正弦波形管综合性能模拟及实验

Experimental and numerical research on comprehensive characteristics of the sinusoidal tube

为了提高换热管的综合性能,针对新型结构的正弦波形管,以水为换热介质,采用数值模拟的方法对其传热和阻力特性进行了研究,模拟云图表明,正弦波形管的周期性结构能够引发二次流,加强了管内流体的相互掺混,减薄了热边界层,使传热热阻减小,达到强化换热的目的。将测得的实验数据和模拟结果进行对比,结果表明:在5000≤Re≤28000的范围内,正弦波形管的总传热系数随着Re数的增大而增大,比直管提高了24.7%~58.4%;在相同的工况下正弦波形管中的压降略大于直管,二者的压降相差22%~38%;同时,二者的阻力系数随着Re数的增加而减小,且正弦波形管的阻力系数下降更迅速。当Re数>13000时,相同条件下波形管的阻力系数相比于直管增加幅度在20%以内。综合考虑总传热系数和压降,正弦波形管具有更好的综合性能。

In order to improve the comprehensive performance of tube,heat transfer and resistance characteristics of a new type of sinusoidal tube were studied by numerical simulation using water as working fluid.The simulation indicated that secondary flow is caused by the periodic structure of the sinusoidal tube,which in turn strengthens fluid mixing,and reduces thermal boundary layer.As a result,heat transfer resistance is reduced and heat transfer enhanced.The measured data were compared with the simulation ones.Total heat transfer coefficient of the sinusoidal tube increased to24.7%-58.4%than that of the straight tube,with the Re from5000to28000.Under the same conditions,pressure drop in the sinusoidal tube was slightly larger than the straight tube.The difference between the two was22%-38%.At the same time,resistance coefficient of the two tubes decreases as Re increases while the sinusoidal tube decreases more rapidly.When the Re number is larger than13000,the resistance coefficient increment of sinusoidal tube is less than20%.Considering the total heat transfer coefficient and pressure drop,heat transfer performance of the sinusoidal tube is better.