Pool Boiling Heat Transfer on Directly 3D-Printed Metallic Micropillars on Silicon Chips
Year: 2025
Type: conference-paper
Abstract: This study investigates pool boiling heat transfer on metallic micropillar arrays fabricated directly onto silicon wafers using laser powder bed fusion (LPBF). A two-step deposition strategy was employed, in which a thin Sn-3Ag interlayer was printed to enhance metallurgical bonding and thermal compatibility, followed by the fabrication of AISi10Mg micropillars. The working fluid was TMC-49, tested at atmospheric pressure on both a bare silicon wafer and the LPBF-fabricated micropillar surface. High-speed imaging revealed that the bare silicon exhibited sparse nucleation at low heat fluxes, rapid bubble coalescence, and early vapor blanketing near CHF$(\sim 85\text{kW}/\mathrm{m}^{2})$, whereas the micropillar surface maintained uniform nucleation, rapid bubble departure, and continuous liquid rewetting up to CHF (−379$\text{kW}/\mathrm{m}^{2})$. This represents a$4.5\times$enhancement in CHF. The micropillar surface also exhibited$\mathrm{a} > 7\times$improvement in peak heat transfer coefficient (HTC), reaching$\sim 11.9 \text{kW}/\mathrm{m}^{2}\mathrm{K}$compared to$\sim 1.6\text{kW}/\mathrm{m}^{2}\kappa$for the plain wafer. These gains are attributed to increased nucleation site density, capillary-driven liquid replenishment through inter-pillar channels, increased stability in vapor venting, and additional surface roughness from LPBF-sintered particles that augment surface area and promote microlayer evaporation. The results demonstrate that LPBF offers a scalable alternative to traditional microfabrication methods, enabling high-performance boiling surfaces without complex cleanroom processing.
Institutions: Politecnico di Milano, University of Pisa, University of Twente
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W4415821980