轴向通流旋转盘腔流动换热的数值研究

Numerical Study of Flow Structure and Heat Transferin Rotating Cavity with Axial Throughflow

关键词:  旋转盘腔  非稳态  轴向通流  流动不稳定性

Key words:  Rotating cavity  Unsteady  Axial throughflow  Flow instability

摘要:

为了探究旋转盘腔内的流动和换热规律，对轴向通流旋转盘腔进行了非稳态数值模拟，将计算结果与实验数据进行了对比，探究了流动不稳定性的发展过程，分析了盘腔内流动结构和盘面换热特性随旋转雷诺数的变化规律。结果表明:旋转引起的正旋涡从盘罩附近开始发展，随转速的增大而变大，挤压低半径区域的强迫对流区，最终扩展到整个盘腔，盘腔中轴面的涡对数与流动不稳定性的强度有关。上游盘和下游盘的高半径区域换热强度随转速的增大而增强，下游盘低半径区域的换热强度在低转速下由于冲击作用而较强，但该冲击作用随转速的增大而减弱，低半径区域的换热强度也就随之减弱。当旋转雷诺数增大到4.94×105时，下游盘低半径区域受到的冲击作用减小到可以忽略。

Abstract:

To explore the flow and heat transfer rules in the rotating cavity， the unsteady numerical simulation of the axial throughflow rotating cavity was carried out. The calculated results were compared with the experimental value. The development process of flow instability was explored. The change law of flow structure and heat transfer characteristics of the disks with Re_Φ were analyzed. The cyclonic circulation whose rotation direction is the same as the disk， caused by rotating create near the shroud， become bigger and compress the forced convection zone in the low radius area， finally expand to the whole cavity with increasing Re_Φ. The results show that the number of vortex pair in the cavity is related to the intensity of the flow instability. The heat transfer intensity at upstream disk and high radius area of downstream disk increase with increasing rotational speed， while the heat transfer intensity at low radius area of downstream disk decreasing because of the decreasing of the impact effect. When the Re_Φ increases to 4.94×105， the impact effect on the low radius area of downstream disk is reduced to negligible.