Turbulent Heat Transfer in Plane Couette Flow

Heat transfer in a fully developed plane Couette flow for different Prandtl number fluids was studied using numerical simulations. The flow field was created by two infinite planes moving at the same velocity, but in opposite directions, forming a region of constant total shear stress. Heat markers were released into the flow from the channel wall, and the ground level temperature was calculated for dispersion from continuous line sources of heat. In addition, the temperature profile across the channel was synthesized from the behavior of these continuous line sources. It was found that the heat transfer coefficient for Couette flow is higher than that in channel flow for the same Prandtl numbers. Correlations were also obtained for the heat transfer coefficient for any Prandtl number ranging from 0.1 to 15,000 in fully developed turbulence.

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Turbulent Heat Transfer in Plane Couette Flow

Volume 2, Parts A and B ◽

10.1115/ht-fed2004-56130 ◽

2004 ◽

Author(s):

Phuong M. Le ◽

Dimitrios V. Papavassiliou

Keyword(s):

Heat Transfer ◽

Flow Field ◽

Prandtl Number ◽

Couette Flow ◽

Channel Flow ◽

Turbulent Dispersion ◽

Turbulent Heat Transfer ◽

Turbulent Heat ◽

Turbulence Structure ◽

Plane Couette Flow

Direct numerical simulations of a turbulent plane Couette flow are combined with Lagrangian scalar tracking of thermal markers that are released in the flow field to determine the behavior of an instantaneous scalar line source located at the wall. The resulting probability density functions are used to calculate the behavior of instantaneous line sources of heat at the wall of the channel. The method is applied for fluids with a range of molecular Prandtl number, Pr, between 0.1 and 15,000, giving emphasis on the high Pr cases. The issues that are investigated are the effect of the Pr on turbulent dispersion, and the effect of the turbulence structure on turbulent heat transfer. The flow field for plane Couette flow is fundamentally different than that for channel flow, because the whole Couette flow domain is a constant stress region that forms an extensive logarithmic layer. For an instantaneous source at the wall, it is found that in both the channel flow and the Couette flow cases there are similar stages of development of the marker cloud that depend on the Prandtl number. This dependence becomes stronger as the Pr increases. However, this similarity is only qualitative.

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DNS OF TURBULENT HEAT TRANSFER IN PLANE COUETTE FLOW

Equipment ◽

10.1615/ihtc13.p1.200 ◽

2006 ◽

Author(s):

S. Hane ◽

T. Tsukahara ◽

K. Iwamoto ◽

H. Kawamura

Keyword(s):

Heat Transfer ◽

Couette Flow ◽

Turbulent Heat Transfer ◽

Turbulent Heat ◽

Plane Couette Flow

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Turbulent Heat Transfer in the Separated, Reattached, and Redevelopment Regions of a Circular Tube

Journal of Heat Transfer ◽

10.1115/1.3691456 ◽

1966 ◽

Vol 88 (1) ◽

pp. 131-136 ◽

Cited By ~ 89

Author(s):

K. M. Krall ◽

E. M. Sparrow

Keyword(s):

Heat Transfer ◽

Reynolds Number ◽

Heat Transfer Coefficient ◽

Transfer Coefficient ◽

Flow Separation ◽

Circular Tube ◽

Turbulent Pipe Flow ◽

Turbulent Heat Transfer ◽

Working Fluid ◽

The Heat Transfer Coefficient

Experiments were performed to determine the effect of flow separation on the heat-transfer characteristics of a turbulent pipe flow. The flow separation was induced by an orifice situated at the inlet of an electrically heated circular tube. The degree of flow separation was varied by employing orifices of various bore diameters. Water was the working fluid. The Reynolds number and the Prandtl number, respectively, ranged from 10,000 to 130,000 and from 3 to 6. The measurements show that the local heat-transfer coefficients in the separated, reattached, and redevelopment regions are several times as large as those for a fully developed flow. For instance, at the point of reattachment, the coefficients were 3 to 9 times greater than the corresponding fully developed values. In general, the increase of the heat-transfer coefficient owing to flow separation is accentuated as the Reynolds number decreases. The point of flow reattachment, which corresponds to a maximum in the distribution of the heat-transfer coefficient, was found to occur from 1.25 to 2.5 pipe dia from the onset of separation.

