高热流条件下过冷沸腾流动阻力特性试验研究

过冷沸腾在高热流冷却场合得到了广泛的应用，如聚变堆偏滤器冷却、压水堆堆芯冷却。其中，过冷沸腾流动阻力是换热系统设计的关键内容之一。试验研究了高热流条件下竖直通道内水的过冷沸腾流动阻力特性，试验段为内径6 mm、长径比44.4的不锈钢圆管。试验参数范围：热通量7.5~12.5 MW/m²，质量流速6000~10000 kg/(m²?s），系统压力3~5 MPa，进口流体温度80~200℃。分析了质量流速、热通量、压力、沸腾数、Jacob数等参数对阻力的影响。结果显示，过冷沸腾流动阻力随着热流及质量流速的增加而增加，随压力增加而减小。将试验数据与文献中的经验关联式作对比，结果表明各关联式的预测误差较大，主要归结于拟合参数及工作流体的差异。研究发现管径尺寸效应也是影响阻力的一个因素，为此在前期成果的基础上，提出了一个添加管径因素修正项的经验关联式，该关联式的预测误差在±18%范围内。

Experimental study on pressure drop for subcooled water flow boiling under high heat fluxes

Subcooled boiling has been widely used in high heat flow cooling applications, such as fusion reactor divertor cooling and pressurized water reactor core cooling. In this paper, the pressure drop characteristics of subcooled water flowing in a vertical stainless circular tube are experimentally investigated under high heat fluxes condition. The test tube has an inner diameter of 6 mm and a length-to-diameter of 44.4. The operating parameters are as follows: heat flux q = 7.5—12.5 MW/m², mass flux G = 6000—10000 kg/(m²?s), pressure p = 3—5 MPa, and inlet fluid temperature T _b = 80—200℃. The effects of mass flux, heat flux, pressure, boiling number and Jacob number on subcooling boiling pressure drop were discussed. The results show that subcooled boiling pressure drop increases with increasing heat and mass fluxes but decreases with increasing pressure. The experimental data are compared with the available empirical correlations, and it is found that these correlations cannot well predict our data, which may be mainly due to the variations in operating parameters and working fluids. Moreover, it is observed that the subcooled boiling pressure drop is affected by diameter effect. Therefore, a new correlation is proposed based on our previous correlation, in which a correction term for diameter effect is added. The new correlation can capture the experimental data within ±18% error bands.