Direct numerical simulation of supercritical flows in developing pipes
Turbulent heat transfer characteristics of supercritical pressure fluids are quite different from those of subcritical pressure fluids. Experimental studies showed that heat transfer to supercritical fluids can exhibit dramatic heat transfer deterioration or enhancement. These phenomena lead to the presence of local minima/maxima in heat transfer coefficients or wall temperatures along a heated surface. In nuclear reactors the prediction of wall temperature is of paramount importance to improve the safety and performance of the nuclear power plants. We perform Direct Numerical Simulation (DNS) of a heated pipe flow to study in detail the occurring mechanisms leading to the heat transfer deterioration. The simulation is such, that the temperature within the flow domain incorporates the thermodynamic region where large thermophysical property variations occur (figure1). Figure 2 shows an instantaneous enthaply distribution within a heated pipe flow simulation.