Improvements on Flow Distribution and Heat Transfer Performance of Plate-fin Heat Exchangers by Qusai-<i>S</i> Type Header Configuration

Abstract

In order to reduce flow maldistribution and enhance the heat transfer performance, an improved quasi-S-type header configuration of plate-fin heat exchangers is proposed. Based on the analysis of the fluid flow distribution, the results indicate that the outlet velocity of the conventional header is uneven. However, the qusai-S-type header not only effectively reduces the geometric mutation, but also extends the hydraulic path, which guides fluid to the two sides and thereby reduces the maldistribution. The qusai-S-type header was designed on the basis of the cubic curve (denoted as configuration B), Bézier curve (configuration C), or two semi-circular segments uniting with one-line segment (configuration D). Compared with the conventional header (configuration A), the maldistribution parameters for configuration B, C, and D decrease by 75.2–93.9%, 80–94.8%, and 78.4–94.3%, respectively. Yet, the power consumptions of them increase by 26.3%, 22.3%, and 42.3%, respectively. Besides, the effectiveness of the conventional plate-fin heat exchanger declines about 15.1% due to improper header configuration, while the decrease of effectiveness can be controlled within 2.0% using the improved header configurations. Therefore, the improved header configurations can effectively enhance the flow uniformity and the heat exchanger effectiveness, but with a low power consumption penalty.