Numerical Analysis of Generation of Colburn-j Factor for the Plain Rectangular Fins of a Compact Heat Exchanger Using CFD Approach

Abstract

A Compact Heat Exchanger is characterized by a high heat transfer area per unit volume, which can be achieved by using very high-density fins. A plain fin is one of the most commonly used fins as it has advantages such as low-pressure drop and it is easy to fabricate several types of fins by changing its geometric parameters such as fin height (h), fin spacing (s), and fin thickness (t). In this study, a numerical investigation is carried out on a plain rectangular fin to establish a correlation for the Colburn-j factor. The analysis is done for a wide range of Reynolds (Re) numbers covering both the laminar region (400 ≤ Re ≤ 2500) and turbulent region (3500 ≤ Re ≤ 12000). A CFD-based numerical study is performed using ANSYS Fluent 21 with air at 300 K as the working fluid. In this numerical analysis, the Colburn-j factor data is obtained for different Reynolds numbers as well as for the different non-dimensional geometrical parameters such as the fin height, fin spacing, and fin thickness values. This data has been validated with experimental data available in the open literature. The correlations of the Colburn-j factor are established for a wide range of Reynolds numbers along with the geometric parameters of the plain fins covering the entire operational range of the Compact Heat Exchangers for Aerospace as well as for other applications.