The effect of gap distance on the heat transfer between a heated finned surface and a saturated porous plate

Experiments were performed to investigate the effect that the presence of a gap has on the heat transfer between a heated finned surface and a saturated porous plate with an average pore radius of 200μm. There was evidence that the vapour generated beneath the heated surface can escape to the vapour grooves more easily when a gap distance is introduced. This seemed to decrease the vapour penetration into the porous plate. The heat transfer performance of the heated finned surface initially increased as the gap distance was increased from 0 to 500μm, but remained relatively unchanged for gap distances of 500–900μm.