Heat transfer deterioration of aviation kerosene flowing in mini tubes at supercritical pressures

Heat transfer performances of aviation kerosene flowing in mini tubes at supercritical pressures were investigated experimentally and numerically. A ten-species surrogate model with the extended corresponding state was used to calculate the thermophysical and transport properties of kerosene and the Re-Normalization Group (RNG) k-ε turbulent model with the enhanced wall treatment was adopted to consider the turbulent effect. The numerical results agree well with the experimental data. Two types of heat transfer deterioration were observed in this paper. The first type of deterioration occurs at the place where the wall temperature exceeds the pseudo-critical temperature, while the second type occurs when the bulk fluid temperature exceeds the pseudo-critical temperature. The effects of several key parameters, such as mass flow rate, heat flux, pressure and inlet temperature on heat transfer deterioration were studied in detail. The results reveal that the heat transfer coefficient increases with increasing mass flow rate and inlet temperature. The effect of heat flux on heat transfer is complicated, while the effect of pressure on heat transfer is insignificant. Heat transfer deterioration can be effectively eliminated by increasing mass flow rate and pressure and decreasing heat flux and inlet temperature. The dramatic variation of thermo-physical properties is the main reason for the heat transfer deterioration.