Experimental Study On The Heat Transfer And Pressure Drop Characteristics Of Turbulent Flow In Internally S-Like Finned Tubes

With the requirement of manufacture and science technology in recent years, the technique of enhancing heat transfer has been developed greatly, and has been widely used in many areas such as oil, chemistry, dynamic and refrigeration, and so on. It is necessary to investigate all kinds of questions about heat and mass transfer, which are used to design original and compacted heat exchanger.The characteristic of turbulent flow and heat transfer in tubes with two kinds of inside S-like fins were investigated on the base of experiment, and compared with that of smooth tube with the same diameter. On the basis of experimental data the corresponding correlations for the friction factors and Nusselt numbers vs. the Reynolds numbers for the fin-tubes were obtained. The results of the above fin-tubes were compared with that of the smooth tubes based on the Webb index.In the progress of tube wall temperature data computation, the numerical value analysis software—Fluent was adopted. Analyze the heat exchange effect of the fin-tubes from the inside flow field distribution.Using the Webb heat performance guide line, on the supposition that the pump power and the heat transfer area were the same, the results of the comparison between the inside S-like finned tubes and the smooth tube were :1. On the supposition that the pump power and the heat transfer area were the same, under the experimental scope of Re, the heat exchange ability of tube with single inside S-like fin was smaller than that of the smooth tube; when the value of Re is smaller than 50000 the heat exchange ability of tube with cross inside S-like fin was stronger than that of the smooth tube; and when the value of Re is bigger than 50000 the heat exchange ability of tube with cross inside S-like fin was less than that of the smooth tube.2. Under the experimental scope, the Q/Q_b curve of tube with single insideS-like fin increased with the value of Re increasing, which indicated that tube with single inside S-like fin had the stronger heat exchange ability underbigger value of Re; the Q/Q_b curve of tube with cross inside S-like findeclined with the value of Re increasing, which indicated that the increase of heat exchange ability was less than the increase of resistance, so that the whole heat exchange capability declined.3. Under the experimental scope, the heat exchange ability of tube with cross inside S-like fin was stronger than that of tube with single inside S-like fin.But the heat exchange increasing trend of tube with single S-like fin was bigger than that of tube with cross S-like fin, so that their heat exchange abilities were equal when the value of Re was 125000.The resistance coefficient/of tube with single S-like fin reduced with the value of Reincreasing, while the value of Re was bigger than 130000 the resistance coefficient hold the line basically; but the resistance coefficient of tube with cross S-like fin increased with the value of Re increasing. When the value of Re is smaller thanl 15000, the resistance coefficient of tube with cross S-like fin was smaller than that of tube with single S-like fin, but when the value of Re was bigger than 115000, the resistance coefficient of tube with cross S-like fin would be bigger than that of tube with single S-like fin.The results can be used in the designation and application of S-like inside finned tubes heat exchanger under the same condition.