Numerical simulation and experimental characterization of ZrB 2 -HfB 2 ceramic composite for microchannel heat exchanger applications

Abstract

This study investigates the potential of advanced ceramics, specifically ZrB₂-HfB₂ reinforced with silicon carbide and carbon fibers (ZHSC_f), as alternatives to metals in microchannel heat exchangers. This research leverages the synergistic combination of ZrB₂, HfB₂, SiC, and C_f to enhance thermal performance, overcoming the limitations of monolithic ceramics. The primary objective is to evaluate the thermal efficiency of ZrB₂-HfB₂-SiC-C_f composite and compare their performance with Al₂O₃ and TiB₂-SiC for microchannel heat exchanger applications. The (ZrB₂-HfB₂-SiC-C_f) composite was fabricated using spark plasma sintering and comprehensively characterized for its phase composition, microstructure, and thermal properties. A computational analysis employing the finite element method (Ansys 2024 R1) was conducted to evaluate the thermal performance of the ZrB₂-HfB₂-SiC-C_f microchannel heat exchanger, comparing results against those of Al₂O₃ and TiB₂-SiC. The findings reveal that at a mass flow rate of 20.4 kg/h, ZrB₂-HfB₂-SiC-C_f offers a 52% increase in heat transfer over Al₂O₃ and 26% over TiB₂-SiC, similarly for the same mass flow rate the effectiveness of ZHSC_f increases by 46% over Al₂O3 and 26% over TiB₂-SiC. Combining high thermal conductivity and uniform microstructure ensures efficient heat dissipation and reduces thermal resistance, making ZrB₂-HfB₂-SiC-C_f composite a highly effective material for microchannel heat exchanger applications.