Distribution Characteristics and Structure Optimization of Printed Circuit Heat Exchangers

Abstract

Based on the structural characteristics of actual PCHEs, a primitive header model suitable for predicting and analyzing the flow distribution characteristics of gas‑liquid two‑phase flow inside PCHEs was established by taking the heat exchanger header and twelve microchannels as the modeling objects and using natural gas liquid‑vapor mixture as the working fluid. The model considers the interaction between gas and liquid phases and tracks the interfacial movement of gas‑liquid two‑phase flow based on the VOF method. Single‑phase flow studies were carried out with liquid methane and gaseous methane as working fluids respectively, and numerical simulations were performed on the primitive header model and hyperbolic header models with different curvatures under various inlet parameters. Meanwhile, an improved hyperbolic header structure was proposed. The geometric feature of the hyperbolic structure is that the cross‑sectional area changes continuously and smoothly along the flow direction. This design prevents eddies and dead zones caused by sudden cross‑section expansion during fluid diffusion, gradually homogenizes the fluid velocity field, and ensures smaller flow deviation into each microchannel. Furthermore, the smooth wall of the hyperbolic structure suppresses the generation of turbulent eddies, allowing the fluid to maintain a more stable laminar or transitional flow regime during expansion.