Experimental study on flow boiling heat transfer characteristics of porous pin-finned array structures

The instability of pressure and temperature in flow boiling could easily lead to earlier reaching of drying limit of microchannels. A comparative study on supercooled flow boiling heat transfer experiments for sintered pin-finned array structures was performed using deionized water as the working fluid. The pin-finned structure was sintered with 30 μm, 90 μm and 150 μm spherical copper powder, and the inlet water temperature was maintained at 60 ℃. The results show that particle size has a significant effect on heat transfer coefficient and critical heat flux qCHF of flow boiling in porous microchannels. The PF-150 sample showed the lowest wall superheat at high heat fluxes at a mass flux of 52 kg∙m-2∙s-1, and its qCHF reached 134 W∙cm-2. The visualization results show that the larger particle size samples presented lower pressure amplitude and more-ordered pressure fluctuation, which improves the boiling heat transfer performance of the pin-finned array. Increasing mass flux can move the wet-drought boundary backwards to ensure adequate liquid supply in the rear part, and greatly reduce the instability of flow boiling. The results indicate that the sintered pin-finned array has great potential in improving flow boiling performance. © 2024 Zhejiang University. All rights reserved.