Heat Transfer And Friction Characteristics For Crossflow Over Staggered External Three-dimensional Finned Tube Banks

In this paper, the influence of geometric parameters of fins on the characteristics of heat transfer and friction for crossflow over staggered new external three-dimensional finned Tube banks invented by Chongqing university (B section) of China are investigated by means of comparative experiment and optimal experiment. The working fluid is air. The result of experiment show that the new external three-dimensional finned Tube not only enlarge the effective area of heat transfer ,also enhance the heat transfer within air and tubes . In the range of experimental Reynolds numbers Re=2900～14000,the ratio of enhancement of heat transfer is from 1.5 to2.5 and the ratio of pressure drop increasing is from 1 to 3.5 compare to bare tubes. The result of experiment manifest the thermal characteristic of the new external three-dimensional finned Tube is sufficient. In addition, the result of experiment show that the numbers of Nu and Eu increase with the altitude of fins and reduse with the space between fins. The influence of width of fins on Nu and Eu is not obvious.The heat transfer and friction factor correlations are obtained by step-by-step regression, and the efficiency of this correlations are specialized, which supplies some theory bases for engineering use, optimal geometric parameters of fins, and after experiments...