Experimental and simulation study on the distributor design in plate evaporators

Abstract

The maldistribution of refrigerant in the plate heat exchangers exerts a significant influence on the heat exchange performance. The introduction of distributor enhances the refrigerant distribution and increases the heat transfer coefficient in the plate evaporator. In order to investigate the specific influence of distributor geometric parameters on the refrigerant distribution and the heat exchange performance of a plate evaporator, this study first tested the performance of eight plate evaporators with different distributor angle and hole diameter by performing experiments, and then established a refrigerant distribution model based on numerical calculation and CFD simulation to further illustrate the influence of distributor geometric parameters at the range of -180°∼180° and 0.5mm∼1.5mm, respectively. Results demonstrate that, the geometric parameters of distributor (angle, hole diameter) are the main factors influencing the refrigerant distribution, thus affecting the heat exchange performance of the plate evaporator. The overall heat transfer coefficient achieves the maximum around -90° and 90°. As a result, the recommended distributor angle for conditions in this study is 63°, with an increase on the overall heat transfer coefficient of 33.6% compared to the lowest at -162°. Besides, the optimal value of the distributor hole diameter needs to be designed according to the specific working conditions such as refrigerant mass flow, temperature, pressure and PHE geometry parameters, which is 1.1mm for the evaporation condition in this study.