板翅式换热器微通道内汽化相变过程的数值模型

Numerical Model of Flow Boiling Process of Refrigerant in Microchannel of Plate-fin Heat Exchanger

为了定量描述板翅式换热器相变换热特性进而优化换热器结构,本文建立了板翅式换热器冷流体侧汽化相变过程流动与传热的数值模型。本文首先分析流动过程中的流型变化过程以及传质过程;通过模拟计算两相流动过程中粘性力、表面张力、剪切力、重力,实现泡状流、环状流、雾状流等不同流型的模拟;通过质量守恒定律建立汽化相变过程中的传质模型,计算得到传质速率,同时得出潜热传热速率。基于提出的模型,对不同传热工况下对汽化相变传热、传质性能的影响进行了分析。

To predict the performance of heat exchangers and to optimize the structure of plate-fin heat exchanger,a numerical model of plate-fin heat exchanger to predict the process of heat transfer and mass transfer is established.The flow and mass transfer mechanism of two-phase flow were analyzed.Then,a model for simulating flow pattern,including bubble flow and annular flow and mist flow,is developed with force analysis.The mass transfer model and latent heat model are developed based on mass conservation law,to predicte the transfer rate and latent heat rate of evaporatation.Based on the proposed models the heat transfer and flow patterns are analyzed under different operation conditions to discuss the effect on performance.