Air-side thermal-hydraulic analysis and parameter optimization for vertical-fin microchannel heat exchanger

Abstract

The vertical-fin microchannel heat exchanger (VMHX) has efficient thermal-hydraulic performance and favorable drainage performance, which is capable to be utilized in the air source heat pump under wide operating conditions. In this article, CFD is employed to analyze the air-side thermal-hydraulic performance of VMHXs under dry conditions. The model is verified by experimental results with an error of less than 20%. Then, the sequence and connection of wave and louver on composite fins are compared, while the effects of fin pitch, fin length, tube pitch, and fin thickness are investigated. Finally, parameter optimization is conducted by Taguchi method. Results show that under the same pump power, the heat transfer enhancement of the fin with front louver and rear wave connected reversely is the best. When the comprehensive index performance evaluation criteria (PEC) is used as performance evaluation of VMHXs, the tube pitch and fin length are the main factors. Within the range of parameters practically available, the best performance is obtained by the combination of 1.8 mm fin pitch, 25.6 mm fin length, 12.0 mm flat tube pitch, and 0.12 mm fin thickness.