柴油机冷却液流动及流固耦合传热研究-动力机械及工程专业论文 word格式.docx

理模型和数学模型,结合已知流体域的相关参数,施加合理准确的边界条件,得到了流
体在机体、缸盖以及两者连接部分的速度场,并通过进口处面积平均压力的监测,得到了进出口处的压力损失。
2)对无沸腾(非等温定常流动)时单缸柴油机缸盖水腔流固耦合传热进行分析, 分别对流体域和固体域选择合适的物理模型,根据以往的文献参考值确定合理的边界条件,得到了流体域和固体域的温度分布。
3)本文还探索了沸腾换热(非等温瞬态流动),加入了沸腾模型,重新对流体域物理模型及边界条件进行设置,得到流体域的温度分布图、VOF(Volume of Fluid)等值面压力分布图以及流体固体换热系数云图。
关键词:柴油机,冷却系统,流固耦合,沸腾
The Flow and Fluid-Solid Coupled Heat Transfer analysis of the Diesel Engine cooling system
Abstract
Flow and heat transfer problems of automobile diesel engine cooling system have been much concerned, which not only takes direct impact on the diesel engine cooling efficiency, load of the high-temperature parts, heat distribution and energy usage of the engine, but also affects the cooling uniformity in each cylinder, charging efficiency, oil and gas mixing, burning, flame propagation, heat transfer, pollutants generation, etc, especially for the high-enhanced multi-cylinder diesel engine. In the research of cooling fluid flow and heat transfer problems on diesel engine, it is difficult for us to get detailed information when using measuring instruments just because of plex structure of diesel engine. pared with experiment, taking 3-d numerical simulation method to solve flow and heat transfer problems can greatly reduce research cost, save resources, cut down the development cycle. Moreover, some results can be got which are regarded difficult or can not be measured. During the study of flow and heat transfer problems, traditional method is to calculate fluid and solid heat-transfer respectively, which requires constantly adjust the hypothetical boundary conditions during heat-transfer calculation. This process is more tedious, and there are certain disparities between calculation results and actual situation considering of the heat transfer condition inhomogeneity in the boundary solid-liquid on the condition. In addition, in diesel engine cooling fluid heat calculation, less consideration was taken about the boiling heat transfer.
Focusing on these prob