Investigation of the flow boiling characteristic in mini channel with various micro pin fin

Flow boiling in mini-channel is a pivotal technique for airborne vapor compression cycles. This study conducts experimental tests to examine the flow boiling characteristics in mini-channel having four distinct pin fin configurations: diamond, square, circle, and sinusoidal. All channels maintain a uniform hydraulic diameter of 0.67 mm, with only a 2.3% variation in total heat transfer area. The experiments cover a range of operating conditions, including mass fluxes of 150 - 300 kg/(m²·s) and heat fluxes of 10 - 25 kW/m². The results reveal that the pin fin shapes have a significant impact on the pressure drop during flow boiling in mini-channel. Notably, the diamond fins exhibit the least flow resistance. In conditions of identical operation, the pressure drop in channels with square, circular, and sinusoidal fins increases by 303.6%, 120.0%, and 71.6% in meanly, respectively, compared to that of the diamond fins. However, the impact of fins on heat transfer property is less pronounced. Upon analyzing both the pressure drop and heat transfer property, the diamond fins emerge as the superior choice in terms of overall property. The insights gained from this research can inform future optimization efforts for airborne evaporator design.