Heat transfer and pressure drop in the boiling two-phase flow between the parallel porous and heating walls

摘要

Experimental investigations were made on the boiling heat transfer enhancement in the flow boiling field by using a unique method, which was already proposed by the authors in the pool boiling case. In this method a porous sheet, i.e. a screen, was used. It was set parallel to the heating wall with a very small separation (small gap). When the nucleate boiling occurred on the wall, vapor bubbles were trapped by the screen in this gap. Then they moved along the heated surface, causing the heat transfer augmentation in the authors' previous experiment under the small heat flux conditions. Although the pressure drop was increased considerably, the results showed that this effect was also valid in the flow boiling case under larger heat flux conditions.