内置组合转子换热管综合传热性能的数值模拟研究

Numerical Simulation Research of the Comprehensive Heat Transfer Performance of Tubes with Rotor Assembly Inserts

通过对光管、内置螺旋两叶片和内置加轴螺旋两叶片两种结构组合转子的换热管的综合传热性能进行了三维模拟,分析了换热管内部的流场、速度场、温度场以及压力场,得到了管内流体的阻力特性和传热特性.模拟结果表明,内置组合转子换热管内的三维流动复杂,且有较强的湍动程度;相同雷诺数条件下,装有螺旋两叶片转子和加轴螺旋两叶片转子换热管的努赛尔数分别比光管提高了（1.32～1.35）倍和（1.43～1.47）倍,但引起的管内阻力系数也分别比光管增加了（134.6～144.）8％和（126.5～134.8）％.可见,加轴螺旋两叶片转子对换热管内传热能力的提高更为显著,同时也产生了一定的管内阻力,为综合考虑传热和阻力两方面因素,引入了综合评价指标（PEC）.对两种转子的综合评价指标值进行对比,加轴螺旋两叶片转子的综合传热性能更好.

Through the three-dimensional simulation of the comprehensive heat transfer performance of tubes assembly with spiral two blades rotors and spiral two blades rotors with axle and the plain tube, flow field, velocity field, temperature field and pressure field of the heat exchange tube were analyzed here, and the flow and heat transfer characteristics were obtained. The simulation results showed that the three dimensional flow in the tube inserted with several rotors was very complex, and the turbulent degree was strong. Under the same Reynolds numbers, the Nusselt number of the heat exchanger tubes with assembled spiral two blades rotors and spiral two blades rotors with axle increased to （1.32-1.35） times and （1.43-1.47） times than the plain tube respectively. The friction factor of the heat exchanger tubes with spiral two blades rotors assembly and spiral two blades rotors with axle assembly increased （134.6-144.8）% and （126.5-134.8）% respectively. It was visible that the improvement of heat transfer in the tube by inserting spiral two blades rotors with axle was more significant, but some friction was produced at the same time. Considering both heat transfer rate and friction factor, the performance evaluation criteria（PEC ） was introduced. Comparing the two kinds of rotors＇ PEC, the comprehensive heat transfer performance of spiral two blades rotors with axle was better.