Heat Transfer in Nucleate Boiling within a Vertical Narrow Space

Pool boiling heat transfer within a confined space was studied for the vertical narrow space between parallel heated and unheated planes. Experiments were performed for water under atmospheric pressure at a heat flux range up to the critical heat flux. The gap size was decreased from 5 mm to 0.15 mm in four steps and two heating surfaces of different heights were tested under the open or closed periphery condition of the narrow space. Based on observed boiling behavior, heat transfer mechanisms were deduced and the heat fluxes calculated by proposed models were compared with experimental data.