The Investigation Of Heat Transfer Performance Of New-type Highly Efficient Grooved Heat Exchanger

As the world resources decreasing and energy costs increasing, highly efficient heat exchanger plays a more and more important role in the development of modern marine shipping. Thin film evaporation is a passive strengthen heat transfer technology, and most of the heat transfer through the thin film of regional. This paper, based on the thin film evaporation principle, designed a highly efficient grooved heat exchanger, analyzed the working principle of the new-type highly efficiency grooved evaporator, established the thin film evaporation mathematical model in the groove structure, and analyzed the factors of influencing thin film evaporation. The conclusion shows:the heat flux increase rapidly and then drop down slowly from non-evaporating area to intrinsic meniscus in the thin film evaporation. The parameters of groove such as the width, depth, base angle affect the heat flux through thin film evaporation region. At the same time, in order to test the capability of the conventional heat exchanger and grooved heat exchanger experiment respectively, this paper set up a small steam condensing refrigeration system. The experimental results show: whether in the evaporation conditions or in the condensing conditions, the heat transfer capability of the grooved heat exchanger is better than that of the conventional heat exchanger. In the evaporation conditions, the most greatly improve rate of the total heat transfer coefficient is15.11%, and the most greatly improve rate of internal heat transfer coefficient is65.07%. In the condensing conditions, the most greatly improve rate of the total heat transfer coefficient is7.34%, and he most greatly improve rate of internal heat transfer coefficient is15.48%.The result demonstrate that:by changing the structure of the inner tube to form the axial grooves, it is beneficial to form thin film evaporation, so as to increase the thermal efficiency. The investigation of this paper is conducive to further thin film heat transfer enhancement technology.