Thermohydraulic optimization of triple concentric-tube heat exchanger: A multi-objective approach

Abstract

In the present study, optimization of heat transfer and pressure drop characteristics in a triple concentric tube heat exchanger has been done using the results of numerical simulation. A commercial CFD software ANSYS Fluent v17.0 has been employed for simulating the flow and heat transfer, while optimization has been done by Response surface methodology (RSM) and Genetic algorithm (GA). The effective parameters in the study are Reynolds number (2500 ≤ Re ≤ 10,000) and Length to hydraulic diameter ratio (100 ≤ L/Dh ≤ 220). The optimum values, as well as the functional relationship between the design factors (Re and L/Dh) and response variables (Nu and f), have also been developed. It has been found that both the design factors (Re and L/Dh) have a strong influence on the response variables (Nu and f). With the increase in Re (flow rate), a large growth in Nusselt number and decline in friction factor has been observed. However, with the increase in L/Dh, an enormous decrease in both Nusselt number and friction factor has been found.