プール沸騰に関する研究 : 第7報, マクロ液膜厚さの相関式の修正と低熱流束域でのマクロ液膜厚さの測定

抄録

Macrolayer thickness at critical heat flux was measured for various liquids in the pressure range of 0.05MPa to 0.35MPa for upward and vertical disk heaters of 20mm diameter. Macrolayer thickness is determined based on the energy balance relation q_CHF=ρ_lH_fgδ_l·f, with measurements of the critical heat flux and the detachment frequency of vapor masses (coalesced bubbles) completely covering the heating surface. The correlation of macrolayer thickness proposed in the 4th report of this series by Kumada and Sakashita [Trans. JSME, 58-552 (1992), 2505] was modified with the data obtained in the present report. Macrolayer thickness in low heat fluxes for water and ethanol under atmospheric pressure was also measured by changing the orientation of the heating surface from a vertical direction to a downward direction. The data in low heat fluxes were thinner than the existing data measured by a probe method in the nucleate boiling region and agreed fairly well with the proposed correlation.