TY  - EJOU
AU  - Wang, Shuo 
AU  - Wang, Huiming 
AU  - Zhang, Ying 
AU  - Zhang, Zhiqiang 
AU  - Jia, Li 

TI  - Experimental Study on the Flow Boiling of R134a in Sintered Porous Microchannels
T2  - Frontiers in Heat and Mass Transfer

PY  - 2025
VL  - 23
IS  - 6
SN  - 2151-8629

AB  - This experimental investigation was conducted on the flow boiling performance of refrigerant R134a in two types of parallel microchannels: sintered porous microchannels (PP-MCs) and smooth parallel microchannels (SP-MCs). The tests were performed under controlled conditions including an inlet subcooling of 5 ± 0.2°C, saturation temperature of 33°C, mass fluxes of 346 and 485 kg/m<sup>2</sup>·s, and a range of heat fluxes. Key findings reveal that the sintered porous microstructure significantly enhances bubble nucleation, reducing the wall superheat required for the onset of nucleate boiling (ONB) to only 0.13°C compared to 2.2°C in smooth channels. The porous structure also improves heat transfer coefficients at low and medium heat fluxes (&lt;20–30 W/cm<sup>2</sup>) and low vapor quality (x &lt; 0.2–0.4) due to augmented thin-film evaporation and intensified nucleate boiling. However, smooth microchannels exhibit superior performance under high heat flux and high vapor quality conditions, as the porous structure is prone to early dry-out and flow blockage. Notably, the porous microchannels demonstrate lower flow resistance and enhanced stability, with pressure drop fluctuations reduced by up to 46.4% in amplitude and 44.8% in standard deviation, attributed to improved capillary-assisted liquid replenishment and suppressed flow oscillations. The results underscore the potential of PP-MCs as a high-performance cooling solution for high-heat-flux applications.
KW  - Flow boiling; porous microchannels; heat transfer; pressure drop; flow instability; R134a; sintered surface

DO  - 10.32604/fhmt.2025.073226