Numerical Simulation On Spray Characteristics Of Ethanolin The Cylinder

The problem of energy crisis and environmental pollution become more and more serious, renovations in the traditional energy technology are being focused. As a main energy consumer and the main emission source of pollution, the automotive engine faces double stresses as energy saving and environment protection. In order to reduce the independency of the oil resource, develop the alternative fuels is imperative under the situation. Alternative fuel ethanol in the engine has a history, which is an oxygen fuel and the theory air and fuel ratio is comparatively low, and the comparatively low boiling point makes it be easy to evaporate, so it can be combustion completely in the engine,so it reduces the emission and pollution to air. Ethanol is a green renewable clean fuel, with the development of science and technology,which is a rich source, and can be obtained from grain and plants,and the production of burning ethanol emission to the atmosphere can be consumed by occurring plant photosynthesis, reduced the greenhouse effect. As an alternative fuel of the engine,ethanol is used widly, relaxing the both problem of oil shortage and environmental pollution .Ethanol is considered the one of most considerable alternative fuels.The AVL-Fire-software of using in internal-combustion engine is employed to simulate the transient spray characteristic of ethanol,in this paper review of the application of ethanol at home and abroad.Introduced the spray atomization theory and some basic-phenomena about spray during fuel is injected,and reported the model of simulate the spray process,the control equation of Fluid dynamics,and the detailed steps to simulate the process of ethanol spray. Creat the moving mesh model and in order to make a successful simulation,suitable physical models and the boundary conditions was decided.Then had a detailed analysis about the simulation results of ethanol and diesel,the comparative results shows that:ethanol spray shape is a little shorter and wider than diesel's,and spray cone is a little bigger than diesel's,and the pentration and SMD both are smaller than diesel's.Ethanol has a high vapouration thermal energe, so the temperature field of ethanol and diesel have a different chage.the firest one's chage is obvious than the second one.Ethanol spray capability is well and the saturation vapour concentration is higher than diesel's.The author also studied the different factors which maybe influence pentration and SMD of ethanol.The study results show that:increasing the size of nozzle hole can shorten the pentration and enlarge the SMD;increasing the temperature of ethanol fuel can shorten the pentration and SMD;increasing the initial spray cone can shorten the pentration and lower the SMD.