Effect of flow maldistribution on heat transfer performance and temperature field of plate-fin heat exchangers

Abstract

Plate-fin heat exchangers (PFHEs) are widely utilized in aviation precoolers, emphasizing not only heat transfer performance but also the outlet temperature distribution, with flow maldistribution impacting both parameters. This study developed a numerical model of crossflow PFHE and a two-dimensional flow distribution model under the condition of flow maldistribution. Experimental validation shows a standard deviation of 6.9%. This investigation delves into the effects of flow distribution offset (ξ) and non-uniformity (ε) on heat transfer performance and outlet temperature distribution. With large temperature differences, variations in fluid properties due to temperature lead to changes in the surface heat transfer coefficient (SHTC). The combined effects of SHTC and temperature difference determine the heat transfer performance. The results indicate optimal heat transfer performance and outlet cross-sectional temperature distribution at ξ= − 0.67 and 1, respectively. For a given ξ, increased non-uniformity deteriorates heat transfer efficiency and outlet cross-sectional temperature distribution. At ε=0.66, relative to the uniform flow, the heat transfer performance and standard deviation of outlet temperature distribution decrease by 10.3% and 45.1%, respectively.