内置开孔螺旋叶片转子换热管强化传热实验

Experimental study on heat transfer enhancement of tubes inserted with rotors with holes

以60%甘油水溶液为管程介质,对内置不同孔径开孔螺旋叶片转子换热管过渡区传热和阻力特性进行了实验研究。对光管性能进行了实验验证,以保证实验结果的可靠性。同时,对比分析了转子开孔孔径对其强化传热性能的影响,实验结果表明:内置S=0.375螺旋叶片转子换热管努塞尔数比内置S=0以及S=0.25螺旋叶片转子换热管的努塞尔数分别高出9.5%和21%左右,阻力系数高出9%左右。而对于综合性能而言,内置S=0.375螺旋叶片转子换热管的综合评价因子大于内置S=0螺旋叶片转子换热管的综合评价因子,内置S=0.25螺旋叶片转子换热管综合评价因子最小。综上可得,较大直径的开孔能提高转子的综合性能,但是较小直径的开孔反而会减弱转子的强化传热综合性能。

Experiments were conducted to study the heat transfer and friction factor of the heat transfer tube inserted with rotors with different holes. A 60%glycerin solution was used as tube-side working fluid in the transition region. In order to ensure reliability of experimental results,plain tube validation experiments were also conducted. Meanwhile,the effects of hole on heat transfer enhancement of the rotors were investigated. The Nusselt number of the tube inserted with S=0.375 rotors increased by 9.5%and by 21%than the Nusselt number of the tube inserted with normal rotors and rotors with hole of 3mm diameter respectively. Its friction factor increased by about 9%than the friction factor of the tube inserted with S=0 rotors and S=0.25 rotors. The PEC value of the tube inserted with S=0.375 rotors was the best,while the PEC value of the tube inserted with S=0 rotors was better than the tube inserted with S=0.25 rotors. The diameter of the hole had different impacts on the performance of the rotors. Big hole had a good effect,but on the contrary small hole weakened heat transfer enhancement.