Experimental Study On Vapor And Liquid Spray Characteristics Of Diesel-n-pentanol Blends

With the shortage of petroleum resources and the requirements of national emission regulations,the main way to solve this problem is to find a biomass oxygenated fuel which can replace diesel.Compared with other alcohol fuels such as methanol,ethanol and butanol,n-pentanol has the advantages of high energy density,high latent heat of vaporization,good mutual solubility with diesel and easy storage and transportation.It is regarded as the most promising alternative fuel for diesel fuel in the 21st century.Because of the spray characteristics and evaporation characteristics of the fuel and the mixing process of the fuel and the air from the nozzle have an important influence on the combustion and emissions of the diesel engine,it is necessary to study the vapor-liquid spray characteristics of the diesel/n-pentanol mixed fuel.It will provide a basis for the feasibility of using n-pentanol as a substitute fuel for diesel engines in the future.In this paper,the techniques of High speed photography and schlieren images were used to study the vapor and liquid phase spray characteristics of different blends of diesel and n-pentanol at different ambient temperatures(573,623,and 673 K)and injection pressures(80,120,and 160 MPa)in this paper.The studied blends consisted of pure diesel(0%PODE3-4;Note:all percentages are vol%unless otherwise specified)(PO)and the mixtures containing 20%(P20)and 50%(P50)n-pentanol.The results show that,with the proportion of diesel blended n-pentanol increases,the vapor phase cone angles,projected area and mass of entrained air of the three fuels increase.However,liquid phase cone angle,penetration distance,projected area and mass of entrained air decrease.The vapor phase penetration distances of P0 and P50 are substantially coincident before 0.8 ms,and increase after 0.8 ms as the blending ratio of the mixed fuel increases.The injection pressure increases,the vapor phase cone angle,vapor phase penetration distance,vapor phase projection area and vapor phase mass of entrained air of the three fuels increase,and the liquid phase cone angle of P20 and P50 also increases,but the liquid cone angle of P0 has no consistent rule to follow.the injection pressure increases,the P0 liquid projection area and liquid mass of entrained air increase,but the liquid-projected area and mass of entrained air of P20 and P50 has no consistent rule to follow.Increasing the diameter of the nozzle hole,the vapor-liquid phase penetration distance,projection area and mass of entrained air of the three fuels are increased,but the vapor cone angle is decreased,and the liquid cone angle of P20 and P50 is increased.However,the P0 liquid cone angle does not change uniformly.When the ambient temperature increases,the vapor cone angle,vapor phase projection area and vapor phase mass of entrained air of the three fuels increase,and the liquid phase cone angle,liquid phase penetration distance,liquid phase projection area and liquid phase mass of entrained air are all reduced.In addition,the P50 vapor phase penetration increases as the ambient temperature increases,but the PO and P20 vapor phase penetration decreases as the ambient temperature increases.