The intake swirl in the cylinder was induced by a swirler which was fixed in one of two intake ports. In order to understand the characteristics of the intake swirl, a transparent water analog was designed which simul...The intake swirl in the cylinder was induced by a swirler which was fixed in one of two intake ports. In order to understand the characteristics of the intake swirl, a transparent water analog was designed which simulated 150 type single cylinder engine. At the same time, the particle image velocimetry was used to measure the flow fields induced by various swirlers in the analog. After measurement, a new method was presented to evaluate the intensity of the intake swirl. Then, when the measured sections, the lifts of valve and the swirlers were different, the calculated results of the flow field were compared.展开更多
Aim To investigate the spray particle velocity and its distribution characteristics. Methods\ A set of PIV (particle image velocimetry) system was developed and used to observe and analyze the spray particle velocity...Aim To investigate the spray particle velocity and its distribution characteristics. Methods\ A set of PIV (particle image velocimetry) system was developed and used to observe and analyze the spray particle velocity field. Results and Conclusion\ Double exposure image of the spray particle within the region of 10-50 mm from the nozzle tip was recorded and analyzed by the IBAS2000 analysis system. Some characteristics of the spray particle velocity and its distribution were obtained.展开更多
In order to reveal the temperature change in coal gas desorption process,the temperature variation in coal gas desorption process under different particle sizes is analyzed with infrared thermal imager.The infrared vi...In order to reveal the temperature change in coal gas desorption process,the temperature variation in coal gas desorption process under different particle sizes is analyzed with infrared thermal imager.The infrared video signals obtained by the experiment are processed with SAT.Then the infrared radiation signals are processed by EMD with Hilbert–Huang and the infrared radiation noise is effectively removed.The research results show that the desorption process,with the change of the temperature,is an endothermic process.The coal absorbs heat when the gas is desorbed and the temperature drops.The coal body temperature drop range is obviously related to coal particle size.The smaller the particle size is,the bigger the temperature drop becomes.The temperature variation curves in the process of coal gas desorption under different particle sizes are fitted,and they comply with the exponential function.The research results lay the theoretical and experimental foundation for non-contact prediction on working face of coal and gas outburst with infrared thermal image technology.展开更多
The flow field of pulsing air separation is normally in an unsteady turbulence state.With the application of the basic principles of multiphase turbulent flows,we established the dynamical computational model,which sh...The flow field of pulsing air separation is normally in an unsteady turbulence state.With the application of the basic principles of multiphase turbulent flows,we established the dynamical computational model,which shows a remarkable variation of the unstable pulsing air flow field.CFD(computational fluid dynamics) was used to conduct the numerical simulation of the actual geometric model of the classifier.The inside velocity of the flowing fields was analyzed later.The simulation results indicate that the designed structure of the active pulsing air classifier provided a favorable environment for the separation of the particles with different physical characters by density.We shot the movement behaviors of the typical tracer grains in the active pulsing flow field using a high speed dynamic camera.The displacement and velocity curves of the particles in the continuous impulse periods were then analyzed.The experimental results indicate that the effective separation by density of the particles with the same settling velocity and different ranges of the density and particle size can be achieved in the active pulsing airflow field.The experimental results provide an agreement with the simulation results.展开更多
文摘The intake swirl in the cylinder was induced by a swirler which was fixed in one of two intake ports. In order to understand the characteristics of the intake swirl, a transparent water analog was designed which simulated 150 type single cylinder engine. At the same time, the particle image velocimetry was used to measure the flow fields induced by various swirlers in the analog. After measurement, a new method was presented to evaluate the intensity of the intake swirl. Then, when the measured sections, the lifts of valve and the swirlers were different, the calculated results of the flow field were compared.
文摘Aim To investigate the spray particle velocity and its distribution characteristics. Methods\ A set of PIV (particle image velocimetry) system was developed and used to observe and analyze the spray particle velocity field. Results and Conclusion\ Double exposure image of the spray particle within the region of 10-50 mm from the nozzle tip was recorded and analyzed by the IBAS2000 analysis system. Some characteristics of the spray particle velocity and its distribution were obtained.
基金provided by the National Natural Science Foundation of China (No.51174157)the Doctor Start-up Fund of Xi’an University of Science and Technology of China (No.2013QDJ005)the Research Development Fund of Xi’an University of Science and Technology of China (No.201244)
文摘In order to reveal the temperature change in coal gas desorption process,the temperature variation in coal gas desorption process under different particle sizes is analyzed with infrared thermal imager.The infrared video signals obtained by the experiment are processed with SAT.Then the infrared radiation signals are processed by EMD with Hilbert–Huang and the infrared radiation noise is effectively removed.The research results show that the desorption process,with the change of the temperature,is an endothermic process.The coal absorbs heat when the gas is desorbed and the temperature drops.The coal body temperature drop range is obviously related to coal particle size.The smaller the particle size is,the bigger the temperature drop becomes.The temperature variation curves in the process of coal gas desorption under different particle sizes are fitted,and they comply with the exponential function.The research results lay the theoretical and experimental foundation for non-contact prediction on working face of coal and gas outburst with infrared thermal image technology.
基金the financial support provided by the National Natural Science Foundation of China (No.51074156)the Natural Science Foundation of China for InnovativeResearch Group (No. 50921002)+1 种基金the Natural Science Foundation of Jiangsu Province of China (No. BK2010002)the Fundamental Research Funds for the Central Universities (No. 2010ZDP01A06)
文摘The flow field of pulsing air separation is normally in an unsteady turbulence state.With the application of the basic principles of multiphase turbulent flows,we established the dynamical computational model,which shows a remarkable variation of the unstable pulsing air flow field.CFD(computational fluid dynamics) was used to conduct the numerical simulation of the actual geometric model of the classifier.The inside velocity of the flowing fields was analyzed later.The simulation results indicate that the designed structure of the active pulsing air classifier provided a favorable environment for the separation of the particles with different physical characters by density.We shot the movement behaviors of the typical tracer grains in the active pulsing flow field using a high speed dynamic camera.The displacement and velocity curves of the particles in the continuous impulse periods were then analyzed.The experimental results indicate that the effective separation by density of the particles with the same settling velocity and different ranges of the density and particle size can be achieved in the active pulsing airflow field.The experimental results provide an agreement with the simulation results.