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Numerical Study of Turbulent Heat Transfer in Annular Pipe with Sudden Contraction

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.465-466.461 ◽

2013 ◽

Vol 465-466 ◽

pp. 461-466 ◽

Cited By ~ 1

Author(s):

Hussein Togun ◽

Tuqa Abdulrazzaq ◽

S.N. Kazi ◽

A. Badarudin ◽

Mohd Khairol Anuar Ariffin

Keyword(s):

Heat Transfer ◽

Reynolds Number ◽

Heat Transfer Coefficient ◽

Transfer Coefficient ◽

Turbulent Heat Transfer ◽

Recirculation Region ◽

Turbulent Heat ◽

Contraction Ratio ◽

Sudden Contraction ◽

Annular Pipe

Turbulent heat transfer to air flow in annular pipe with sudden contraction numerically studied in this paper. The k-ε model with finite volume method used to solve continuity, moment and energy equations. The boundary condition represented by uniform and constant heat flux on inner pipe with range of Reynolds number varied from 7500 to 30,000 and contraction ratio (CR) varied from 1.2 to 2. The numerical result shows increase in local heat transfer coefficient with increase of contraction ratio (CR) and Reynolds number. The maximum of heat transfer coefficient observed at contraction ratio of 2 and Reynolds number of 30,000 in compared with other cases. Also pressure drop coefficient noticed rises with increase contraction ratio due to increase of recirculation flow before and after the step height. In contour of velocity stream line can be seen that increase of recirculation region with increase contraction ratio (CR).

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Experimental Study of Heat Transfer Enhancement through a Tube with Wire-Coil Inserts at Low Turbulent Reynolds Number

International Journal of Engineering Materials and Manufacture ◽

10.26776/ijemm.03.03.2018.01 ◽

2018 ◽

Vol 3 (3) ◽

pp. 122-133

Author(s):

Mohammad Zoynal Abedin ◽

M. A. Rashid Sarkar

Keyword(s):

Heat Transfer ◽

Heat Transfer Coefficient ◽

Transfer Coefficient ◽

Test Section ◽

Reynolds Numbers ◽

Turbulent Heat Transfer ◽

Turbulent Heat ◽

Low Reynolds Numbers ◽

Wire Coil ◽

Low Reynolds

This paper reports an experimental analysis to investigate the enhancement of turbulent heat transfer flow of air through one smooth tube and four different tubes with wire-coil inserts (Pitches, Pc = 12, 24, 40, and 50 mm with corresponding helix angles, a =100, 200, 350, and 450, respectively) at low Reynolds numbers ranging from 6000 to 22000. The test section of the tube was electrically heated and was cooled by fully developed turbulent air flow. The performance of the tubes was evaluated by considering the condition of maximizing heat transfer rate. From the measured data, the heat transfer characteristics such as heat transfer coefficient, effectiveness and Nusselt number, and the fluid flow behaviours such as friction factor, pressure drops and pumping power along the axial distance of the test section were analyzed at those Reynolds numbers for the tubes. The results indicated that for the tubes with wire-coil inserts at low Reynolds numbers, the turbulent heat transfer coefficient might be as much as two-folds higher, the friction factors could be as much as four-folds higher, and the effectiveness might be as much as 1.25 folds higher than those for the smooth tube with similar flow conditions. A correlation was also developed to predict the turbulent heat transfer coefficients through the tubes at low Reynolds numbers.

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Heat Transfer With Very High Free-Stream Turbulence: Part II—Analysis of Results

Journal of Heat Transfer ◽

10.1115/1.2911890 ◽

1992 ◽

Vol 114 (4) ◽

pp. 834-839 ◽

Cited By ~ 32

Author(s):

P. K. Maciejewski ◽

R. J. Moffat

Keyword(s):

