Research on enhanced heat transfer mechanism between gas-liquid two phases inside scrubbing cooling tube with circular fins

Intensifying the gas-liquid two-phase heat exchange within scrubbing-cooling tubes is the critical research topic for industrial high-temperature syngas temperature reduction. This work investigates how externally mounted tube fins strengthen internal heat transfer, and systematically evaluates how fin count, thickness and height affect the tube's gas-liquid thermal performance. Additional analysis is carried out to clarify how the initial liquid film temperature modulates various in-tube turbulent heat transfer characteristic quantities.Numerical results demonstrate that external fins can substantially lower tube wall temperatures. Raising the fins quantity amplifies internal turbulent fluctuations and elevates all turbulent heat transfer indexes, with 29 fins identified as the optimal configuration. As fin thickness grows, two-phase turbulent parameters follow an upward-then-downward trend, fin efficiency rises monotonically alongside thickness, and the peak heat rejection capacity reaches roughly 547.53 W, with 5 mm selected as the best fin thickness. Moderately extending fin height improves internal heat exchange, yet overly long fins degrade heat dissipation performance. Fin efficiency drops continuously with growing fin height, while total heat dissipation rises first before declining, and the optimal fin height is determined as 10 mm.Moreover, the liquid film higher starting temperature pushes up wall temperature and cuts down the vapor volume fraction. Extreme gas-liquid temperature differences (either excessively large or small) suppress heat transfer augmentation, so the moderate temperature gap between the two phases is required to achieve favorable thermal performance.