Numerical Simulation Of Fuel Flow Of Diesel Nozzles And Spray Characteristics Based On Fluent

One of the most important working components of a diesel engine is the injector,whose performance directly affects the combustion process and emission performance of the diesel engine.The combustion of diesel fuel is determined by the good or bad atomization effect,and further affects the fuel economy and the dynamic performance of the diesel engine,which is of great significance for energy conservation and purification.Therefore,it is necessary to study the injection characteristics of the diesel fuel in the nozzle and the spray characteristics of the fuel.However,the space inside the nozzle is very narrow,and has a high fuel flow rate and injection pressure,which is very difficult to test.Therefore,through computer numerical simulation,the internal flow of the injector and atomization can be studied simply and effectively.The following are the main contents:In this paper,the high pressure common rail diesel engine nozzle was taken as the research object.The geometrical modeling of injector and spray field was carried out by CATIA software.Then the Gambit software was used for reasonable mesh division.Finally,the geometric model was imported into Fluent software.When numerical simulation of the fuel flow inside the nozzle was carried out,the mixed multiphase flow model was selected as its mathematical model.By changing the injection pressure,orifice diameter and nozzle taper,simulating the fuel flow velocity,pressure,turbulent kinetic energy and gas phase volume fraction distribution in the orifice,and different injection pressures,orifice diameters and orifices were drawn according to the simulation results.The average velocity of the taper at the exit of the nozzle was analyzed with time.The results showed that by increasing the injection pressure and the taper of the nozzle,reducing the diameter of the nozzle,the flow velocity the fuel inside the orifice can be increased.And increasing the injection pressure and the diameter of the nozzle,which was conducive to the occurrence of cavitation,but no cavitation occurred in the inverted cone.In the numerical simulation of the fuel atomization process,the simulation results of the nozzle outlet were first introduced into the spray field as the initial conditions,and the discrete phase model and the component transport equation were used to simulate the nozzle on the atomization characteristics of the fuel by changing injection pressures,diameter of thenozzle and the taper of the nozzle,and obtained the penetration distance,concentration and velocity profile of the fuel atomization,and the Sauter average of the oil droplets was plotted under different injection pressures,orifice diameters and nozzle taper.The curve of diameter with time was analyzed.The results showed that increasing the injection pressure and increasing the taper of the nozzle can increase the penetration distance of the fuel,reducing the diameter of the nozzle can increase the spray cone angle,the average diameter of the Sauter was reduced,which had an active on the fuel atomization.