Research On Coupling Model Of Diesel Engine Thermodynamics And Thermal Resistance And Heat Capacity

Because of its high efficiency,good economy and power performance,diesel engine has been widely used in transportation,agriculture,military and many other fields.The heat transfer problem of diesel engine is one of the main factors that affect the development of diesel engine performance.Among them,the heat balance research of internal combustion engine is the most important,which occupies a very important position in the design of diesel engine.In this paper,a calculation program based on thermodynamic model and thermal resistance heat capacity model is developed to study the heat transfer of diesel engine.In order to study the heat distribution of fuel combustion heat release in various heat transfer channels of diesel engine,and to explore a fast prediction method of component surface temperature,this paper takes 110 single cylinder diesel engine as the research object,and establishes the heat resistance heat capacity heat transfer network model of diesel engine including cylinder head,cylinder liner,piston and other main components according to the actual structure of diesel engine,and compares with the existing thermodynamic model The coupling model of diesel engine thermodynamic model and thermal resistance heat capacity model is established.Using the coupling model of thermodynamics and thermal resistance and heat capacity to simulate the heat transfer of a single cylinder engine,the surface temperature of the main components of the diesel engine combustion chamber and the heat transfer in various ways can be predicted.Three dimensional software was used to simulate the heat transfer in the cylinder to calibrate and verify the calculation results of the coupled model.On this basis,the thermal resistance and heat capacity model is deeply studied,and the influence of increasing the number of nodes on the model is analyzed.On the basis of the thermodynamic and thermal resistance heat capacity model,the change of heat transfer process in cylinder of diesel engine before and after adding heat insulation material is explored,and the application prospect of the coupled model in fast calculation of low heat dissipation diesel engine is analyzed.The results show that: the coupled model of thermal resistance,heat capacity and thermodynamics can expand the practicability of the model,and can provide theoretical guidance for the study of heat balance and the rapid prediction of component surface temperature of diesel engine;based on the coupled model,the heat transfer process of the diesel engine before and after heat insulation is calculated,and it is found that the heat dissipation in the cylinder of the diesel engine is reduced by 5.2% after heat insulation The results show that the temperature of the coating surface is higher than that of the wall before heat insulation;the air intake in the cylinder is reduced by 1.06%;the maximum explosion pressure is increased by 12.24 bar,increasing by 6.27%;the maximum temperature is increased by 36.6k,increasing by 2%compared with that before heat insulation.