垂直管内超临界水传热实验研究

在宽广的实验范围内对直径10 mm垂直管内超临界水在不同工况下的传热特性进行了实验研究，分析了热流密度、质量流速及压力变化对内壁面温度及传热系数的影响规律。实验参数为：压力23、25、26 MPa，质量流速450~1 200 kg/（m²?s），热流密度200~1 200 kW/m²。实验结果表明：随主流温度的升高，壁面温度逐渐上升，在拟临界点附近由于物性剧变存在传热强化现象；热流密度的增加以及质量流速的减小均会削弱传热强化现象，并导致传热恶化；压力的影响主要体现在传热恶化、强化的起始热流密度和起始主流温度的不同。

Experimental Research on Heat Transfer Performance of Supercritical Water in Vertical Tube

Experimental research under supercritical pressure conditions was carried out on heat transfer performance in vertical tube of 10 mm with a wide range of experimental parameters. The impacts of heat flux, mass flow rate and pressure on wall temperature and heat transfer coefficient were investigated. The experimental parameters are following: The pressures are 23, 25, 26 MPa, the mass flow rate range is 450-1200 kg/（m²?s）, and the heat flux range is 200-1200 kW/m². Experimental results indicate that the wall temperature gradually increases with the bulk temperature, and heat transfer enhancement exists near the critical temperature as the drastic changes in physical properties. The increase in heat flux and the decrease in mass flow rate reduce heat transfer enhancement and lead to deterioration of heat transfer. The main effects of pressure are reflected in the difference of heat flux and bulk temperature of the start point where heat transfer deterioration and enhancement occur.