发动机散热器传热及内部流动试验研究

Experimental study on heat transfer and internal flow of an engine radiator

为了揭示发动机散热器传热及内部流动特性,特选择465Q型发动机管带纵流式散热器为研究对象,以阐明其几何与物理参数及结构特征;同时建立散热器性能试验台,制订了自然对流传热及流动特性试验方案。在完成散热器自然对流传热和流动特性试验的基础上,得到内部流动流量qv与进出口压强差Δp和消耗功率P,以及雷诺数Re与散热量Q和压热效率η等的变化规律和性能曲线。通过数值分析拟合出压强差Δp和功率P经验计算公式,以及散热量Q和压热效率η与温度t1和雷诺数Re的约束方程式。试验结果表明,管带纵流式散热器层流散热效果优于湍流,进水温度越高散热效果越差,外部温度分布不均匀及常态下内部流动消耗功率只占发动机额定功率的0.006 5%。

In order to reveal the heat transfer and internal flow properties of an engine radiator, 465Q type longitudinal tube-and fin radiator was targeted, with its geometric and physical parameters and structural characteristics expounded. The radiator performance testing bench was set up, and the testing program was developed for natural convection heat transfer and flow properties. By completing the experiment of natural convection heat transfer and flow properties of the radiator, variation regularity and performance curves were obtained, including internal flow q., inlet and outlet pressure difference Δp, consumption power P, Reynolds number Re, heat sinking capacity Q and dissipation ratio η. Through numerical analysis, two equations were fitted： the empiric formula of pressure difference Ap and power P, and the constraint equation of heavsinking capacity Q and dissipation ratio η with temperature tland Reynolds number Re. The experimental results showed that laminar flow behaves better than turbulent flow in the heat radiation, heat radiation becomes worse with the increase of the inlet temperature, and uneven distribution of external temperature and normal internal flow consumption power only accounts for 0. 006 5 % of the engine rated power.