Modeling framework to predict two-phase flow distribution in heat exchanger headers

Abstract

Mini- and microchannel heat exchangers have the potential to drastically decrease the size and cost of thermal systems, but they often underperform because of flow maldistribution. Maldistribution can be particularly acute when a two-phase mixture enters a heat exchanger header, which is difficult to address because the flow phenomena in these situations are poorly understood. Experimental studies in recent years have attempted to gain a better understanding of the flow regimes and distribution in manifolds, but methods to predict distribution in multi-channel heat exchangers have been lagging. A new modeling approach, which predicts the liquid and vapor flow rates in each channel of a microchannel heat exchanger based on header flow patterns and component pressure drop, is presented here. The proposed model shows good agreement with previously reported experimental results, predicting most of the data within the experimental error.