Heat transfer to aviation kerosene flowing upward in smooth tubes at supercritical pressures

This study experimentally investigated convective heat transfer performances of China RP-3 kerosene flowing in a vertical upward tube under supercritical pressures. Effects of mass flux, heat flux, pressure and inlet temperature on the heat transfer performance were given in detail. The influences of buoyancy and flow acceleration under different flow conditions were discussed as well. It was found that the inner wall temperature varies non-linearly at different mass fluxes. Heat transfer is improved when the fuel temperature is around the critical temperature. The heat transfer coefficient increases as heat flux or inlet temperature increases, while increase in inlet pressure reduces heat transfer coefficient. Besides, as nanofluids generally have higher thermal conductivity compared to their corresponding base fluids (i.e. kerosene), the heat transfer characteristics of Fe3O4-kerosene nanofluid was also investigated. It was found that the addition of nanoparticles tends to deteriorate the heat transfer performance of nanofluids flowing in a vertical tube under supercritical pressure. As the particle content increases, the heat transfer coefficient decreases due to the modification of the inner wall surface by the nanoparticles. (C) 2015 Elsevier Ltd. All rights reserved.