Improving predictions of heat transfer in indoor environments with eddy viscosity turbulence models

The one-equation, eddy-viscosity transport model of Gulyaev, Kozlov, and Secundov, νt-92, is modified and supplemented by an equation for the turbulence length scale. The advantages of the model developed here are demonstrated by computing a shear-free “boundary layer” on a flat plate, and the flow and heat transfer near the forward stagnation line of a circular cylinder. Both cases are known to be challenging for conventional turbulence models.

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A Computational Study of Convection Heat Transfer to CO2 at Supercritical Pressures in a Vertical Mini Tube

ASME 2nd International Conference on Microchannels and Minichannels ◽

10.1115/icmm2004-2348 ◽

2004 ◽

Cited By ~ 2

Author(s):

S. He ◽

P. X. Jiang ◽

Yi-Jun Xu ◽

Run-Fu Shi ◽

W. S. Kim ◽

...

Keyword(s):

Heat Transfer ◽

Eddy Viscosity ◽

Computational Study ◽

Convection Heat Transfer ◽

Turbulence Models ◽

Vertical Tube ◽

Convection Heat ◽

Flow Acceleration ◽

Turbulence Production ◽

The One

Computational simulations of experiments on turbulent convection heat transfer of carbon dioxide at supercritical pressures in a vertical tube of diameter 0.948 mm have been carried out using low-Reynolds number eddy viscosity turbulence models. The simulations were able to reproduce the general features exhibited in the experiments. The modelling study has provided valuable information on the detailed flow and turbulence fields. It has been shown that for mini tubes such as the one used in the current study, the buoyancy effect is generally insignificant. Heat transfer can be significantly impaired when the heating is strong. This is due to the reduced turbulence production, induced by the flow acceleration which is in turn caused by strong heating.

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Heat Transfer in a Suddenly Expanded Turbulent Flow Past a Porous Insert Using Linear and Non-Linear Eddy-Viscosity Models

Heat Transfer, Volume 6 ◽

10.1115/imece2002-39402 ◽

2002 ◽

Cited By ~ 1

Author(s):

Marcelo J. S. de Lemos ◽

Marcelo Assato

Keyword(s):

Heat Transfer ◽

Turbulent Flow ◽

Eddy Viscosity ◽

Control Volume ◽

Numerical Technique ◽

Turbulence Models ◽

Wall Functions ◽

Porous Insert ◽

Flow Past ◽

Non Linear

This work presents numerical results for heat transfer in turbulent flow past a backward-facing-step channel with a porous insert using linear and non-linear eddy viscosity macroscopic models. The non-linear turbulence models are known to perform better than classical eddy-diffusivity models due to their ability to simulate important characteristics of the flow. Parameters such as porosity, permeability and thickness of the porous insert are varied in order to analyze their effects on the flow pattern, particularly on the damping of the recirculating bubble after the porous insertion. The numerical technique employed for discretizing the governing equations is the control-volume method. The SIMPLE algorithm is used to correct the pressure field. Wall functions for velocity and temperature are used in order to bypass fine computational close to the wall. Comparisons of results simulated with both linear and non-linear turbulence models are presented.

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Numerical Investigation of Flow and Heat Transfer Characteristics in Wire-Wrap Tight Lattice 19-Rod Bundle

Volume 3: Nuclear Safety and Security; Codes, Standards, Licensing and Regulatory Issues; Computational Fluid Dynamics and Coupled Codes ◽

10.1115/icone21-15832 ◽

2013 ◽

Author(s):

Minggang Li ◽

Jun Wang ◽

Changhua Nie ◽

Xiao Yan ◽

Yanping Huang ◽

...

Keyword(s):

Heat Transfer ◽

Friction Factor ◽

Eddy Viscosity ◽

Turbulence Models ◽

Heat Transfer Characteristics ◽

Transfer Velocity ◽

Transfer Characteristics ◽

Rod Bundle ◽

Flow And Heat Transfer ◽

Tight Lattice

Flow and heat transfer characteristics in wire-wrap tight lattice rod bundle have been investigated through CFD code ANSYS CFX 13.0. The bundle consists of 19 fuel rods with triangular tight lattice configuration. The rod ratio of rod pitch to rod diameter is 1.167. Four wires with a diameter of 0.5 mm are helically wrapped on the surface of each fuel rod. The ratio of wire-wrap helical pitch to the rod diameter is varied from 27.5 to 52.5. Through simulating wire-wrap 3-rod bundle with tetrahedron and hexahedron grid systems, the grid system which applies to simulating the wire-wrap tight lattice rod bundle has been obtained. The predicted results of eddy viscosity based turbulence models (k–ε, SST) and Reynolds stress turbulence models (BSL, SSG) are compared with each other and several experimental correlations for friction factor and Nusselt number. The predicted results of all the turbulence models are almost the same in some respects, but the friction factor predicted by the eddy viscosity models is higher than that predicted by the RSM. The effect of wire-wrap on pressure drop, friction factor, secondary flow, heat transfer, velocity distribution and temperature distribution in different subchannels (interior, edge and corner) has been analyzed by comparing with those of the bare rod bundle. The effect of wire-wrap pitch on the flow and heat transfer characteristics has also been studied.

