【摘要】 废气再循环（EGR）技术是当下降低柴油机NO_x排放的有效手段，EGR冷却器的换热效果对EGR系统的综合性能起到关键作用。以EGR系统中的冷却器为研究对象，对其开展气液耦合换热仿真研究。通过气液耦合方法对EGR冷却器的换热过程进行三维数值模拟，建立了4种不同的典型气液耦合换热模型，由气液耦合计算得到典型换热模型中高温废气和冷却水之间的传热关系。借助已搭建的气液耦合换热模型，开展分析研究，探讨管道截面几何形状及表面凹槽对冷却器综合性能的影响。结果表明：扁管冷却器的换热效果好于圆管，带有凹槽的改进结构能够有效提高换热效率。在4种模型中，扁管凹槽模型的换热效果最为出色。更多还原

【Abstract】 Exhaust gas recirculation(EGR) technology is currently an effective measure to reduce NO_x emissions from diesel engines, and the heat exchange effect of the EGR cooler is crucial to the comprehensive performance of the EGR system. This paper takes the cooler in the EGR system as the research object, and carries out the simulation study of its gas-liquid coupling heat exchange. Based on the gas-liquid coupling method, a three-dimensional numerical simulation of the heat exchange process of the EGR cooler is investigated. Four different typical gas-liquid coupled heat transfer models are established, and the heat transfer relationship between the high-temperature exhaust gas and the cooling water in the typical heat transfer model is obtained from the gas-liquid coupling calculation. Based on the established gas-liquid coupled heat transfer models, the effects of the cross-sectional geometry and surface grooves of the tubes on the comprehensive performance of the cooler are analyzed and studied. The results show that the heat transfer effect of the flat tube cooler is better than that of the round tube, and the improved structure with grooves can effectively improve the heat transfer efficiency. The flat tube groove model has the best heat transfer effect among the four models.更多还原