Heat Transfer and Fluid Flow Characteristics in a Heat Exchanger Tube Fitted With Inserts

Abstract

The aim of this study is to simulate and analyze the heat transfer and fluid flow characteristics for a tube of a heat exchanger fitted with inserts. The purpose of these inserts is to increase the heat transfer rate and improve the thermal performance of the heat exchanger. In this study, several types of tube inserts are simulated via a commercial computational fluid dynamics (CFD) solver. These insert types are presented as a single tube fitted with twisted tapes (TTs), twisted tapes with rod (TTR), and helical twisted tapes (HTT) with rod. To assess the performance of each insert type, the CFD results are presented in dimensionless form such as the Nusselt number (Nu), friction factor (f), and performance evaluation criteria (PEC). Additionally, useful dimensionless correlations are developed and presented in this paper to predict the performance of the heat exchanger over a wide range of Reynolds number and tape twist ratio. To ensure accurate CFD results, grid independence test and model validation study against previously reported experimental data were performed.