The Optimization Analysis Of Auxiliary Fuel Heater For Heavy Duty Vehicle

Northern China is relatively cold in winter,which will cause car cold start difficult,serious engine wear,pollutants increased in the exhaust and poor comfort.As a heat source independent of the engine,Vehicle fuel heater can achieve engine warming up and cabin heating without starting the engine.The perfect solution to these problems makes the fuel heater very widely used and the related research more necessary.In this paper,spray-type fuel heater has been used as the research object,and the flow field and atomization combustion process of fuel heater were studied by means of numerical simulation and experiment.This article is divided in three sections.Firstly,the intake flow field of the fuel heater and the air flow in the combustion chamber were studied.In view of the combustion conditions,the combustion chamber flow field is complex,and not conducive to the analysis of the flow field,the cold state of the heater flow field has been simulated in this paper.The fuel heater is modeled using a 3D modeling software at a 1:1 ratio.In order to reduce the amount of useless calculations,the 3D model is simplified and the fluid flow path is extracted.The velocity,pressure and turbulence energy of representative section were analyzed by computational fluid dynamics software.The effects of these physical quantities on fuel atomization,combustion flame were analyzed.It is found that the transverse inlet has a decisive effect on the flow Pattern in the combustion chamber.In this paper,the different eccentricity of the transverse inlet was parameterized and simulated.It is proved that the transverse inlet is important to reduce the dead zone in the combustion chamber and suppress the formation of carbon deposition.Through the comparison of different eccentric flow field,the optimal eccentricity of transverse inlet is 12 mm.Secondly,the atomization and combustion process of the sprayed fuel heater were analyzed theoretically,and the structure of the fuel heater nozzle were modified to change the form of the simple tubing injection to make the fuel injection situation in accordance with the actual situation.In this paper,DPM and non-premixed combustion model was used to simulate the atomization and combustion of fuel.The temperature field,atomization performance and combustion products of fuel heater were analyzed by cloud and simulation data.The results show that the combustion process has the problems of bad atomization,severe post-combustion and "dead zone of combustion".It has been optimized by changing the nozzle position and the baffle structure.The numerical simulation proves that the two schemes can effectively solve the above problems,improve the heater combustion efficiency,and reduce pollutant emissions.Finally,the experiment setup of the fuel heater performance was designed and built,and the boundary conditions of the simulation process has been obtained.The simulation results were compared with the experimental results,which proves the accuracy of the simulation.The intake air temperature were studied by the experiment setup,and the influence of intake air temperature,and heater fuel consumption,combustion efficiency,heat transfer efficiency and pollutant discharge was obtained by the group experiment.