Numerical modeling of heat exchange and turbulent flow of fluid within tubes at supercritical pressure

Modes of normal and degraded (with peaks of wall temperature) heat transfer are computed for the turbulent flow of carbon dioxide within a circular tube at supercritical pressure. Computation is based on a set of motion, continuity, and energy equations written under the approximation of a narrow channel. The turbulence model uses the Prandtl formula for the turbulent viscosity. The relationship for the travel length takes into account the effect of variation in the fluid properties and thermal acceleration through the tube section. Computation results for variation in the wall temperature along the tube fit the experimental data. An explanation is given for causes of the appearance of the peak on the wall temperature distribution along the tube in the area, where the fluid temperature is close to the pseudocritical temperature.