Numerical Studies On Heat Transfer And Friction Factor Characteristics For A Spiraled Tube With The Decentration Design

As a result of energy shortages, the technology of strengthening the heat conductingability is always the key stone of research. Based on the synergy principle, the paperdesigns a new effective heat transfer tube, which is a spiraled tube with decantration andconduct Numerical simulation to study on the heat transfer and flow characteristics of thenew heat transfer pipe. The tube can be made by spiraling a circular smooth tube, while thediameter of its cross-section always is identical.First of all，sets up the geometric model and the mathematic model of the pipes fortransefrring heat. In order to analyze the heat transfer and flow characteristics, as well astheir overall performance, we simulated the heat transfer and flow of the model with theFLUENT software.Secondly, simulation results was sorted out. The results show that the decrease ofhelical pitch and increase of eccentric distance lead to heat transfer enhancement andfriction augmentation; the comprehensive performance gets better with the increase ofReynolds number and the highest PEC value is over3, the EEC value of somecomputational results is above1.3; the Nusselt number of the optimized spiraled tube is1~2.1times lager than that of bare tube; and friction coefficient of optimized spiraled tubeis1~1.5times lager than that of bare tube; EEC value reaches maximum on the specifichelical pitch and eccentric distance, and in the paper the ratio of specific helical pitch andeccentric distance ranges from30to60or70to100when EEC value reaches maximum.While maintaining identical pump power consumption, the heat exchange amount of theoptimized spiraled tube is1.2~1.3times lager than that of bare tube. If the tubes are used inshell-and-tube (heat) exchangers, the exchangers can have advantages of energy saving dueto the larger heat transfer capacity on identical power consumption, compact structure dueto self-braced heat transfer tube, elimination of extra baffles structure, and less cost due todisappearance of baffle plates. With the upgrading of manufacturing of the special heattransfer tube, it is expected that shell-and-tube heat exchangers are widely used in industrialapplication. Therefore, based on the synergy principle and the idea of reducing the flow resistance, we see that the overall hydrocyclone can improve the performance of heattransfer, and it also can restrain the development of the secondary flow and themulti-longitudinal vortex flow to reduce local resistance, so as to get the bettercomprehensive performance while maintaining identical pump power consumption.Finally, in this article we summarized the research work and provided a theoreticalguidance for the enhanced heat transfer tubes in industrial applications and the design ofheat transfer surface and heat exchangers.