柴油机机体-冷却水套流固耦合系统传热仿真

Simulation of heat transfer by liquid-solid coupled method of engine block and cooling water jacket

为了改善发动机热负荷高这一现代发动机发展的主要障碍,该文就算例柴油机的机体及冷却水套作为耦合系统,采用流固耦合的方法实现整体耦合传热计算,从而将单独计算比较难确定的部分边界条件转变为系统的内部边界,在Fluent软件中进行数值计算。计算得到的收敛结果与采用热电偶法测量的机体及冷却水的温度试验数据较为吻合。根据机体及冷却水温度场分布,对机体和水套结构作适当改进来增加冷却水套的降温效果,再次做耦合系统的传热计算,发现A、B2种改进方案较原模型相比分别将机体最高温度降低到了152℃和122℃,验证了结构改进的合理性,最终有效地改善了发动机热负荷。

Nowadays,the problem of thermal load of engine had become a main obstructor as it developed,which made it become an urgent issue.The heat transfer simulation in this paper could be achieved by adopting liquid-solid coupled algorithm which was applied to engine block and cooling water jacket,consequently,the boundary conditions which were difficult to confirm when simulating separately were transformed into internal boundary conditions,then the heat transfer simulating was carried out by the Fluent software.The convergent results were consistent with the data measured by thermocouples in cylinder block and cooling water jacket.Based on the temperature distribution of the calculation,some improvements on the structure of engine block and water jacket were made to enhance the cooling performance.The numerical simulation of heat transfer was done separately again,we found that the highest temperature of the two improved engine block model A and B was reduced to 152℃ and 122℃ when compared with the primary model,then confirmed the rationality of new designed structure.Finally,it effectively improves the thermal load of the engine.