Experimental study on onset of nucleate boiling in narrow rectangular channel under static and heaving conditions

An experimental study on onset of nucleate boiling (ONB) in narrow rectangular channel under static and heaving conditions was presented. Flow direction in the channel was vertical upward. The test runs were performed at atmosphere pressure. The mass flux ranged from 298 to 840 kg/m(2) s. The heat flux ranged from 33 to 184 kW/m(2). The inlet subcooling ranged from 28 to 55 K. The heaving motion was carried out by a six degrees-of-freedom platform. The heaving frequency ranged from 0.2 to 0.61 Hz. Under static conditions, the experimental results indicate that the heat flux and wall superheat, which were needed to initiate the nucleate boiling in narrow rectangular channel, increased with increasing mass flux and inlet subcooling. The classical correlations for conventional channels were not suitable for the present narrow rectangular channel. A new correlation was developed to predict the ONB in narrow rectangular channel under static conditions. The proposed correlation predictions agreed well with the experimental data. Under heaving motion, the fluctuation of mass flux was associated with heaving conditions. The heat flux and the wall superheat for ONB decreased with increasing heaving frequency. (C) 2011 Elsevier Ltd. All rights reserved.