Augmentation of boiling heat transfer by free particles bed (2nd report, experiments on a flat heating surface)

摘要

An experimental study was made of saturated nucleate pool boiling with particle beds, in which particles are freely movable in liquid. The particle beds are set on a horizontal, flat 30mm diameter copper heating surface. The heat transfer characteristics are measured. Materials used for particles are alumina, aluminium and glass and the diameter ranges from 0. 5nn to 2. 5mn. The maximum augmentation ratio obtained reaches about 7 tines of heat transfer coefficient in liquid. The mechanism of augmentation is discussed. This is a passive technique, though particles movement caused by bubble formation augments heat transfer like an active one.