Study On Spray Characteristics Of Two-Component Fuel With Different Mixing Ratios

With the miniaturization of the engine,the engine intake pressure is increasing,the fuel injection manifold after the pressure booster up to 150 kPa or more,so lowpressure spray environment faces challenges.There is an urgent need to find a way allow higher back pressure spray flash boiling.In this paper,isopentane and undecane act as the reference fuel(isopentane as low boiling point fuel,undecane high boiling point fuel).With isopentane volume ratio gradually increased,four different ratio of mixed fuel were made.The distillation characteristics of pure and mixed fuels were tested,and the flash boiling characteristics of mixed fuel and superheated jets were studied.The mechanism of mixed fuel flash-boiling was revealed.The results show that the mixed fuel is boiling in a certain temperature range to produce distillate.The distillation curve is a three-stage curve with the evaporation temperature changing constantly.When the proportion of low boiling point fuel increases,the average volatility increases.When the mixed oil is heated,the low-boiling components evaporate ahead of the high-boiling components.By comparing the morphology of the single oil-spray,it is shown that the higher the ?,the more intense the spray crushing,the more obvious the change of spray expansion and penetration.The higher the oil pressure,the more obvious the spray change.The results show that the single-hole spray low-boiling point fuel evaporation mainly occurs on the side of the spray,which causes the expansion of the spray.The spray distance is mainly controlled by the high boiling point fuel.Pa/Ps contains two components under the evaporation,so mixed fuel in the case of high superheat flash boiling degree is not the same,the higher the proportion of low boiling point fuel,the stronger flash boiling degree.The effects of low boiling point fuels on spray flash boiling were studied under different influencing factors.The higher the oil temperature,the lower the back pressure,the stronger the promoting effect.The tests of different components of fuel under different backpressure show that the addition of low boiling point fuel is an effective way to achieve high back pressure spray flash boiling.In addition to accelerating the evaporation of the liquid fuel,the low boiling point fuel acts on the porous spray to enhance the interaction between the fuel plumes.And with the oil temperature rise,the role of low boiling point fuel is more obvious.