.Such cathodes are expected to go through more frequent ignitions in the low orbit,but the impact of cyclic ignitions on such 1–2 A barium tungsten hollow cathodes with a heater was not clear.In this study,a 12,638-cyclic ignition test and a 6,000-hour-long life test on two identical cathodes were carried out.The discharge voltage of the cathode and the erosion of the orifice after cyclic ignition were all larger than that of the cathode after stable operation.This indicated that the impact of cycle ignition on the discharge performance of a low current BaO-W cathode with a heater was higher than that of stable operation.The results of the ion energy distribution function measured during the ignition period indicated that the main reason for the orifice expansion was ion bombardment.Therefore,it was necessary to pay attention to the number of ignitions for the lifetime of this kind of cathode.
基金the Presidential Foundation of CAEP(Grant No.YZJJZQ2023008)the National Natural Science Foundation of China(Grant No.NSFC 12372342)for financial support of this work.
文摘Understanding the response of solid combustibles under high radiant fluxes is critical in predicting the thermal damage from extreme scenarios.Unlike the more moderate radiant fluxes in conventional hydrocarbon fires,extreme events such as strong explosion,concentrated sunlight and directed energy can generate dynamic radiant fluxes at the MW/m^(2) level,creating a unique threat to materials.This study investigates the pyrolysis and spontaneous ignition behaviors of corrugated cardboard by using both experimental and numerical methods,under 10-cm dynamic high radiant fluxes ranging from 0.2 to 1.25 MW/m^(2) for 10 s.The spontaneous ignition process at dynamic high radiant fluxes was recorded and quantified.Two ignition modes were found at the critical radiant flux of 0.4 MW/m^(2),namely hot-gas spontaneous ignition and hot-residue piloted ignition.The latter is not the focus of this paper due to its extremely small probability of occurrence.The research reveals that the increase in flux intensity induces shorter delay times for both pyrolysis and ignition,lower ignition energy density,along with a corresponding rise in the critical mass flux and surface temperature at ignition moment.The simulation results are generally aligned with the experimental findings,despite some divergences may be attributed to model simplifications and parameter assumptions.The work contributes to a deeper insight into material behavior under extreme radiation,with valuable implications for fire safety and hazard assessment.
基金support from the National Natural Science Foundation of China(Grant No.22175160)the Science Challenge Project(Grant No.TZ2018004)。
文摘5-amino-4-nitrobenzo[1,2-c:3,4-c']bis([1,2,5]oxadiazole)1,6-dioxide(CL-18)exhibits significant potential as an initiating explosive.However,its current synthesis process remains non-scalable due to low yields and safety risks.In this study,we have developed a simple and safe synthetic route for CL-18.It was synthesized from 3,5-dihaloanisole in a four-step reaction with an overall yield exceeding 60%,surpassing all reported yields in the literature.Subsequently,recrystallization of CL-18 was successfully achieved by carefully selecting appropriate solvents and antisolvents to reduce its mechanical sensitivity.Ultimately,when DMF-ethanol was employed as the recrystallization solvent system,satisfactory product yield(>90%)and reduced mechanical sensitivity(IS=15 J;FS=216 N)were obtained.Additionally,CL-18 is derived from the rearrangement of oxygen atoms on i-CL-18 furoxan,and a comparative analysis of their physicochemical properties was conducted.The thermal stability of both compounds is similar,with onset decomposition temperatures recorded at 186 and 182℃respectively.Similarly,they exhibit 5 s breaking point temperatures of 236 and 237℃.Additionally,we present novel insights into the positional-isomerization-laser-ignition performance of CL-18 and its isomer i-CL-18 using laser irradiation for the first time.Remarkably,our findings demonstrate that i-CL-18 exhibits enhanced laser sensitivity,as it can be directly ignited by a 1064 nm wavelength laser,whereas CL-18 lacks this characteristic.
基金supported by the National Natural Science Foundation of China(Grant Nos.22275092,52102107 and 52372084)the Fundamental Research Funds for the Central Universities(Grant No.30923010920)。
文摘Energetic Semiconductor bridge(ESCB)based on reactive multilayered films(RMFs)has a promising application in the miniature and intelligence of initiator and pyrotechnics device.Understanding the ignition enhancement mechanism of RMFs on semiconductor bridge(SCB)during the ignition process is crucial for the engineering and practical application of advanced initiator and pyrotechnics devices.In this study,a one-dimensional(1D)gas-solid two-phase flow ignition model was established to study the ignition process of ESCB to charge particles based on the reactivity of Al/MoO_(3) RMFs.In order to fully consider the coupled exothermic between the RMFs and the SCB plasma during the ignition process,the heat release of chemical reaction in RMFs was used as an internal heat source in this model.It is found that the exothermal reaction in RMFs improved the ignition performance of SCB.In the process of plasma rapid condensation with heat release,the product of RMFs enhanced the heat transfer process between the gas phase and the solid charge particle,which accelerated the expansion of hot plasma,and heated the solid charge particle as well as gas phase region with low temperature.In addition,it made up for pressure loss in the gas phase.During the plasma dissipation process,the exothermal chemical reaction in RMFs acted as the main heating source to heat the charge particle,making the surface temperature of the charge particle,gas pressure,and gas temperature rise continuously.This result may yield significant advantages in providing a universal ignition model for miniaturized ignition devices.
