The paper summarises the results of collaborative study involving the Universities of Pisa and Aberdeen in assessing the performance of some CFD codes and turbulence models in the simulation of heat transfer experiments with water at a pressure of 25 MPa in a heated circular pipe test section, covering a broad range of conditions of heat flux, mass flux and inlet temperature for upward and downward flow. Results, obtained using the SWIRL, FLUENT and STAR-CCM+ codes, showed that some models were effective in predicting heat transfer deterioration observed with upward flow for buoyancy-influenced conditions where the wall temperatures were below the pseudo- critical threshold. The effects of buoyancy in causing deteriorated heat transfer in upward flow and enhancing it in downward flow are clearly demonstrated. However, difficulties in predicting the heat transfer phenomena quantitatively were evident when the pseudo-critical temperature was reached within the boundary layer.
Assessment of Turbulence Models in the Simulation of Heat Transfer to Water at Supercritical Pressure in Upward and Downward Flow
AMBROSINI, WALTER;FORGIONE, NICOLA;
2010-01-01
Abstract
The paper summarises the results of collaborative study involving the Universities of Pisa and Aberdeen in assessing the performance of some CFD codes and turbulence models in the simulation of heat transfer experiments with water at a pressure of 25 MPa in a heated circular pipe test section, covering a broad range of conditions of heat flux, mass flux and inlet temperature for upward and downward flow. Results, obtained using the SWIRL, FLUENT and STAR-CCM+ codes, showed that some models were effective in predicting heat transfer deterioration observed with upward flow for buoyancy-influenced conditions where the wall temperatures were below the pseudo- critical threshold. The effects of buoyancy in causing deteriorated heat transfer in upward flow and enhancing it in downward flow are clearly demonstrated. However, difficulties in predicting the heat transfer phenomena quantitatively were evident when the pseudo-critical temperature was reached within the boundary layer.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