Heat Transfer ◽

Heat Transfer Coefficient ◽

Free Stream ◽

Turbulent Heat Transfer ◽

Turbulent Heat ◽

Simple Correlation ◽

Free Stream Turbulence ◽

Analysis Of Results ◽

The Heat Transfer Coefficient ◽

Very High

Correlations describing the effect of free-stream turbulence on heat transfer have been offered by Simonich and Bradshaw (1978), Pedisius et al. (1983), and Blair (1983a), but they fail to describe the present data. The present data can be represented by a function of St, St/St0, ReΔ2Tu, and Λ/Δ2 within ±20 percent, but equally well by a simple correlation relating the rms fluctuating velocity in the free stream, u′, to the heat transfer coefficient, h. A new Stanton number, St′, based on u′max, the maximum standard deviation in the streamwise component of velocity found in the wall affected region, collects the data of Blair (1983b), Pedisius et al. (1983), Vogel (1984), MacArthur (1986), and Hollingsworth et al. (1989), as well as the data from the present experiment, all within ± 15 percent. The fact that h can be expressed as a function of local u′ alone suggests the possibility of geometry-independent correlations for turbulent heat transfer.

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Numerical Prediction of Turbulent Flow and Heat Transfer Within Ducts of Cross-Shaped Cross Section

Journal of Heat Transfer ◽

10.1115/1.3247021 ◽

1986 ◽

Vol 108 (4) ◽

pp. 841-847 ◽

Cited By ~ 3

Author(s):

A. Nakayama ◽

H. Koyama

Keyword(s):

Heat Transfer ◽

Heat Transfer Coefficient ◽

Transfer Coefficient ◽

Cross Section ◽

Secondary Flows ◽

Turbulent Heat Transfer ◽

Parallel Plates ◽

Reynolds Analogy ◽

The Heat Transfer Coefficient ◽

Shaped Cross Section

Calculations were carried out for fully developed turbulent flows within ducts of cross-shaped cross section using the numerical method based on the pressure correction method developed by Patankar and Spalding. The Reynolds stress driven secondary flows were simulated successfully by Launder and Ying’s algebraic stress model coupled to the k–ε turbulence model. A parametric study was made on the friction and heat transfer characteristics in terms of the parameter α associated with the decrease in the cross-sectional area, namely, α = 0 for a square duct, and α → 1 for infinite parallel plates. Through performance evaluations, it has been found that both the Reynolds analogy factor and the heat transfer coefficient under equal pumping power decrease slightly, while the heat transfer coefficient obtained with equal mass flow rate increases appreciably with α, suggesting effective turbulent heat transfer within ducts of cross-shaped cross section.

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Turbulent Heat Transfer Measurements on a Wall With Concave and Cylindrical Dimples in a Square Channel

Volume 3: Turbo Expo 2002, Parts A and B ◽

10.1115/gt2002-30208 ◽

2002 ◽

Cited By ~ 20

Author(s):

S. W. Moon ◽

S. C. Lau

Keyword(s):

Heat Transfer ◽

Heat Transfer Coefficient ◽

Pressure Drop ◽

Transfer Coefficient ◽

Turbulent Heat Transfer ◽

Turbulent Heat ◽

Internal Cooling ◽

Experimental Conditions ◽

Square Channel ◽

Fully Developed Turbulent Flow

Dimpled surfaces may be considered for heat transfer enhancement in internal cooling of gas turbine airfoils. In this study, convective heat transfer and pressure drop for turbulent airflow in a square channel with a dimpled wall were examined. Experiments were conducted to determine the average heat transfer coefficient on the dimpled wall and the overall pressure drop across the channel, for nine concave and cylindrical dimples with various diameters and depths, and for Reynolds numbers (based on the channel hydraulic diameter) between 10,000 and 65,000. For the concave and cylindrical dimple configurations studied, the dimples were found to enhance the heat transfer coefficient by 70% (1.7 times) to over three times the value for fully developed turbulent flow through a smooth tube, with increase of the overall pressure drop of over four times. For both the concave and cylindrical dimples, heat transfer was enhanced more when the dimples covered a larger portion of the surface of the wall. The cylindrical dimples caused higher overall heat transfer coefficient (based on the projected area) and lower pressure drop than the concave dimples with the same diameters and depths. Thus, cylindrical dimple configuration may be a better alternative than concave dimples in enhancing heat transfer, for the experimental conditions and dimple configurations investigated. Further experiments are recommended to determine if cylindrical dimples of other dimensions also give higher thermal performances than concave dimples of the same dimensions, subjected to other flow and thermal boundary conditions, such as irregular channels with or without rotation.

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