超临界压力正癸烷在竖直圆管内的流动阻力实验

研究了加热条件下超临界压力下正癸烷在竖直细圆管内的流动阻力特性，分析了热流密度、系统压力以及进口温度对摩擦压降的影响规律。实验结果表明:当流体温度较低时，流体摩擦压降随着热流密度的升高而逐渐降低；当流体温度逐渐接近拟临界温度时，由于物性的剧烈变化，流体摩擦阻力压降随着热流密度的升高而增加。并且系统压力越低，拟临界点附近的变化就越剧烈。当流体温度高于拟临界温度时，物性变化趋于平稳，流体摩擦压降随热流密度升高而增加。基于实验结果，总结出了一种针对不同温度、不同热流密度与质量流速比值范围的摩擦阻力系数经验关系式。 

Experiment on flow resistance of n-decane invertical tube at supercritical pressure

The flow resistance characteristics under heating condition of n-decane in the vertical miniature tube at supercritical pressure were investigated. The influence of heat flux, system pressure and inlet temperature was mainly studied. The result indicated that, the pressure drop due to frictional resistance in tube decreased with the rise of heat flux when fluid temperature was not very high. When temperature rose to the pseudocritical point, due to the effect of thermal physical properties, the pressure drop increased. And the lower system pressure led to more violent pressure drop changes. While the temperature of fluid was higher than the pseudo-critical temperature, pressure drop went up with increases of heat flux because of steady thermal physical properties. As a result, an empirical correlation of frictional resistance was derived for different temperatures and ratios of heat flux to mass velocity.