Numerical analysis and correlation of thermohydraulic characteristics of louvered fin-tube heat exchanger

Abstract

Louvered fins are compact heat exchangers that have a high heat-transfer area compared to their volume. The interrupted surface of a louvered fin improves heat transfer by repeating the disruption and regeneration of the boundary layer generated by the flow. The current study presents the empirical correlations between the heat and friction coefficient according to geometric parameters using a numerical approach. The proposed empirical correlations that include the flow depth are more accurate than those that do not contain the flow depth. Additionally, this study presents the process of developing a numerical simulation. The simulated and experimental results were compared, and both the friction f factor and Colburn j factor exhibited high accuracy, with errors within ±9%. The verified simulation produced heat transfer and friction results for each heat-exchanger geometry. Empirical correlations were developed based on the data obtained from the simulation, and 91% and 87% of the f and j factors exhibited error within ±10% with the simulation data, respectively. This enabled the development of empirical correlations for thermohydraulic characteristics that can be applied to the design of a compact heat exchanger with louvered fins, and suggestions for the optimal design of each parameter were presented.