Experimental Investigation on Heat Transfer of Kerosene Flowing in a Vertical Tube at Supercritical Pressure

The flow and heat transfer characteristics of kerosene flowing in a vertical upward circular tube were experimentally investigated. The tube is 1 mm in diameter and 300 mm in length. Pressure ranges from 2.5~4 MPa, mass flow rate ranges from 0.7~1.7 g/s, and heat flux ranges from 0.06 ~ 1 MW/m². Analysis was done to find out how the heat transfer coefficient changes with the local fluid temperature. Influence of different experimental parameters on heat transfer was also concluded. Results indicate that heat transfer of kerosene under supercritical pressure is mainly determined by its physical properties and the flow state. The heat transfer characteristics of kerosene under supercritical pressures could be divided into three regimes, namely the common heat transfer regime, the enhanced heat transfer regime and the deteriorated heat transfer regime. Heat transfer enhancement is due to the combination of turbulent mixing and the drastic change of properties of kerosene near pseudo-critical temperature in the near wall zone while heat transfer deterioration is caused by the "pseudo-film boling" of the high temperature fluid in the near wall region.