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采用了剪切应力输运(SST)k-ω两方程湍流模型并考虑近壁低雷诺数的修正对矩形横截面螺旋管内冷却水流动和传热特性进行了数值研究。数值分析了在不同入口雷诺数、曲率半径以及扭距条件下,螺旋管内的温度、速度场以及流线的变化,讨论了螺旋管内、外壁面对流传热系数的差异及产生机理,同时与直通管道传热性能进行了比较。研究发现由于离心力的作用,螺旋管内存在显著的二次流动,管内、外侧壁面对流传热存在差异。旋转一周后,螺旋管即进入了流动稳定状态,入口雷诺数可以显著提升螺旋管整体的对流换热效率,扭矩和曲率对内外壁面传热效果的影响不大,而窄高型的横截面构型可以显著改善螺旋管的传热效果。研究结果对应用矩形横截面螺旋管的冷却设计提供参考。
A numerical simulation of the flow and heat transfer characteristics of the cooling water in a rectangular cross section spiral tube was carried out by using turbulence model of shear stress transport (SST) k-ω two equations and considering the low Reynolds number of the near wall. The temperature, velocity field and flow line in the spiral tube under different inlet Reynolds number, radius of curvature and torque were numerically analyzed. The differences and mechanism of convective heat transfer between the inner and outer wall of the spiral tube were discussed. Pipe heat transfer performance was compared. It is found that due to the centrifugal force, there is a significant secondary flow in the spiral tube, and there is a difference in convective heat transfer between the inner wall and the outer wall. After one revolution, the spiral tube enters into the flow stable state, and the inlet Reynolds number can significantly improve the overall convective heat transfer efficiency of the spiral pipe. The torque and the curvature have little effect on the heat transfer effects on the inner and outer wall surfaces, while the narrow cross-sectional structure Type can significantly improve the heat transfer effect of the spiral tube. The results provide reference for the cooling design of rectangular cross-section spiral pipe.