Numerical Studies of Supercritical Turbulent Convective Heat Transfer of Cryogenic-Propellant Methane

In this paper, comprehensive numerical studies of the turbulent convective heat transfer of the cryogenic-propellant methane flowing inside a horizontal minitube under supercritical pressures have been conducted, based on a complete set of conservation equations and accurate evaluations of the thermophysical properties. The present numerical investigations focus on fundamental understanding of the effects of many key parameters, including the inlet pressure, wall heat flux, inlet velocity, and inlet temperature, on the supercritical heat transfer phenomena and the variations of the Nusselt number. Results indicate that drastic property variations at the pseudocritical temperature under a supercritical pressure would cause local heat transfer deterioration. Increasing the inlet methane pressure would result in improved heat transfer at supercritical pressures. particularly under a high wall heat flux, i.e., 7 MW/m(2). The conventional empirical expressions, i.e.. the Gnielinski equation, cannot be used for the supercritical heat transfer predictions of the cryogenic-propellant methane at supercritical pressures. A modified heat transfer expression. which is applicable to the supercritical cryogenic methane, has been successfully established in this paper.