某型号摩托车发动机冷却水套设计及改进研究

Research on Design and Improvement of Cooling Water Jacket for a Certain Type of Motorcycle Engine

针对某型号摩托车发动机冷却水套模型,采用计算流体力学( Computational Fluid Dynamics,CFD )分析方法对该冷却水套的冷却性能进行分析,分析结果表明现阶段的此款水套设计存在排气口侧温度偏高,流速偏低,缸体和缸头位置压差大,压损严重的问题。通过理论计算表明缸体和缸头水套间的通道大小对其附近的流场影响很大,直接影响冷却性能。在此基础上对现有模型进行仿真优化,计算并调整靠近排气口的通道孔尺寸和位置,仿真结果表明修改后的水套实现了流速均匀,水套内温度分布均匀合理,进出口最大压差下降,压损得到改善,避免了水套内流动死区的存在;且分析改进后水套模型的散热性能和阻力系数表明优化方案满足初始散热要求,并能降低冷却水套内流动阻力损失,降低水泵的耗功,提高发动机的动力输出。

For the cooling water jacket model of a certain type of motorcycle engine, the cooling performance of the cooling water jacket was analyzed by Computational Fluid Dynamics analysis method. The analysis results show that the water jacket design at this stage has problems that the temperature on the exhaust port side is high, the flow rate is low, the pressure difference between the cylinder block and the cylinder head is large, and the pressure loss is serious. Theoretical calculations show that the channel size between the cylinder and the water head of the cylinder head has a great influence on the flow field in the vicinity, which directly affects the cooling performance. On the basis of that, the existing model was simulated and optimized, and the size and position of the channel hole near the exhaust port were calculated and adjusted. The simulation results show that the modified water jacket achieves uniform flow velocity, uniform temperature distribution in the water jacket, and the maximum pressure difference between the inlet and outlet is reduced, the pressure loss is improved, and the existence of the dead zone in the water jacket is avoided;The improved the heat dissipation performance of the cooling water jacket model and drag coefficient meet the initial heat dissipation requirements, and can reduce the flow resistance loss in the cooling water jacket and the power consumption of the pump, and can improve the power output.