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Computations of Flow Field and Heat Transfer in a Stator Vane Passage Using the v2¯−f Turbulence Model

Journal of Turbomachinery ◽

10.1115/1.1929820 ◽

2005 ◽

Vol 127 (3) ◽

pp. 627-634 ◽

Cited By ~ 11

Author(s):

A. Sveningsson ◽

L. Davidson

Keyword(s):

Heat Transfer ◽

Flow Field ◽

Turbulence Model ◽

Eddy Viscosity ◽

Fluid Motion ◽

Three Dimensional ◽

Turbulence Models ◽

Mean Flow ◽

Stator Vane ◽

Good Agreement

In this study three-dimensional simulations of a stator vane passage flow have been performed using the v2¯−f turbulence model. Both an in-house code (CALC-BFC) and the commercial software FLUENT are used. The main objective is to investigate the v2¯−f model’s ability to predict the secondary fluid motion in the passage and its influence on the heat transfer to the end walls between two stator vanes. Results of two versions of the v2¯−f model are presented and compared to detailed mean flow field, turbulence, and heat transfer measurements. The performance of the v2¯−f model is also compared with other eddy-viscosity-based turbulence models, including a version of the v2¯−f model, available in FLUENT. The importance of preventing unphysical growth of turbulence kinetic energy in stator vane flows, here by use of the realizability constraint, is illustrated. It is also shown that the v2¯−f model predictions of the vane passage flow agree well with experiments and that, among the eddy-viscosity closures investigated, the v2¯−f model, in general, performs the best. Good agreement between the two different implementations of the v2¯−f model (CALC-BFC and FLUENT) was obtained.

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Computations of Flow Field and Heat Transfer in a Stator Vane Passage Using the v2–f Turbulence Model

Volume 3: Turbo Expo 2004 ◽

10.1115/gt2004-53586 ◽

2004 ◽

Cited By ~ 2

Author(s):

Andreas Sveningsson ◽

Lars Davidson

Keyword(s):

Heat Transfer ◽

Flow Field ◽

Turbulence Model ◽

Eddy Viscosity ◽

Fluid Motion ◽

Three Dimensional ◽

Turbulence Models ◽

Mean Flow ◽

Stator Vane ◽

Good Agreement

In this study three-dimensional simulations of a stator vane passage flow have been performed using the v2–f turbulence model. Both an in-house code (CALC-BFC) and the commercial software Fluent are used. The main objective is to investigate the v2–f model’s ability to predict the secondary fluid motion in the passage and its influence on the heat transfer to the endwalls between two stator vanes. Results of two versions of the v2–f model are presented and compared with detailed mean flow field, turbulence and heat transfer measurements. The performance of the v2–f model is also compared with other eddy-viscosity based turbulence models, including a version of the v2–f model, available in Fluent. The importance of preventing unphysical growth of turbulence kinetic energy in stator vane flows, here by use of the realizability constraint, is illustrated. It is also shown that the v2–f model predictions of the vane passage flow agree well with experiments and that, amongst the eddy-viscosity closures investigated, the v2–f model in general performs the best. Good agreement between the two different implementations of the v2–f model (CALC-BFC and Fluent) was obtained.

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Rough Surface Wall Function Treatment With Single Equation Turbulence Models

Journal of Fluids Engineering ◽

10.1115/1.4036245 ◽

2017 ◽

Vol 139 (8) ◽

Cited By ~ 2

Author(s):

U. Goldberg ◽

P. Batten

Keyword(s):

Heat Transfer ◽

Kinetic Energy ◽

Distance Function ◽

Eddy Viscosity ◽

Rough Surfaces ◽

Turbulence Models ◽

Single Equation ◽

Current Approach ◽

Wall Function ◽

Wall Distance

Most literature in the area of turbulent flow over rough surfaces discusses methods for turbulence models based on two or more transport equations, one of which is that for turbulence kinetic energy which supplies k that is heavily used for the rough wall treatment. However, many aeronautical engineers routinely use single equation turbulence models which solve directly for eddy viscosity and do not involve k. The present work proposes methods by which such one-equation models can predict flow cases which include multiple rough surfaces. The current approach does not impose changes to the wall distance function, should such a function be necessary. Several examples show that the proposed method is able to produce good predictions of both skin friction and heat transfer along rough surfaces. While results are not always as accurate as those predicted by turbulence models which solve for k, especially if detached or wake-like flow regions exist, accompanied by a significant increase in eddy viscosity, the single-equation models are able to provide predictions at least good enough for preliminary studies.

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