倾斜圆管内超临界 RP-3流动换热特性数值研究 *

Numerical Studyon FlowandHeat Transfer Characteristics of Supercritical RP-3in Inclined Tubes

关键词:  超临界  RP-3  倾斜圆管  二次流  换热中图分类号:V312+.1

Key words:  Supercritical  RP-3  Inclined tube  Secondary flow  Heat transfer

摘要:

采用数值模拟方法对倾斜圆管内超临界 RP-3的流动换热特性进行研究，以获得倾斜角度对流动换热的影响规律及作用机理。物性参数由 RP-3的四组分替代模型获得，湍流模型选择 LS低雷诺数 k-ε模型，通过计算结果与实验数据的对比保证计算方法的准确性。分析倾角为 45°的圆管内壁温轴向及周向分布变化规律，发现浮升力引起的截面内二次流与热加速效应分别导致两次壁温峰值的出现，而质量流量由 0.3g/s增加至 0.9g/s过程中，浮升力作用效果减弱，湍流强度增大，两次峰值先后消失；在垂直流向与沿流向浮升力综合作用下， -90°～90°不同倾角管内表现出不同换热规律。

Abstract:

In order to obtain the effects of inclination on flow and heat transfer characteristics of supercriti. cal RP-3，numerical study in inclined tubes with a four-species surrogate model of RP-3 and LS low Reynolds number k-ε turbulence model was carried out. The results were compared with experimental data to guarantee theaccuracy of numerical method. Wall temperature distributions of 45° inclined tube in longitudinal direction andcircumferential direction were analyzed and two peaks were attributed to the secondary flow caused by buoyancyforce and the thermal acceleration. When increasing the mass flux from 0.3g/s to 0.9g/s，the effect of buoyancyforce weakened and the turbulence enhanced which resulted in the disappearance of two peaks. Different heattransfer regularities appeared at different angles from -90° to 90° on account of the distribution of buoyancy forc.es that’s perpendicular to the flow direction and along the flow direction.