Parametric optimization of heat exchangers, validation by 3D printing

The advancement in metal additive manufacturing has tremendously increased the optimization and design possibilities of heat exchangers systems. In this work, we present possible design improvements and an advanced extended surfaces optimization for plate and fins heat exchangers. An experimental assessment was conducted on 3D printed mini channels to evaluate their thermal hydraulic properties with respect to the one manufactured conventionally. The 3D printed channels shows good agreements with the correlations already found in the literature in the laminar flow regime. The validated correlations were used to conduct the design and parametrical optimization of a wavy fin heat exchanger. The heat exchanger obtained from the design process optimized for the 3D printing was 50% lighter than the one usually used by conventional manufacturing for the same heat duty and pressure drop. Furthermore, an advanced parametrical optimization was applied by changing the local amplitude of each fin wave along the flow. This permitted to reduce the operating cost by 15% for the same heat exchange rate. A local enhancement by material removal was conducted on an offset fin heat exchanger using the commercial computational fluid dynamics FLUENT. By removing 12% of thermally ineffective cells, the pressure drop was reduced by 20% for the same heat duty. A new generation of offset fins is proposed which reduced the heat exchanger volume by 50% maintaining its same overall thermal hydraulic performance.