Experimental and numerical thermal-hydraulic performance analyses of a novel spiral printed circuit heat exchanger

Abstract

This study presents a comprehensive experimental and numerical investigation of a novel design Spiral Printed Circuit Heat Exchanger (SPCHE), evaluating its thermal-hydraulic performance against a conventional straight-channel Printed Circuit Heat Exchanger (PCHE). Water is used as a working fluid in both hot and cold channels. The finite element based framework is used to accurately capture the thermal-hydraulic behavior inside the SPCHE. Due to the channel curvature, Dean flow develops over the range of Reynolds numbers studied, motivating the use of a turbulent RANS 𝑘 – 𝜔 model. The numerical model is validated against experimental measurements to analyze various thermal hydraulics characteristics across Reynolds numbers ranging from 1000 to 12000 and hot-inlet temperatures from 323.15 K to 343.15 K. Results demonstrate that the spiral geometry induces secondary flows which significantly enhance thermal performance, yielding convective heat transfer coefficients exceeding 1 . 6 × 1 ⁢ 0 4 W m −2 K −1 and 2 . 0 × 1 ⁢ 0 4 W m −2 K −1 for the hot and cold channels, respectively at the expense of increased pressure drop. A comparative Performance Evaluation Criterion (PEC) analysis confirms a net thermal-hydraulic improvement of 52.5%–54.9% for the hot side and 35.4%–39.6% for the cold side. The heat duty is improved by 65%–70% with variation of the hot-inlet temperature from 323.15 K to 343.15 K. The experimentally validated friction factor and Nusselt number correlations with prediction errors within ± 5 % is obtained with current study. It provides a foundation for the enhanced performance design of advanced compact heat exchanger like SPCHE where high thermal efficiency and space constraints are critical. Furthermore, the spiral channels achieve a fourfold reduction in maximum dimension of the device corresponding to a linear compactness ratio ( 𝐿 s t r a i g h t / 𝐷 s p i r a l ) of 4.1, highlighting their superior space efficiency compared to straight channels.