Onset of Nucleate Boiling and Incipient Point of Net Vapor Generation in Narrow Channel

Abstract

Two-phase flow boiling in compact channel has attracted increasing interest in recent years.Because of it's small size, it can be used in small sized reactor or barge-mounted floating nuclear desalination plant. An important research content for the flow boiling in compact channel is to determine the onset of nucleate boiling (ONB) and incipient point of net vapor generation (IPNVG). An experimental study on ONB and IPNVG in narrow rectangular channel was presented. Flow direction in the channel was vertical upward. The experimental results indicate that the classical correlations of ONB for conventional channels were not suitable for the present narrow channel. The experimental results of IPNVG indicate that the heat flux, triggering net vapor generation in narrow rectangular channel, is litter lower than that calculated by correlations for conventional channels. A new correlation was developed to predict the ONB in narrow rectangular channel. The proposed correlation predictions agreed well with the experimental data.