中文摘要：

采用二维轴对称不可压缩N-S方程,利用有限体积方法和SIMPLE算法,对不同母线型式的扩缩管对流换热特性进行了数值模拟。在给定入口速度、温度型线的条件下,分别研究了层流和湍流状态下均匀、线性、抛物线等三种典型入口型线对对流换热性能的影响。探索了不同母线型式对传热强化的影响,得到了对流换热随母线形状的变化规律。在给定的状态中得到了一个比较适当的母线外形,使得扩缩管的传热性能有所优化。

英文摘要：

Using the two-dimensional symmetric incompressible laminar N-S equation, a numerical study of heat transfer characteristics of diverging-converging tubes with different generatrices is carried out with the finite volume method and SIMPLE algorithm. Three typical velocity and temperature profiles are speci- fied at the inlet, i.e. uniform, linear and parabolic distributions. Effects of different inlet profiles and gen- eratrices of diverging-converging tubes on heat transfer enhancement characteristics are studied. Variations of laminar and turbulent convective heat transfer characteristics in these tubes with different generatrices are obtained. Under the given conditions, a more appropriate generatrix is obtained through optimizing the heat transfer performance of the diverging-converging tube.