INVESTIGATION ON SUPERCRITICAL FLUIDS HEAT TRANSFER DETERIORATION AND ITS MITIGATIONS

2018 ◽  
Author(s):  
Eze Chika ◽  
Hui Cheng ◽  
Jiyun Zhao
Keyword(s):  
Heat Transfer ◽  
Supercritical Fluids ◽  
Heat Transfer Deterioration

A New Analysis of Heat Transfer Deterioration on Basis of Turbulent Viscosity Variations of Supercritical Fluids

2012 ◽  
Vol 134 (12) ◽  
Author(s):  
Mahdi Mohseni ◽  
Majid Bazargan
Keyword(s):  
Heat Transfer ◽  
Turbulent Flows ◽  
Supercritical Fluids ◽  
Turbulent Viscosity ◽  
Convection Heat Transfer ◽  
Two Dimensional ◽  
Convection Heat ◽  
Heat Transfer Deterioration ◽  
Computational Fluid Dynamics Cfd ◽  
Flow Turbulence

A two-dimensional computational fluid dynamics (CFD) code has been used to study the anomalies encountered in convection heat transfer to upward turbulent flows of supercritical fluids in tubes. In this study, the effect of turbulent viscosity variations on heat transfer deterioration (HTD) and the mechanisms involved have been investigated. The results show that the suppression of the flow turbulence which leads to the deterioration of heat transfer can be partially due to the decrease in the turbulent viscosity as a result of density decrease along a heated flow. Before this study the buoyancy and the thermal acceleration effects were called as the main two known mechanisms for the heat transfer deterioration.

Numerical Analysis of Supercritical Water Heat Transfer in Horizontal Circular Tube

2009 ◽  
Author(s):  
Bo Zhang ◽  
Jianqiang Shan ◽  
Jing Jiang
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Supercritical Fluids ◽  
Supercritical Water ◽  
Circular Tube ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Heat Transfer Deterioration ◽  
Horizontal Flows ◽  
Safety And Reliability

CANDU supercritical water reactor (SCWR) offers advantages in the areas of sustainability, economics, safety and reliability and proliferation resistance. However, there is still a big deficiency in understanding and prediction of heat transfer behaviour in supercritical fluids. In this paper, heat transfer is numerically investigated on supercritical water for three-dimensional horizontal flows. Three ε-type turbulence models are tested and the numerical results are compared with experimental data. Based on the result, the standard k-ε turbulence model with enhanced wall treatment is recommended. The effect of the buoyancy and heat transfer deterioration is also analyzed, and the criteria for onset of buoyancy effects is evaluated. The quantity Gr/Re2.7 recommended by Jackson et al. (1975) gives a capacity to predict the buoyancy.

Sign in / Sign up

Export Citation Format

Share Document