柴油机气缸盖传热规律研究
Heat Transfer Investigation on a Diesel Engine Cylinder Head
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摘要: 利用Star CCM+软件,采用多面体网格技术和基于流体体积函数方法(VOF)的两相流沸腾模型,对单缸柴油机气缸盖的冷却传热进行了流-固耦合仿真计算,通过气缸盖的测试温度对仿真结果进行了校验. 在此基础上,对气缸盖的传热规律进行了研究. 研究表明,单缸柴油机负荷增加时,气缸盖冷却水壁面排气门鼻梁区的传热系数HTC呈现出在较小负荷增加迅速,在较大负荷增加变缓的规律;气缸盖向冷却水传递的热流量则随单缸柴油机负荷的提高呈现出加速上升的趋势,转速为2000 r·min<sup<-1</sup<时,单缸柴油机功率由44kW增加到61kW,气缸盖传递给冷却水的热流量增幅为31.4%;功率由61kW增加到80kW,气缸盖传递给冷却水的热流量增幅为61.3%.Abstract: Employing the polyhedral grid technique and based on the volume of fluid (VOF) two-phase flow boiling model, the heat transfer simulation of fluid-structure interaction for a diesel engine cylinder head was accomplished using Star CCM<sup<+</sup< software. The tested temperature of the cylinder head proved the validation of simulation results. Then, the heat transfer regularity of the cylinder head was studied. The results show that, when the load of the single cylinder diesel engine increases, the heat transfer coefficient (HTC) of the bridge between the exhaust valve ports of the cylinder head wet wall increases quickly at lower load but it increases slowly at higher load. The heat flow through the cylinder head increases rapidly with the increase of the load of single cylinder diesel engine. The tested data indicated that, under the rotating speed of diesel engine at 2000 r·min<sup<-1</sup<, the heat flow through the cylinder head could be increased by 31.4% while the power increasing from 44kW to 61kW and it could be heightened by 61.3% while the power increasing from 61kW to 80kW.
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