High-Performance Impingement-Based Ultracompact Heat Exchanger

Significant advances have been made in compact liquid-liquid heat exchangers in the recent past, such as the brazed plate heat exchanger with enhanced plate geometries. However, additional improvements in heat exchanger performance may be realized by incorporating impinging jet flow rather than flow parallel to the heat exchange surface. It has been recognized for some time that highly efficient heat transfer over large areas can be attained using impinging jets with nearby drains, but no design model is available for this configuration. This paper presents a relatively simple theory for the heat transfer performance of jet-drain arrays based on the concept of transient heat transfer to the liquid. This theory is verified by comparison to experimental data. Next, the design and implementation of a liquid-liquid heat exchanger based on jet-drain arrays is presented and the performance of this novel device is directly compared with that of a brazed-plate heat exchanger. In addition, computational fluid dynamics simulations are used to design an enhanced impingement plate that virtually eliminates interactions between neighboring jets, further improving performance. Using the theory developed in this paper, very high performance compact liquid-liquid heat exchangers can be designed with relatively large orifices (approx. 1 mm), allowing for low pressure loss and the ability to pass a significant amount of solids through without clogging.Copyright © 2007 by ASME