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.