Experimental study of boiling incipience in vertical narrow rectangular channel

To identify the discrepancy between different boiling incipience judgment criteria, a series of experiments on the boiling incipience are performed for water flow in a range of water mass flux varying from 100 to 1500 kg/(m2 s), heat flux from 20 to 200 kW/m2, inlet subcooling from 20 to 74 °C, and the pressure from 0.2 to 2 MPa. A parametric study has been conducted to investigate the effect of pressure, inlet subcooling, heat flux and mass flux. The entire experimental data obtained through different determination methods indicate that inception wall superheat is dependent on the inlet subcooling, heat flux and mass flux, but the variation of pressure does not lead to a significant change in boiling incipience. In addition, the comparison between experimental data gained from the different judgment criteria and boiling inception correlations does not present evident discrepancy, and the wall superheat at the location of boiling incipience in the present narrow rectangular channel has good agreement with the Thom correlation.