Turbulent Heat Transfer to Heavy Liquid Metals in Circular Tubes

Volume 4 ◽  
2004 ◽  
Author(s):  
X. Cheng ◽  
A. Batta ◽  
H. Y. Chen ◽  
N. I. Tak
Keyword(s):  
Heat Transfer ◽  
Prandtl Number ◽  
Liquid Metals ◽  
Turbulence Models ◽  
Numerical Results ◽  
Heavy Liquid ◽  
Turbulent Heat Transfer ◽  
Turbulent Heat ◽  
Turbulent Prandtl Number ◽  
Mesh Structure

The present paper gives a brief literature review on turbulent heat transfer in heavy liquid metals (HLM), especially liquid lead-bismuth eutectic (LBE). Some models available in the open literature on heat transfer and turbulent Prandtl number are assessed. In addition, CFD analysis is carried out for circular tube geometries. The effect of turbulence models, mesh structure and turbulent Prandtl number on the numerical results is studied. Application of ε-type turbulence models with scalable wall function shows less dependence of the numerical results on mesh structure than the ω-type turbulence models with automatic wall treatment. The turbulent Prandtl number affects strongly the heat transfer performance. Comparison between the CFD results, heat transfer correlations and heat transfer test data reveals a decrease in turbulent Prandtl number by increasing Reynolds number. Based on the results achieved, recommendations are made on correlations of heat transfer and turbulent Prandtl number for LBE flows.

scholarly journals A Logarithmic Turbulent Heat Transfer Model in Applications with Liquid Metals for PR = 0.01-0.025

2020 ◽  
Author(s):  
Roberto Da Vià ◽  
Sandro Manservisi ◽  
Valentina Giovacchini
Keyword(s):  
Heat Transfer ◽  
Turbulence Model ◽  
Liquid Metals ◽  
Turbulence Models ◽  
Turbulent Heat Flux ◽  
Turbulent Heat Transfer ◽  
Transfer Model ◽  
Turbulent Heat ◽  
Reynolds Analogy ◽  
Wide Range

The study of turbulent heat transfer in liquid metal flows has gained interest because of applications in several industrial fields. The common assumption of similarity between the dynamical and thermal turbulence, namely the Reynolds analogy, has been proven to be not valid for these fluids. Many methods have been proposed in order to overcome the difficulties encountered in a proper definition of the turbulent heat flux, such as global or local correlations for the turbulent Prandtl number or four parameter turbulence models. In this work we assess a four parameter logarithmic turbulence model for liquid metals based on RANS approach. Several simulation results considering fluids with Pr = 0.01 and Pr = 0.025 are reported in order to show the validity of this approach. The Kays turbulence model is also assessed and compared with integral heat transfer correlations for a wide range of Peclet numbers.

scholarly journals Nusselt number correlation for turbulent heat transfer of helium–xenon gas mixtures

2021 ◽  
Vol 32 (11) ◽  
Author(s):  
Biao Zhou ◽  
Yu Ji ◽  
Jun Sun ◽  
Yu-Liang Sun
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Prandtl Number ◽  
Liquid Metals ◽  
Turbulent Heat Transfer ◽  
Working Fluid ◽  
Turbulent Heat ◽  
Heat Transfer Correlation ◽  
Heat Transfer Correlations ◽  
Prandtl Numbers

AbstractA gas-cooled nuclear reactor combined with a Brayton cycle shows promise as a technology for high-power space nuclear power systems. Generally, a helium–xenon gas mixture with a molecular weight of 14.5–40.0 g/mol is adopted as the working fluid to reduce the mass and volume of the turbomachinery. The Prandtl number for helium–xenon mixtures with this recommended mixing ratio may be as low as 0.2. As the convective heat transfer is closely related to the Prandtl number, different heat transfer correlations are often needed for fluids with various Prandtl numbers. Previous studies have established heat transfer correlations for fluids with medium–high Prandtl numbers (such as air and water) and extremely low-Prandtl fluids (such as liquid metals); however, these correlations cannot be directly recommended for such helium–xenon mixtures without verification. This study initially assessed the applicability of existing Nusselt number correlations, finding that the selected correlations are unsuitable for helium–xenon mixtures. To establish a more general heat transfer correlation, a theoretical derivation was conducted using the turbulent boundary layer theory. Numerical simulations of turbulent heat transfer for helium–xenon mixtures were carried out using Ansys Fluent. Based on simulated results, the parameters in the derived heat transfer correlation are determined. It is found that calculations using the new correlation were in good agreement with the experimental data, verifying its applicability to the turbulent heat transfer for helium–xenon mixtures. The effect of variable gas properties on turbulent heat transfer was also analyzed, and a modified heat transfer correlation with the temperature ratio was established. Based on the working conditions adopted in this study, the numerical error of the property-variable heat transfer correlation was almost within 10%.

scholarly journals A Logarithmic Turbulent Heat Transfer Model in Applications with Liquid Metals for Pr = 0.01–0.025

2020 ◽  
Vol 10 (12) ◽  
pp. 4337
Author(s):  
Roberto Da Vià ◽  
Valentina Giovacchini ◽  
Sandro Manservisi
Keyword(s):  
Heat Transfer ◽  
Turbulence Model ◽  
Liquid Metals ◽  
Turbulence Models ◽  
Turbulent Heat Flux ◽  
Turbulent Heat Transfer ◽  
Transfer Model ◽  
Turbulent Heat ◽  
Reynolds Analogy ◽  
Wide Range

The study of turbulent heat transfer in liquid metal flows has gained interest because of applications in several industrial fields. The common assumption of similarity between the dynamical and thermal turbulence, namely, the Reynolds analogy, has been proven to be invalid for these fluids. Many methods have been proposed in order to overcome the difficulties encountered in a proper definition of the turbulent heat flux, such as global or local correlations for the turbulent Prandtl number and four parameter turbulence models. In this work we assess a four parameter logarithmic turbulence model for liquid metals based on the Reynolds Averaged Navier-Stokes (RAN) approach. Several simulation results considering fluids with P r = 0.01 and P r = 0.025 are reported in order to show the validity of this approach. The Kays turbulence model is also assessed and compared with integral heat transfer correlations for a wide range of Peclet numbers.

Determination of Flow Characteristics and Turbulent Heat Transfer in a Ribbed Roughened Square Duct, Part 2: Numerical Simulations

2011 ◽  
Vol 110-116 ◽  
pp. 2364-2369
Author(s):  
Amin Etminan ◽  
H. Jafarizadeh ◽  
M. Moosavi ◽  
K. Akramian
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Flow Characteristics ◽  
Turbulence Models ◽  
Turbulent Heat Transfer ◽  
Turbulent Heat ◽  
Square Duct ◽  
Optimized Model ◽  
Rsm Model

In the part 1 of this research, some useful turbulence models presented. In that part advantages of those turbulence models has been gathered. In the next, numerical details and procedure of solution are presented in details. By use of different turbulence models, it has been found that Spallart-Allmaras predicted the lowest value of heat transfer coefficient; in contrast, RSM1 has projected the more considerable results compared with other models; besides, it has been proven that the two-equation models prominently taken lesser time than RSM model. Eventually, the RNG2 model has been introduced as the optimized model of this research; moreover.

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