Experimental Investigation on Heat Transfer of N-heptane at Subcritical and Supercritical Pressures

Abstract

This paper has presented experimental results on heat transfer of n-heptane, the surrogate of kerosene, at subcritical and supercritical pressures. Results indicate that as for liquid heat transfer, slender boiling happens at the near wall zones when heat flux is high. When heat flux is low, both wall and bulk temperature increase. As for two-phase heat transfer, nucleate boiling happens at the anterior part of the tube. Heat transfer coefficient is extremely high. At the anterior part of the tube, film boiling happens, making heat transfer deteriorated. As for gas heat transfer, both wall and bulk temperatures increase, but heat transfer coefficient nearly keeps constant. Heat transfer under supercritical pressure is similar to liquid heat transfer at low heat flux. Both wall and bulk temperature increase along the tube, and heat transfer coefficient increases with bulk temperature.