进气温度对柴油-天然气双燃料发动机活塞温度及热变形的影响

Effects of Intake Air Temperature on Piston Temperature and Thermal Deformation in a Diesel-Natural Gas Dual Fuel Engine

基于ANSYS以WD615高压共轨柴油机为原型机建立了柴油-天然气双燃料发动机活塞温度场及热机耦合下变形场的分析模型。对不同进气温度下活塞温度场、变形场进行了研究,以改善活塞的热负荷及热机耦合下活塞的变形情况。试验结果表明:在标定工况下,进气温度为375K时,活塞第一环槽的平均温度超过230℃,活塞裙部的变形量超过活塞裙部与缸套间的正常间隙;同时缸内最大压力升高率增加,缸内爆震趋势增大。随着进气温度降低,活塞表面温度、活塞第一环槽的平均温度下降,活塞头部、裙部的变形量减少,活塞的温度及变形量都在合理的范围内,缸内爆震趋势减小。

A temperature and stress field under thermal mechanical coupled model on the piston of WD615 high pressure common rail diesel-natural gas dual fuel engine were established based on the ANSYS software. In order to improve the thermal load and stress of the piston, the changes of piston temperature field and stress field under different intake air temperature were analyzed. The result shows that intake air temperature was up to 375 K anomaly at the rated power, the average temperature of the piston top groove was over 230 ~C and the deformation of the piston skirt exceeded the normal clearance between piston skirt and cylinder liner. Meanwhile the max pressure rise rate and the knock trend in cylinder are increased. With the decrease in intake air temperature, the temperature of the piston top and piston top groove and the deformation of piston crown and piston skirt were decreased within a reasonable range. These show that controlling intake air temperature can improve the piston temperature and deformation field and optimize the combustion process.