Effects of pass arrangement and optimization of design parameters on the thermal performance of a multi-pass heat exchanger

This paper presents a numerical evaluation of the flow distribution and thermal performance of a multi-pass, multi-channel heat exchanger as functions of the number of passes and inlet diameter. To determine the optimal number of passes for a fixed size of heat exchanger, we investigated the JF factor by varying the number of passes and the inlet diameter. We determined the optimal number of passes for a given inlet diameter by studying the variation of the JF factor as a function of the ratio of the inlet diameter to header height ratio. For instance, the optimal number of passes was two for an inlet diameter of 50 mm, and the performance based on the JF factor was improved by about 89% compared to a reference heat exchanger. We further optimized other design parameters, such as the inlet location, separator location, and header width to improve the heat exchanger performance by an additional 20%.