Due to the pressure gain combustion characteristics,the rotating detonation combustor(RDC)can enhance thermodynamic cycle efficiency.Therefore,the performance of gas-turbine engine can be further improved with this co...Due to the pressure gain combustion characteristics,the rotating detonation combustor(RDC)can enhance thermodynamic cycle efficiency.Therefore,the performance of gas-turbine engine can be further improved with this combustion technology.In the present study,the RDC operation performance with a turbine guide vane(TGV)is experimentally investigated.Hydrogen and air are used as propellants while hydrogen and air mass flow rate are about 16.1 g/s and 500 g/s and the equivalence ratio is about 1.0.A pre-detonator is used to ignite the mixture.High-frequency dynamic pressure transducers and silicon pressure sensors are employed to measure pressure oscillations and static pressure in the combustion chamber.The experimental results show that the steady propagation of rotating detonation wave(RDW)is observed in the combustion chamber and the mean propagation velocity is above 1650 m/s,reaching over 84%of theoretical Chapman-Jouguet detonation velocity.Clockwise and counterclockwise propagation directions of RDW are obtained.For clockwise propagation direction,the static pressure is about 15%higher in the combustor compared with counterclockwise propagation direction,but the RDW dominant frequency is lower.When the oblique shock wave propagates across the TGV,the pressure oscillations reduces significantly.In addition,as the detonation products flow through the TGV,the static pressure drops up to 32%and 43%for clockwise and counterclockwise propagation process respectively.展开更多
numerical simulation was conducted to study the influence of bleeding. The Euler-Lagrange method was used to investigate the two-phase turbulent combustion flow. Standard k-ε turbulent model was adopted in the contin...numerical simulation was conducted to study the influence of bleeding. The Euler-Lagrange method was used to investigate the two-phase turbulent combustion flow. Standard k-ε turbulent model was adopted in the continuous phase simulation and particle-trajectory model was adopted in the dispersed phase simulation. The results demonstrates: air bleeding can improve the flow field after the strut and the stability of trapped vortex in the cavity; change of bleeding temperature has little effect on the total pressure recovery coefficient and significant effect on combustion efficiency; When fuel-air ratio changes, the combustor performs better in a lean oil state.展开更多
In order to reveal combustion characteristics of H_2/air mixture in a micro-combustor with and without bluff body, the effects of inlet velocities, equivalence ratios and bluff body's blockage ratios on the temper...In order to reveal combustion characteristics of H_2/air mixture in a micro-combustor with and without bluff body, the effects of inlet velocities, equivalence ratios and bluff body's blockage ratios on the temperature field, pressure of the combustor wall, combustion efficiency and blow-off limit were investigated. The numerical results indicate that the sudden expansion plate micro combustor with bluff body could enhance the turbulent disturbance of the mixed gas in the combustion chamber and the combustion condition is improved. Moreover, a low-speed and high temperature recirculation region was formed between the sudden expansion step and the bluff body so that the high and uniform wall temperature(>1000 K) could be gotten. As a result, it could strengthen the mixing process, prolong the residence time of gas, control the flame position effectively and widen the operation range by the synergistic effect of the bluff body and steps. When the blockage ratio ranged from 0.3 to 0.6, it could be found that the bluff body could play a stabilizing effect and expand combustion blow burning limit, and combustion efficiency firstly was increased with the inlet velocity and equivalence ratio, and then was decreased.展开更多
This paper presents a robust model reference adaptive control scheme to deal with un-certain time delay in the dynamical model of a ?uidized bed combustor for sewage sludge. Thetheoretical analysis and simulation resu...This paper presents a robust model reference adaptive control scheme to deal with un-certain time delay in the dynamical model of a ?uidized bed combustor for sewage sludge. Thetheoretical analysis and simulation results show that the proposed scheme can guarantee not onlystability and robustness, but also the adaptive decoupling performance of the system.展开更多
The paper sheds light on the idle lean blow off(LBO)problem for high fuel air ratio(FAR)com⁃bustor,which is impossible to be addressed with traditional aero combustor design.A significant improvement in aero combustor...The paper sheds light on the idle lean blow off(LBO)problem for high fuel air ratio(FAR)com⁃bustor,which is impossible to be addressed with traditional aero combustor design.A significant improvement in aero combustor design is required to resolve the idle LBO issue.The authors detailed a practical and efficient solu⁃tion,which not only solved the idle LBO issue but also defined the aero-thermal design for high-FAR combustor.The design will usher in a new era of aero combustor.展开更多
This paper discusses two industrial control applications using advanced control techniques. They are theoptimal-tuning nonlinear PID control of hydraulic systems and the neural predictive control of combustor acoustic...This paper discusses two industrial control applications using advanced control techniques. They are theoptimal-tuning nonlinear PID control of hydraulic systems and the neural predictive control of combustor acoustic ofgas turbines. For hydraulic control systems, an optimal PID controller with inverse of dead zone is introduced toovercome the dead zone and is designed to satisfy desired time-domain performance requirements. Using the adaptivemodel, an optimal-tuning PID control scheme is proposed to provide optimal PID parameters even in the case wherethe system dynamics is time variant. For combustor acoustic control of gas turbines, a neural predictive controlstrategy is presented, which consists of three parts: an output model, output predictor and feedback controller. Theoutput model of the combustor acoustic is established using neural networks to predict the output and overcome thetime delay of the system, which is often very large, compared with the sampling period. The output-feedback con-troller is introduced which uses the output of the predictor to suppress instability in the combustion process. The a-bove control strategies are implemented in the SIMULINK/dSPACE controller development environment. Theirperformance is evaluated on the industrial hydraulic test rig and the industrial combustor test rig.展开更多
基金the National Natural Science Foundation of China(No.11702143 and 11802137)the Fundamental Research Funds for the Central Universities(No.30918011343 and 30919011259).
