Enhancement of saturated flow boiling heat transfer on cylinders using interference sleeves

The perforated interference sleeve technique is employed to enhance saturated flow boiling heat transfer on cylinders. The technique gives larger enhancement factors at saturated flow conditions compared to subcooled flow conditions. High enhancement factors were encountered with large hole pitch sleeves but with the disadvantage of an early transition to film boiling conditions. This transition heat flux is not influenced by the liquid mass velocity. Sleeves with large gap clearance of 2.3 mm gave poor performance at 577 kg/m2s mass velocities. The best boiling curve with high enhancement factors and with high film transition fluxes at low heat flux levels, was obtained with the sleeves with 2 mm holes.