3-Phase Coupling Heat Transfer And Stress Analysis Of A Plateau Diesel Engine

With the development of the western region of China, the plateau transportation capacity has become the key point of development. Diesel engine as the core of heavy truck also need to adapt to the plateau environment, to contribute the plateau economic development. As a branch of the adaptability of plateau, diesel engine's thermal balance capability has attracted more and more attention. The characteristics of low pressure and low temperature in plateau area have a strict requirement for diesel engine's cooling system. All kinds of experiment and numerical simulation method of the thermal management of plateau diesel engine has become an indispensable means to develop and design the cooling system of plateau diesel engine.Based on a 12-cylinder plateau diesel engine, this paper assessed cooling system's flow and heat transfer capability by using FLUENT. Then combining with ANSYS Workbench statics analysis module, simulated single cylinder head thermal mechanical coupling stress distribution.Begins with an analysis of the high altitude cooling water parameters change, and for four different altitudes selected corresponding concentration of ethylene glycol solution as the altitude's cooling medium, made adiabatic flow simulation for the whole water jacket. And compared the simulation results and testing data in 2000m. Then selected the worst cooled cylinder, No.6 cylinder in 5000m altitude, and built up the cylinder head-water jacket-cylinder liner fluid-solid coupling system to investigate heat transfer capacity. Then innovatively added the intake and exhaust into the system, which realized gas-fluid-solid 3-Phase coupling heat transfer. Then compared the temperature distribution with or without intake and exhaust, which suggested the cylinder head's temperature distribution with intake and exhaust was closer to practical situation. Then for poor local water jacket flow put forward structure improvement, made 3-Phase coupling simulation again, and found after improved the flow of stretch out structure was been activated, cylinder head temperature of corresponding position decreased. Finally, made thermal-mechanical coupling simulation for the improved cylinder head by using ANSYS-Workbench and acquired stress distribution. The results showed under the combine influence of imported thermal load, mechanical load and assembly constraints, the stress of cylinder could meet with the strength requirement.