增压柴油机整机耦合传热研究

An Analysis of Coupled Heat Transfer of Turbocharged Diesel Engine

传热研究对改善内燃机的工作过程、燃烧和排放有着重要的意义.采用试验测试与数值仿真相结合的方法,以一款非道路高压共轨柴油机作为研究对象,并基于试验测试结果建立了其整机耦合传热模型,分析了缸内各个关键零部件之间的热传递情况和温度场分布规律.研究结果表明:系统地考虑柴油机中各个零部件之间的传热问题,相比于传统的单个零部件传热研究,可以更加准确地确定边界条件,使得仿真计算结果更加接近实际;柴油机的缸盖鼻梁处温度较高,最高温度出现在第四缸鼻梁处;活塞的温度梯度较大,温差达到100℃左右,最高温度出现在活塞喉口靠近排气门一侧;第一道气环在环组中起到主要导热作用,三道活塞环温度由内侧向外侧呈递减趋势;缸套内壁面温度分布不均匀,轴向方向由上至下温度递减.

The study of heat transfer is of great significance to improve the working process,combustion and discharge of internal combustion engines. In this paper,one non-road diesel engine was used and the temperature field distribution of head,piston,rings and liner were studied by the method of combination experimental test and numerical simulation. The results show that,since components are regarded as a coupled system in this study,heat transfer simulation results with better accuracy is obtained,which agrees with experimental data. Radial and axial temperature of piston changes dramatically,and it showed a decreasing trend from top to bottom. In terms of ring set,most of the heat was conducted by top piston ring of the whole ring set,piston rings temperature decreasing trend from the inside to outside. The temperature of rings was unevenly distributed in the internal face,decreasing from top to bottom axially.