Functional gradation of the morphological properties of TPMS channel for enhanced flow performance

Abstract

A triply periodic minimal surface (TPMS) is a functional cellular structure that is designed by defining the signed distance field (SDF) for periodically repeated unit cells. This study proposes a novel design methodology to functionally grade the morphology of a TPMS channel for enhancement of the fluid flow performance. Mathematical filtering was performed to change the SDF distribution through various combinations of multiple sigmoid functions, thus locally changing the TPMS geometry. The proposed local filtering was then implemented in the design of a TPMS flow channel to reduce the flow resistance in the inlet and outlet regions. Pressure drop tests were conducted using additively manufactured TPMS channels, and the results showed that the pressure drop decreased by 20% for the filtered design with a volume change of only 2.6%. Numerical simulations were performed to analyze the cause of reduced flow resistance in the locally filtered regions, and the results were verified through flow visualization experiments. Considering that a TPMS structure has a complex geometry and thus its manual modification is very difficult, the proposed filtering method offers an efficient approach for functionally changing the morphology of the TPMS structure.