Heat Transfer Augmentation of Compact Heat Exchangers Using Modern Innovative Techniques, A review and Parametric study

Abstract

This project presents a comprehensive review and numerical study on different ways of enhancing heat transfer rate and pressure loss reduction in compact heat exchangers (CHXs). The sole objective of this study is to gather major thermodynamic features of CHXs presented by researchers through both experimental and numerical investigation for innovative designing purpose of heat exchangers. The influence of fins and tubes spacing, geometry and shape on heat transfer performance is widely discussed. The effectuality of different fins types and their pattern, height, pitch/spacing on heat transfer augmentation and pressure drop reduction were considered. It is seen that convex louver fin yields better heat transfer performance than plane and louver fins. The influence of fin spacing on heat transfer performance varied with Reynolds number but their impact on pressure drop is negligible. The impact of elliptical and circular tubes with inline and staggered alignment on heat transfer enhancement and pressure loss is also widely discussed. Staggered alignment as compared to inline alignment of tubes in HXs leads to the higher heat transfer performance at the expense of larger pressure drop and also the optimal position for tubes is at downstream region instead of upstream region due to the significant enhancement of heat transfer performance because of horseshoe vortex formation. A numerical study was performed to acknowledge the influence of vortex generators on heat transfer augmentation and pressure drop reduction. The impact of VGs row numbers with different configuration is widely discussed. The effect of tubes arrangement i.e. inline and staggered on heat transfer performance and pressure drop of compact heat exchanger is also elucidated. It was found that CHXs with vortex generators yield better heat transfer rate as compare to compact heat exchanger without VGs. However, this arrangement yields higher pressure drop. Moreover, it was found that staggered tube arrangement tends to give higher heat transfer performance than inline arrangement of tubes.