文摘Due to the pressure gain combustion characteristics,the rotating detonation combustor(RDC)can enhance thermodynamic cycle efficiency.Therefore,the performance of gas-turbine engine can be further improved with this combustion technology.In the present study,the RDC operation performance with a turbine guide vane(TGV)is experimentally investigated.Hydrogen and air are used as propellants while hydrogen and air mass flow rate are about 16.1 g/s and 500 g/s and the equivalence ratio is about 1.0.A pre-detonator is used to ignite the mixture.High-frequency dynamic pressure transducers and silicon pressure sensors are employed to measure pressure oscillations and static pressure in the combustion chamber.The experimental results show that the steady propagation of rotating detonation wave(RDW)is observed in the combustion chamber and the mean propagation velocity is above 1650 m/s,reaching over 84%of theoretical Chapman-Jouguet detonation velocity.Clockwise and counterclockwise propagation directions of RDW are obtained.For clockwise propagation direction,the static pressure is about 15%higher in the combustor compared with counterclockwise propagation direction,but the RDW dominant frequency is lower.When the oblique shock wave propagates across the TGV,the pressure oscillations reduces significantly.In addition,as the detonation products flow through the TGV,the static pressure drops up to 32%and 43%for clockwise and counterclockwise propagation process respectively.
文摘numerical simulation was conducted to study the influence of bleeding. The Euler-Lagrange method was used to investigate the two-phase turbulent combustion flow. Standard k-ε turbulent model was adopted in the continuous phase simulation and particle-trajectory model was adopted in the dispersed phase simulation. The results demonstrates: air bleeding can improve the flow field after the strut and the stability of trapped vortex in the cavity; change of bleeding temperature has little effect on the total pressure recovery coefficient and significant effect on combustion efficiency; When fuel-air ratio changes, the combustor performs better in a lean oil state.
基金Project(51176045)supported by the National Natural Science Foundation of ChinaProject(201208430262)supported by the National Studying Abroad Foundation of China
文摘In order to reveal combustion characteristics of H_2/air mixture in a micro-combustor with and without bluff body, the effects of inlet velocities, equivalence ratios and bluff body's blockage ratios on the temperature field, pressure of the combustor wall, combustion efficiency and blow-off limit were investigated. The numerical results indicate that the sudden expansion plate micro combustor with bluff body could enhance the turbulent disturbance of the mixed gas in the combustion chamber and the combustion condition is improved. Moreover, a low-speed and high temperature recirculation region was formed between the sudden expansion step and the bluff body so that the high and uniform wall temperature(>1000 K) could be gotten. As a result, it could strengthen the mixing process, prolong the residence time of gas, control the flame position effectively and widen the operation range by the synergistic effect of the bluff body and steps. When the blockage ratio ranged from 0.3 to 0.6, it could be found that the bluff body could play a stabilizing effect and expand combustion blow burning limit, and combustion efficiency firstly was increased with the inlet velocity and equivalence ratio, and then was decreased.
基金Supported by National Natural Science Foundation of P.R.China(60374001,60334030)the Chinese Ministry of Education(20030006003)
文摘This paper presents a robust model reference adaptive control scheme to deal with un-certain time delay in the dynamical model of a ?uidized bed combustor for sewage sludge. Thetheoretical analysis and simulation results show that the proposed scheme can guarantee not onlystability and robustness, but also the adaptive decoupling performance of the system.
文摘The paper sheds light on the idle lean blow off(LBO)problem for high fuel air ratio(FAR)com⁃bustor,which is impossible to be addressed with traditional aero combustor design.A significant improvement in aero combustor design is required to resolve the idle LBO issue.The authors detailed a practical and efficient solu⁃tion,which not only solved the idle LBO issue but also defined the aero-thermal design for high-FAR combustor.The design will usher in a new era of aero combustor.
文摘This paper discusses two industrial control applications using advanced control techniques. They are theoptimal-tuning nonlinear PID control of hydraulic systems and the neural predictive control of combustor acoustic ofgas turbines. For hydraulic control systems, an optimal PID controller with inverse of dead zone is introduced toovercome the dead zone and is designed to satisfy desired time-domain performance requirements. Using the adaptivemodel, an optimal-tuning PID control scheme is proposed to provide optimal PID parameters even in the case wherethe system dynamics is time variant. For combustor acoustic control of gas turbines, a neural predictive controlstrategy is presented, which consists of three parts: an output model, output predictor and feedback controller. Theoutput model of the combustor acoustic is established using neural networks to predict the output and overcome thetime delay of the system, which is often very large, compared with the sampling period. The output-feedback con-troller is introduced which uses the output of the predictor to suppress instability in the combustion process. The a-bove control strategies are implemented in the SIMULINK/dSPACE controller development environment. Theirperformance is evaluated on the industrial hydraulic test rig and the industrial combustor test rig.
