新型仿生结构强化管流动与换热性能数值研究

Numerical Study on Flow and Heat Transfer Performance of a New Type of Biomimetic Tube

本文以仿生结构强化管为研究对象,模拟研究了不同相对深度h/D和排列密度d^2/pl下的管内湍流的流动和换热性能,并与丁胞管进行了对比。结果表明,仿生强化管能够显著增加凸起附近流体径向分速度,增加流体的扰动,有效地增加了冷热流体的混合;在Re为1×10~4～4×10~4的变化范围内,换热增强因子Nu/Nu_0、阻力增强因子f/f_0及综合评价因子(Nu/Nu_0)/(f/f_0)的变化范围分别是1.11～2.13、1.49～3.72和0.45～1.13;低流速下,在传热综合性能评价图上位于4区,表明强化管具有良好的综合换热性能。最后,本文以无量纲参数相对深度h/D、排列密度d^2/pl以及雷诺数Re为变量总结出Nu数和阻力系数f的经验关联式,误差在10%以内。上述研究结果表明,仿生结构管在湍流情况下,具有良好的综合换热性能。

The turbulent flow and heat transfer performance of the biomimetic tube was numerically investigated with the non-dimensional parameters(relative depth h/D and arranging density d^2/pl)varied. Compared with dimpled tubes, the simulation results showed that the protrusion of the biomimetic tube increased the velocity magnitude in diameter direction and intensified the mixing of the fluids, which led to a better heat transfer performance. In the range of 1×10~4~4×10~4 for Re,the Nu for the enhanced tube was 11%~113% higher than that for smooth tube, while the friction factors was increased by 49%~272%. As a result, the performance evaluation factor of the biomimetic tube ranged from 0.45 to 1.13. At low flow rate, the working points are located in the region 4, which indicates an excellent heat transfer performance. Further, the empirical formulas for Nu and fwere respectively fitted in terms of the non-dimensional parameters(relative depth h/D, arranging density d^2/pl and Reynold number Re) with the errors within 10%. It was observed that the biomimetic tube could achieve profound heat transfer enhancement with acceptable pressure loss penalty.