Exploring the onset of nucleate boiling with hypervapotron channel for tokamak cooling system application

Abstract

In present paper, onset of nucleate boiling (ONB) of one-side heated hypervapotron (HV) channel was studied. Through sub-cooled flow boiling experiments under the conditions of a pressure of 1–10 bar, a mass flow rate of 0.071–0.284 kg/s, an inelt fluid temperature of 40–140 °C, and a heat flux of up to 10765 kW/m2, ONB heat flux was experimentally explored. As a result, the HV channel recorded an average 186.91% improvement in ONB heat flux compared to the flat channel due to the vortex secondary flow induced by the fin structure arrangement. In addition, the effect of the system parameters on the ONB heat flux of the HV channel was analyzed. In addition, it was evaluated how well the existing ONB correlations predict the ONB of the HV channel under one-side high heat load conditions. Unfortunately, they tend to under-predict the enhanced ONB of the HV channel because they are correlations developed for the circular smooth channel. Therefore, the authors of this study developed a new correlation using a Python code grafted with machine learning technology.