Numerical investigation of the effect of chevron angle on thermofluids characteristics of non-mixed and mixed brazed plate heat exchangers with experimental validation

Abstract

Effect of chevron angle on thermofluids characteristics of Brazed Plate Heat Exchangers (BPHEs) are studied experimentally and numerically. The simulations include the effects of brazing joints and inlet/outlet port distribution that were normally overlooked in the existing literature. Four types of non-mixed BPHEs are considered with various chevron angles: L (35°), M (50°), H (65°), and LH (35°/65°). These four types of non-mixed BPHEs are combined in order to produce four types of mixed BPHEs: L+M, M+H, L+H, and LH+H. Results show that rise of chevron angle leads to the augmentation of Nusselt number and friction factor. Hence, type H and type L have the maximum and the minimum Nusselt numbers and friction factors among all non-mixed and mixed BPHEs. However, type H has the worst performance based on volume goodness factor method, while type M has the best performance among all modeled BPHEs followed by type L+M. Detailed flow study illustrates that rise of chevron angle leads to change in flow pattern from chevron angle direction to zig-zag or straight direction, which causes increase in heat transfer rate and pressure drop. Correlations are developed for Nusselt number and friction factor of non-mixed and mixed BPHEs in a wide range of Reynolds number between 50 and 10,000 with mean deviations of 9%.