水平强化涟漪纹管的管内冷凝换热实验研究

Experimental Investigation on Condensation Heat Transfer Characteristics of Horizontal Enhanced EHT Tubes

在对比光滑管的基础上对3种水平强化涟漪纹管(1EHT、2EHT-1、2EHT-2)的管内冷凝换热特性进行了实验研究。保持制冷剂低质量流速条件下,统一采用测试段外径12.7mm,内径11.5mm的强化管进行实验。实验选用R410A制冷剂为工质,质量流量为800~260kg·(m2·s)-1,测试段干度为0.9~0.2,入口压力对应饱和温度约为320K。测试结果表明:随着质量流量的增加,HTC和压降也都不同程度的增大。换热强化比相对光滑管提高1.3~1.95倍。1EHT管具有最好的传热效率,主要原因是增大界面湍流导致二次流产生等效果,而2EHT管管型两种表现相似的传热特性,3种强化管的摩擦压降比光管增强的幅度更大,损耗随着面积的增加而增加,因为强化管的坑深度起主要的影响因素,但三者都表现出比光滑管更加优越的传热特性。

The condensation heat transfer characteristics of three kinds of EHT tubes(1EHT,2EHT-1,2EHT-2)were investigated experimentally on the basis of the comparison of smooth tubes.Under the condition of keeping the low mass flow rate of the refrigerant,a test tube with a diameter of 12.7 mm and an inner diameter of 11.5 mm was tested.The experiment uses R410A refrigerant as working fluid,the mass flow rate is 60-240 kg·(m 2·s)-1,the test section is 0.9-0.2,and the inlet pressure is about 320 K.The results show that HTC and pressure drop increase with the increase of mass flow rate.The relative enhancement factor is 1.3-1.95 times as high as that of smooth tube,1EHT tube has the best heat transfer efficiency in the low mass flow,the main reason is the increase of interfacial turbulence leads to the two flow effect,and the 2EHT tube showed similar heat transfer characteristics,three enhanced friction pressure drop than the light tube enhanced tube a larger,because strengthening the pit depth tube from the main influencing factors,but the three are more superior than the heat transfer characteristics of tube smooth.