Study Of Heat Transfer And Pressure Drop Of Water Cut Oil In Tubes With Internal Fins

Recently because of process requirements and energy crisis, 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.Whereas the research method on heat transfer enhancement for the tube-side of the shell-and-tube heat exchanger has not been studied systematically for the fluid with low Reynolds number, especially water cut oil is the working fluid. The issue is carried out by numerical simulation and experiments in this dissertation. A new type of tube is firstly introduced, which can be manufactured directly by jointing multi-longitudinal fins on the nested smooth pipes. The new structure can enhance the convective heat transfer by the heat of internal and external sides. Meanwhile, the flow resistance is relatively low.In the Reynolds number range from 200 to 1200, the results of the numerical simulation are validated credible compared with that of the experiments.The Nusselt number and Fanning friction fitting criterion equations are obtained by analyzing and regressing 57 groups of experimental and numerical datas with Datafit. Also we have analyzed the impact of Reynolds number and the geometry sizes of tube on heat transfer and flow friction. In addition, through the analysis of Orthogonal Testing Method results, we can determine a tube with the best structure parameters,which is compared with the smooth pipe. Besides, we first find that there is an unsteadily zone of thermodynamic performance in transitional flow. In this zone, heat transfer augment ratio and resistance increment ratio will change acutely. The important purpose of detecting this zone is to provide some theories of choosing flowing state in engineering practice. Meanwhile, we have studied the influence of water cut ratio and steamy temperature on the performance of heat transfer and Finning friction. In all, the correlation equations of Nusselt number and flow friction factor are useful to put the new structure into practice.