基金Project supported by the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDA 25051000)。
文摘In order to address the issue of gold mixing caused by the Kelvin-Helmholtz instability(KHI)in the double-cone ignition(DCI)scheme,we investigate the growth rate of the KHI at the bi-interface of the DCI scheme after applying a coating.This is done by solving the hydrodynamic equations for an ideal incompressible fluid using linear theory.Ultimately,it is discovered that applying a coating with a thickness slightly above h=0.5(λ+10μm)and a density somewhat lower than that of the target layer can effectively reduce the growth rate of interfacial KHI.This work provides theoretical references for studying the bi-interface KHI in the DCI scheme.
基金Project supported by the Strategic Priority Research Program of Chinese Academy of Sciences (Grant Nos. XDA25051000 and XDA 25010100)。
文摘In the double-cone ignition schemes(DCIS), the deuterium–tritium target shell is ablated and compressed by a highpower nanosecond laser in Au-cones to generate plasmas. Under the actions of spherically symmetric compression and acceleration along the Au cone, they will be ejected out of the cone mouth and collide with each other. The plasmas experience conversion from kinetic energy to internal energy at the vertex of the geometric center of two Au cones that are symmetric to each other, because of which high-density fusion plasmas are preheated. This key physical process has undergone experimental verification on the Shenguang-II upgraded facility in China. Apparently, the improvement and optimization of the velocity of plasmas in hypersonic jet flow at the cone mouth are crucial for the success of the DCIS. In the DCIR7 experiment of the Shenguang-II upgraded facility, a velocity yield of approximately 130–260 km/s was achieved for the plasmas at the cone mouth, with a result of nearly 300 km/s based on numerical simulation. In this paper, theoretical analysis is performed as regards the process, in which target shells are ablated and compressed by laser to generate highvelocity plasmas ejected through jet flow. Based on this analysis, the formula for the velocity of plasmas in supersonic jet flow at the cone mouth is proposed. This study also provides measures that are more effective for improving the kinetic energy of plasmas and optimizing energy conversion efficiency, which can serve as theoretical references for the adjustment and optimization of processes in subsequent experiments.
基金Project supported by the staff of the Shenguang-Ⅱ upgrade Laser facilityThis study was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDA25010100,XDA25010300,XDA25030100,XDA25030200,and XDA25051000)+2 种基金the National Natural Science Foundation of China(Grant Nos.11827807 and 12105359)the Open Foundation of Key Laboratory of High Power Laser and Physics of Chinese Academy of Sciences(Grant No.SGKF202105)the Chinese Academy of Sciences Youth Interdisciplinary Team(Grant No.JCTD-2022-05).
文摘We developed a monochromatic crystal backlight imaging system for the double-cone ignition(DCI) scheme, employing a spherically bent quartz crystal. This system was used to measure the spatial distribution and temporal evolution of the head-on colliding plasma from the two compressing cones in the DCI experiments. The influence of laser parameters on the x-ray backlighter intensity and spatial resolution of the imaging system was investigated. The imaging system had a spatial resolution of 10 μm when employing a CCD detector. Experiments demonstrated that the system can obtain time-resolved radiographic images with high quality, enabling the precise measurement of the shape, size, and density distribution of the plasma.
基金National Natural Science Foundation of China(U22B20131)State Key Laboratory of Explosion Science and Technology(QNKT23-10)for supporting this project.
文摘Investigating the ignition response of nitrate ester plasticized polyether(NEPE) propellant under dynamic extrusion loading is of great significant at least for two cases. Firstly, it helps to understand the mechanism and conditions of unwanted ignition inside charged propellant under accident stimulus.Secondly, evaluates the risk of a shell crevice in a solid rocket motor(SRM) under a falling or overturning scene. In the present study, an innovative visual crevice extrusion experiment is designed using a dropweight apparatus. The dynamic responses of NEPE propellant during extrusion loading, including compaction and compression, rapid shear flow into the crevice, stress concentration, and ignition reaction, have been firstly observed using a high-performance high-speed camera. The ignition reaction is observed in the triangular region of the NEPE propellant sample above the crevice when the drop weight velocity was 1.90 m/s. Based on the user material subroutine interface UMAT provided by finite element software LS-DYNA, a viscoelastic-plastic model and dual ignition criterion related to plastic shear dissipation are developed and applied to the local ignition response analysis under crevice extrusion conditions. The stress concentration occurs in the crevice location of the propellant sample, the shear stress is relatively large, the effective plastic work is relatively large, and the ignition reaction is easy to occur. When the sample thickness decreases from 5 mm to 2.5 mm, the shear stress increases from 22.3 MPa to 28.6 MPa, the critical value of effective plastic work required for ignition is shortened from 1280 μs to 730 μs, and the triangular area is easily triggering an ignition reaction. The propellant sample with a small thickness is more likely to stress concentration, resulting in large shear stress and effective work, triggering an ignition reaction.
