Thermo-hydraulic performance evaluation through experiment and simulation of additive manufactured Gyroid-structured heat exchanger

Abstract

Following the breakthrough of additive manufacturing in overcoming machining limitations, triply periodic minimal surface (TPMS), governed by mathematical implicit functions, has emerged as a highly promising configuration for heat exchanger. Current study evaluates the thermo-hydraulic characteristics of a 316L stainless steel Gyroid-structured heat exchanger, manufactured by selective laser melting (SLM), through experimental and numerical methods. The experiment was conducted on a single-phase test rig with water as the working medium. The measured performance is affected by surface roughness and other factors, resulting in deviations from the theoretical performance. Specifically, at a flow rate of 500 kg/h, the experimentally measured overall heat transfer coefficient and cold-side differential pressure exhibit a 9.70 % and 69.82 % increase, respectively, compared to their theoretical values. In comparison to various heat exchangers reported in the literatures, this experimental model possesses a notable advantage concerning the power density achievable per unit length of pressure drop consumed. In addition, a nonlinear regression method based on the least squares approach and the thermal resistance separation method is proposed to obtain the Nu ∼ Re correlation. The fitting effect is satisfactory, as all the points fall within the deviation range of (-7.5 %, 7.5 %). Moreover, this experimental model outperforms four conventional heat exchanger configurations in terms of performance evaluation criteria.