| Facing the great demand of fossil energy and the increasingly bad natural environment,hydrogen energy has attracted much attention as a clean alternative energy.Hydrogen,as a fuel for combustion power equipment,is an ideal way to utilize hydrogen energy.In the turbulent atmosphere,rich hydrogen-air premixed gas flame propagation speed is faster,and the amount of oxygen deficiency due to the formation of NOx is relatively low,these advantages are in line with the requirements of automotive engines for high power,high efficiency and low emissions.Therefore,the research on turbulent premixed combustion characteristics of rich hydrogen-air has great significance to guiding the design of hydrogen fuel engine.The basic research work on the combustion characteristics of turbulent premixed flame has been carried out for a long time,but because of the complexity of combustion in turbulent environment,the research is mostly on phenomenological interpretation and simple measurement of flame images.Therefore,the theoretical analysis of the turbulent premixed combustion characteristics is absent.Based on the background of the times and focused on the turbulent premixed flame,the basic research work on turbulence premixed combustion characteristics of rich hydrogen-air at different pressures,turbulence intensities and equivalence ratios is carried out in this paper.The main contents of this paper are as follows:First of all,the constant volume combustion experiment system has been improved.Pixel gain is used to improve the quality of flame images.Besides,the graph processing software is developed to extract the basic information and calculate the related parameters of the flame images.Secondly,the influence factors of turbulent premixed flame structure characteristics are studied,and the interaction between turbulence and flame structure is analyzed in detail.The structure characteristics of hydrogen-air turbulence premixed flame were investigated under the different pressure,turbulence intensity and equivalence ratio.The fold factor and stretch rate are analyzed quantitatively.At the same time,the related research on turbulent premixed flame propagation characteristics is carried out,and the influencing factors and variation rules of turbulent premixed flame propagation characteristics are analyzed.For different initial conditions,carried out a detailed analysis of the variation laws and the influence factors of rich hydrogen-air turbulent premixed combustion flame propagation speed and the unstretched flame propagation speed with flame radius.The influence mechanism of turbulent flow on flame propagation characteristics is explained.Finally,the explosion characteristics of rich hydrogen-air are studied.The explosion parameters such as explosion pressure,maximum explosion pressure,pressure rise rate and rapid combustion period are studied in detail under different turbulence intensity and equivalence ratio. |
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