Effect Of Disturbed Flow Configuration On Induced Turbulence Characteristics Of Hydrogen-Air Pre-mixture

In this paper,we study the combustion characteristics of hydrogen-air premixed in constant volume combustion bomb with a disturbing device.First of all,The flame is induced into turbulence when it goes through the mesh,Flame propagation process is divided into three stages: the initial phase of the flame,the acceleration phase of the flame and the stability phase of the flame.In order to find out the reason of the flame acceleration,we analyze the pressure data and schlieren pictures.As a result,the cause of flame acceleration is the pressure difference between the upper and the lower combustion chamber lead to the ongoing jet,the flame are induced to be turbulent flame,the high velocity of jet let to large penetration,burning area is increased,then the flame propagation velocity is increased.Secondly,this paper selects the blockage ratio as turbulence parameters,By changing the initial pressure,equivalence ratio and initial temperature,the schlieren images and the pressure data of the upper and lower combustion chamber are obtained,which are utilized to select optimal parameter of disturbed device.By analysising the flame propagation speed,combustion duration and the rate of change of combustion duration,we can find out:(1)、When initial condition is constant,there is a best blocking ratio,the combustion duration is shortest.(2)、When the initial temperature is 300 K,the initial pressure is 1bar,the optimal blocking ratio is about 0.84 when equivalence ratio from 0.6 to 1;the optimal blocking ratio is about 0.9 when the equivalence ratio is 0.4.(3)、When the initial temperature is 300 K,the equivalence ratio is 1,the optimal blocking ratio is about 0.84 when the initial pressure from 1bar to 3bar.the optimal blocking ratio is about 0.9 when the initial pressure is 0.6bar.(4)、When the equivalence ratio is 1,the initial pressure is 1bar,the optimal blocking ratio is about 0.84 when the temperature is 300K;the optimal blocking ratio is about 0.9 when the initial temperature is from 350 K to 450 K.Thirdly,this paper selects different radius with same blockage ratio as turbulence parameters,By changing the initial pressure,equivalence ratio and initial temperature,the schlieren images and the pressure data of the upper and lower combustion chamber are obtained,which are utilized to select optimal parameter of disturbed device.By analysising the flame propagation speed,combustion duration and the rate of change of combustion duration,we can find out:(1)、When initial condition is constant,there is a best radius with same blockage ratio,the combustion duration is shortest.(2)、When the blockage ratio is 0.84,the initial temperature is 300 K,the initial pressure 1bar,the optimal redius is about 5mm when equivalence ratio is from 0.6 to 1;the optimal redius is about 4mm when the equivalence ratio is 0.4.(3)、When the blockage ratio is 0.84,the initial temperature is 300 K,the equivalence ratio is 1,the optimal redius is about 5mm when the initial pressure is from 0.6bar to 3bar.(4)、When the blockage ratio is 0.84,the initial pressure is 1bar,the optimal redius is about 5mm when the initial temperature is from 300 K to 450 K.