Research on Surface Structure Optimization and Water Film Phase Change of Plate-Tube Evaporative Condenser

Abstract

To investigate the flow and heat transfer characteristics of a plate-fin evaporative condenser and to optimize its internal cavity structure, this study employs a combination of experimental methods and numerical simulations based on the commercial software Fluent. A mathematical model describing the gas-liquid two-phase flow is established, and the heat transfer performance of the heat exchanger is thoroughly examined. By comparing the experimental results with the simulation outcomes, good agreement is found in key parameters, which validates the accuracy and reliability of the numerical model. Based on this, the study analyzes the variation of the Nusselt number on the plate surface and the distribution characteristics of the water film under different Reynolds numbers. Consequently, the optimal cavity depth is determined to be H=2.0, and the optimal small diameter is D1=6mm. Under these optimal structural conditions, the influence of ten different inlet Reynolds numbers (ranging from 3500 to 13500) on the water film thickness is further investigated. The results indicate that as the Reynolds number increases, the water film thickness initially increases and then gradually tends to stabilize; that is, once the Reynolds number reaches a certain value, the growth rate of the water film thickness slows down significantly and approaches a constant value.