基于活塞热机耦合仿真的柴油-天然气双燃料发动机替代率研究

Research on Replacement Rate of Diesel and Natural Gas Dual Fuel Engine Based on Thermo-mechanical Coupling of Piston

建立了柴油-天然气双燃料发动机活塞、活塞销、连杆的有限元模型,分析了活塞在不同替代率下标定功率工况时的温度分布情况,将活塞上某些点处的仿真值与实测值进行了对比,误差满足工程要求。将温度场分布作为热机耦合的初始条件加载到活塞上,计算活塞热机耦合作用下的应力场和变形场。结果表明:活塞最高温度值出现在活塞顶部偏离燃烧室一侧,热机耦合的最大应力出现在销座内侧上部,最大变形值出现在活塞顶部偏离燃烧室的外侧,并随着替代率的增加而升高。

The finite element model of piston ,piston pin and connecting rod for diesel-natural gas dual fuel engine was estab-lished and the piston temperature distribution at rated power under different replacement rates was analyzed .The simulation values of some locations on the piston were compared with test values and the error between them could meet the engineering requirements .Using temperature filed distribution as Initial conditions of thermo-mechanical coupling ,the stress field and de-formation field of piston was calculated .The results show that the temperature at the top of piston in one side of combustion chamber is the highest .The stress of thermo-mechanical coupling in the upper position inside piston pin seat is maximum .The deformation at the top of piston outside of the combustion chamber was the most severe and increases with the increase of re-placement rate .