卧式柴油机冷却水流动特性的影响因素研究

针对卧式柴油机强制冷却闭式循环系统水套结构,试验研究了不同工况下水套入口流量及关键点的温度和压力。采用计算流体动力学(CFD)三维模拟的方法建立了冷却水流动仿真模型,并进行了试验验证。设计了冷却水套结构参数正交方案,通过CFD模拟分析了水泵出水流量、公共水腔截面形状和面积、缸体及缸盖入水孔的设置和分布等水套结构参数对冷却水流动的影响关系。研究结果表明:卧式柴油机缸体入水孔截面积和布置对缸体水套冷却水流动、冷却效果和冷却均匀性有很大的影响;卧式柴油机缸盖入水孔的位置、孔数和截面积等结构参数对缸盖水套的冷却水流动、冷却效果、冷却均匀性及进/排气侧的冷却分布等均有很大的影响。

Influence Factors on Coolant Flow Characteristics in a Horizontal Diesel Engine

According to cooling water jacket structure features of forced closed-loop cooling system in horizontal diesel engine,its cooling water flow rate,temperature and pressure at inlet and several critical locations of the cooling water jacket in different conditions were measured and analyzed.A numerical simulation model of coolant flow was built up by using three-dimensional computational fluid dynamics(CFD) simulation method and was verified with the measurement data.The orthogonal scheme of cooling water jacket structural parameters was designed based on design of experiments(DOE),and impacts of the structural parameters,e.g.water pump discharge,cross-section shape and size of shared water chamber,water inlet hole arrangement of cylinder block and cylinder head on coolant flow were investigated.The results indicate that for horizontal diesel engine,cylinder block water inlet hole arrangement and cross-section area greatly affect the coolant flow characteristics,cooling effect and cooling uniformity for its water jacket,and cylinder head water inlet hole location,number and cross-section area have great influence on the coolant flow characteristics,cooling effect and cooling uniformity and cooling water distribution between intake port side and exhaust port side in its cooling water jacket.