A numerical investigation of the heat transfer deterioration (HTD) phenomena is performed using the low-Re k- turbulence model. Steady-state Reynolds-averaged Navier-Stokes equations are solved together with equations for the transport of enthalpy and turbulence. Equations are solved for the supercritical water flow at different pressures, using water properties from the standard IAPWS (International Association for the Properties of Water and Steam) tables. All cases are extensively validated against experimental data. The influence of buoyancy on the HTD is demonstrated for different mass flow rates in the heated pipes. Numerical results prove that the RANS low-Re turbulence modeling approach is fully capable of simulating the heat transfer in pipes with the water flow at supercritical pressures. A study of buoyancy influence shows that for the low-mass flow rates of coolant, the influence of buoyancy forces on the heat transfer in heated pipes is significant. For the high flow rates, buoyancy influence could be neglected and there are clearly other mechanisms causing the decrease in heat transfer at high coolant flow rates.
[1]
F. Dittus,et al.
Heat transfer in automobile radiators of the tubular type
,
1930
.
[2]
D. Wilcox.
Multiscale model for turbulent flows
,
1986
.
[3]
R. Duffey,et al.
Experimental study on heat transfer to supercritical water flowing in 1- and 4-m-long vertical tubes
,
2005
.
[4]
Donald M. McEligot,et al.
“Deterioration” criteria for convective heat transfer in gas flow through non-circular ducts
,
2004
.
[5]
S. Koshizuka,et al.
Numerical analysis of deterioration phenomena in heat transfer to supercritical water
,
1995
.
[6]
A. M. Shehata,et al.
Temperature, velocity and mean turbulence structure in strongly heated internal gas flows: Comparison of numerical predictions with data
,
2002
.