Thermal and hydrodynamic analysis of a compact heat exchanger produced by additive manufacturing

The demand for higher heat transfer effectiveness has stimulated the combination of compact heat exchangers and additive manufacturing. The potential to fabricate complex geometries with different materials can optimize the trade-off between heat transfer and pressure drop. In this work, theoretical models for thermal and hydrodynamic performance were developed for a cross-flow compact heat exchanger manufactured with the SLM process, an alternative to Printed Circuits Heat Exchangers. The heat exchanger core has a cubic format with 100 mm edge and 2 mm channel diameter. The raw material used is AISI 316L stainless steel. Furthermore, the relative density of the prototype is 99.8% and the surface roughness measured was 12.21 µm. The one-dimensional steady-state with circular mini channels models are validated with experimental data. The experiments were evaluated in laminar, transition, and turbulent regimes, with different temperatures. The theoretical models have a good agreement, with 3.3% and 15.3% average errors for the thermal and hydrodynamic models. Besides, the impact of surface roughness in the pressure drop was negligible. The influence of replacing the core material in the thermal performance is significant in the turbulent regime.