CHF correlation of boiling in FC-72 with micro-pin-fins for electronics cooling

An experimental study of pool boiling heat transfer was conducted for micro-pin-finned surfaces with different pitches (45, 60, and 75 μm) and configurations. The experimental conditions covered three different liquid subcoolings (15, 25, and 35 K), and dielectric liquid FC-72 was used as working fluid. The dimension of the silicon chips is 10 × 10 × 0.5 mm³ (length × width × thickness). For comparison, experiments on a smooth surface named chip S were also conducted. It is found that the fin pitch and configuration have significant effects on the boiling heat transfer coefficient as well as critical heat flux. Considering the surface area enhancement ratio (A_PF/A_S), dimensionless number representing flow resistance (D_h/L_c, named capillary-resistance number), porosity (φ) and liquid subcooling (ΔT_sub), a correlation to predict CHF for different micro-pin-finned surfaces was proposed. The prediction results agree quite well with the experimental data within ±8%.