Numerical study on heat transfer behavior of wavy channel supercritical CO2 printed circuit heat exchangers with different amplitude and wavelength parameters

Performance enhancement of printed circuit heat exchanger (PCHE) is of great importance to the thermal efficiency improvement of supercritical CO2 Brayton cycle. In this paper, the heat transfer performance and flow characteristics of a sinusoidal wavy channel PCHE are numerically investigated. The effects of the amplitude and wavelength parameters are discussed under different mass flow conditions with inlet Re -= 5210.8-13026.9 on the hot side. It's found that the increase of amplitude and decrease of wavelength result in larger flow length and heat transfer area of the wavy channel, as well as higher heat transfer rate. The use of wavy channel instead of straight channel enhances heat transfer. Because of the complicated flow fields in the wavy channels affected by thermophysical property changes and centrifugal forces, the shapes and locations of high heat flux zones shift with different configurations. The secondary flow and heat transfer area change both contribute to the change of heat transfer characteristics. The resulting complicated heat transfer performance variation of different configurations are illustrated and discussed. Based on the overall performance evaluation results, the best performance is obtained with an amplitude of 3 mm and a wavelength of 50 mm or 75 mm. (C) 2019 Elsevier Ltd. All rights reserved.