基金the Science and Technology on Applied Physical Chemistry Laboratory, China (Grant No.6142602220101) to provide fund for conducting experiments。
文摘Explosion-electricity coupling(EEC) is a technical method to induce electric energy into the plasma material produced by explosion to improve the output of explosion.Exploding foil initiator(EFI) which could produce plasma during electric explosion can serve as a good carrier for studying the EEC.To investigate the enhancement ability and mechanism of EEC in EFI ignition performance,a kind of EFI chips which could realize the EEC effect was designed and fabricated to observe the characteristics of current and voltage,flyer and plasma temperature during Boron Potassium Nitrate(BPN) ignition of the EFI.It was found that the EEC could enhance EFI ignition in terms of energy utilization,ignition contact surface,and high-temperature sustainability of plasma:firstly,the EEC prolonged the late time discharge(LTD) phase of the electric explosion,making the energy of capacitor effectively utilized;secondly,the EEC could create a larger area of ignition contact surface;last of all,the EEC effect enhanced its hightemperature sustainability by sustaining continuous energy input to plasma.It also was found that the ignition voltage of BPN could be reduced by nearly 600 V under the condition of 0.4 μF capacitance.The research has successfully combined EEC with EFI,revealing the behavioral characteristics of EEC and demonstrating its effective enhancement of EFI ignition.It introduces a new approach to improving EFI output,which is conducive to low-energy ignition of EFI,and expected to take the ignition technology of EFI to a new level.
基金Project supported by the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDA_(2)5051000)the National Key R&D Program of China(Grant No.2023YFA1608400)+1 种基金the National Natural Science Foundation of China(Grant No.12005008)the Natural Science Foundation of Top Talent of SZTU(Grant No.GDRC202209).
文摘A model for fast electron-driven high-density plasma is proposed to describe the effect of injected fast electrons on the temperature and inner pressure of the plasma in the fast heating process of the double-cone ignition(DCI)scheme.Due to the collision of the two low-density plasmas,the density and volume of the high-density plasma vary.Therefore,the ignition temperature and energy requirement of the high-density plasma vary at different moments,and the required energy for hot electrons to heat the plasma also changes.In practical experiments,the energy input of hot electrons needs to be considered.To reduce the energy input of hot electrons,the optimal moment and the shortest time for injecting hot electrons with minimum energy are analyzed.In this paper,it is proposed to inject hot electrons for a short time to heat the high-density plasma to a relatively high temperature.Then,the alpha particles with the high heating rate and PdV work heat the plasma to the ignition temperature,further reducing the energy required to inject hot electrons.The study of the injection time of fast electrons can reduce the energy requirement of fast electrons for the high-density plasma and increase the probability of successful ignition of the high-density plasma.
文摘Aim To present a new kind of rapid ignition tube for igniting the propellant of heavy calibre gun uniformly and synchronistically so as to decrease the pressure wave. Methods Firing tests were carried out. Relationships between pressure and time ( p t curves) at different positions of the tube are measured. The mode of igniter tube of quasi one dimensional two phase flow is given. Results\ The test results indicate that the speed of ignition front in the ignition tube is very fast and the pressure distribution within the igniter tube is uniform. Results of experiments and numerical calculations of the combustion in the igniter tube are in reasonable agreement. Conclusion\ The new igniter tubes have a very high velocity of propagation of ignition stimuli and can ignite the propellant bed synchronistically.
文摘An engine cyclic variation model has been built by using the residual gas temperature for the n th cycle as the input of the model, through constant pressure intake process, adiabatic compression process, constant volume combustion process, adiabatic expansion process, adiabatic blow down process and constant pressure exhaust process to approximate the thermodynamic processes in the cylinder, finally the residual gas temperature for the ( n+1) th cycle can be estimated. Because of the adding of engine operating parameters such as engine speed, spark advance, equivalence ratio, intake air pressure, intake air temperature to the model, effects of these parameters on cyclic variation can be estimated quantitatively. Since residual gas temperature fluctuation between cycles reflects the circumstances of engine cyclic variation, parameters to which residual gas temperature is sensitive are most likely used as the means to control cyclic variation. Model simulation shows that for the nearly stiochiometric mixture, cyclic variation is not obvious or even quite stable, but for the lean mixture, under the circumstances of partial load and larger spark advances, engine cyclic variations occur chaotically or with bifurcation.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51776223 and 91741112)
文摘At present, aero-engines face a major need to widen the ignition envelope. In order to provide a technical support to expand the high altitude ignition envelope of aero-engines, in this article we propose a novel ignition technology, i.e., "precombustion plasma jet ignition technology". In this paper, we also design a pre-combustion plasma jet igniter. Its discharge characteristics, jet characteristics, and ignition effects are studied. The results show that increasing the equivalent ratio of jet gas can enhance the discharge stability and increase the duty cycle. At the same time, it can reduce working power and energy consumption. The increase of equivalent ratio in jet gas can enhance the length and ignition area of plasma jet.In the process of ignition, the pre-combustion plasma jet igniter has obvious advantages, suchn as shortening the ignition delay time and enlarging the ignition boundary. When the airflow velocity is 39.11 m/s and the inlet air temperature is80℃, compared with the spark igniter and the air plasma jet igniter, the pre-combustion plasma jet igniter has an ignition boundary that is expanded by 319.8% and 55.7% respectively.
基金funded under the National Innovation and Exploration Research Programsupported by the State Key Laboratory of Explosion Science and Technology Foundation of China
文摘Reactive material projectiles can be an extremely efficient lethality enhancement technology that incorporates the defeat mechanisms of chemical energy and kinetic energy.This paper presents such a research on the enhanced ignition behavior of reactive material projectiles impacting a fuel-filled tank.Firstly,the ignition process description of the fuel-filled tank impacted by inert metal and reactive material projectiles is presented.Secondly,ballistic impact experiments are performed to investigate the ignition effects of the fuel-filled tank impacted by reactive material versus tungsten alloy projectiles with mass matched.The fuel tank used for the experiments is a cylindrical steel casing structure filled with aviation kerosene and sealed with aluminum cover plates on both ends using screw bolts.The experimental results indicate that,compared with impacts from tungsten alloy projectiles,there is dramatically enhanced structural damage to the fuel-filled tank and an enhanced ignition effect caused by reactive material projectile impacts.Finally,an analytical model is developed,by which the effects of the aluminum cover plate thickness on critical structural failure energy of the fuel-filled tank and the total energy of the reactive material projectile deposited into the fuel-filled tank are discussed.The analysis shows a good agreement with the experiments.
基金provided by the National Institute for Occupational Safety and Health,NIOSH(No.211-2014-60050)
文摘Most, if not all longwall gob areas accumulate explosive methane-air mixtures that pose a deadly hazard to miners. Numerous mine explosions have originated from explosive gas zones(EGZs) in the longwall gob. Since 2010, researchers at the Colorado School of Mines(CSM) have studied EGZ formation in longwall gobs under two long-term research projects funded by the National Institute for Occupational Safety and Health. Researchers used computational fluid dynamics along with in-mine measurements. For the first time, they demonstrated that EGZs form along the fringe areas between the methane-rich atmospheres and the fresh air ventilated areas along the working face and present an explosion and fire hazard to mine workers. In this study, researchers found that, for progressively sealed gobs, a targeted injection of nitrogen from the headgate and tailgate, along with a back return ventilation arrangement, will create a dynamic seal of nitrogen that effectively separates the methane zone from the face air and eliminates the EGZs to prevent explosions. Using this form of nitrogen injection to create dynamic seals should be a consideration for all longwall operators.
基金the support of National Natural Science Foundation of China (No. 51405315)the Talents Introduction Project of Sichuan University (No. yj2012043)
文摘Direct current plasma torches have been applied to generate unique sources of thermal energy in many industrial applications. Nevertheless, the successful ignition of a plasma torch is the key process to generate the unique source （plasma jet）. However, there has been tittle study on the underlying mechanism of this key process. A thorough understanding of the ignition process of a plasma torch will be helpful for optimizing the design of the plasma torch structure and selection of the ignition parameters to prolong the service life of the ignition module. Thus, in this paper, the ignition process of a segmented plasma torch （SPT） is theoretically and experimentally modeled and analyzed. Corresponding electrical models of different stages of the ignition process axe set up and used to derive the electrical parameters, e.g. the variations of the arc voltage and arc current between the cathode and anode. In addition, the experiments with different ignition parameters on a home-made SPT have been conducted. At the same time, the variations of the arc voltage and arc current have been measured, and used to verify the ones derived in theory and to determine the optimal ignition parameters for a particular SPT.
