An Approximate Method for Predicting Laminar Heat Transfer Between Parallel Plates Having Embedded Heat Sources

1995 ◽  
Vol 117 (1) ◽  
pp. 63-68 ◽  
Author(s):  
R. S. Figliola ◽  
P. G. Thomas
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Approximate Method ◽  
Numerical Solutions ◽  
Convection Heat Transfer ◽  
Flow Regimes ◽  
Experimental Result ◽  
Heat Sources ◽  
Parallel Plates ◽  
Two Dimensional Flow

An approximate method for predicting the forced convection heat transfer for flow between parallel plates having embedded, discrete heat sources on one or both sides is presented. The spacing between sources is considered as adiabatic and the two-dimensional flow is laminar. The characteristics of such a flow can be described as flow in the isolated plate, developing flow, and fully developed flow regimes. The analysis uses appropriate forms for the surface temperature and Nusselt number solutions for the flow regimes encountered. Superposition is then applied to develop the discrete array solution for temperature and Nusselt number regardless of the arbitrary and step nature of the boundary conditions. Comparisons to existing numerical solutions show good agreement to within five percent of the predicted temperatures. A direct simulation of an existing experimental result shows reasonable agreement in the Nusselt number solution. These results validate the methodology for practical use including electronic cooling applications.

Internal Laminar Heat Transfer With Gas-Property Variation

1971 ◽  
Vol 93 (4) ◽  
pp. 432-440 ◽  
Author(s):  
T. B. Swearingen ◽  
D. M. McEligot
Keyword(s):  
Heat Transfer ◽  
Numerical Solutions ◽  
Bulk Temperature ◽  
Parallel Plates ◽  
Temperature Dependent ◽  
Property Variation ◽  
Constant Wall Heat Flux ◽  
Mixed Mean ◽  
Two Dimensional Flow ◽  
Temperature Dependent Properties

The results of a numerical investigation of internal laminar heat transfer to a gas with temperature-dependent properties are reported. In this investigation the authors obtained numerical solutions to the coupled partial differential equations of continuity, energy, momentum, and integral continuity describing the two-dimensional flow of perfect gas between heated parallel plates. A sequence of numerical solutions was obtained for the case of constant wall heat flux with a fully developed velocity profile at the start of the heated section and pure forced convection. The results may be summarized by Nu=Nuconst.prop.+0.024(Q+)0.3(Gzm)0.75f·Rem=24(Twall/Tbulk) where the subscript “m” refers to properties evaluated at the local mixed-mean (or bulk) temperature.

Laminar Heat Transfer Between a Series of Parallel Plates With Surface-Mounted Discrete Heat Sources

1995 ◽  
Vol 117 (1) ◽  
pp. 52-62 ◽  
Author(s):  
S. H. Kim ◽  
N. K. Anand
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Thermal Resistance ◽  
Friction Factor ◽  
Thermal Performance ◽  
Average Nusselt Number ◽  
Computational Domain ◽  
Heat Sources ◽  
Parallel Plates ◽  
Independent Parameters

Two-dimensional laminar heat transfer between a series of parallel plates with surface mounted block heat sources was numerically studied. These channels resemble cooling passages of electronic equipment. Consideration was given only to periodically fully developed flow (PDF) and heat transfer. The computational domain was subjected to periodic condition in the streamwise direction and repeated condition in the cross-stream direction (double cyclic). The governing equations were solved by a finite volume technique. Calculations were made for a wide range of independent parameters (Re, ks/kf, s/w, d/w, H/w, and t/H). Consideration was given only to airflow (Pr=0.7). The friction factor was found to be a strong function of channel height and a weak function of block spacing. The thermal performance was studied in terms of the average Nusselt number and overall thermal resistance. For the most part, the thermal performance was independent of the Reynolds number, however, it deteriorated drastically for Re ≤ 500. The thermal resistance was found to decrease with an increase in substrate conductivity up to a particular value of ks/kf, and beyond this value thermal resistance did not decrease further. This value of ks/kf is a function of geometric parameters and occurs between 1 and 10. Correlations in terms of independent parameters were developed for friction factor, average Nusselt number, and thermal resistance.

Forced convection heat transfer study of a blunt-headed cylinder in non-Newtonian power-law fluids

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jaspinder Kaur ◽  
Roderick Melnik ◽  
Anurag Kumar Tiwari
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Drag Coefficient ◽  
Power Law ◽  
Average Nusselt Number ◽  
Convection Heat Transfer ◽  
Convection Heat ◽  
Total Drag ◽  
Shear Thinning Fluids ◽  
Power Law Fluids

Abstract In this present work, forced convection heat transfer from a heated blunt-headed cylinder in power-law fluids has been investigated numerically over the range of parameters, namely, Reynolds number (Re): 1–40, Prandtl number (Pr): 10–100 and power-law index (n): 0.3–1.8. The results are expressed in terms of local parameters, like streamline, isotherm, pressure coefficient, and local Nusselt number and global parameters, like wake length, drag coefficient, and average Nusselt number. The length of the recirculation zone on the rear side of the cylinder increases with the increasing value of Re and n. The effect of the total drag coefficient acting on the cylinder is seen to be higher at the low value of Re and its effect significant in shear-thinning fluids (n < 1). On the heat transfer aspect, the rate of heat transfer in fluids is increased by increasing the value of Re and Pr. The effect of heat transfer is enhanced in shear-thinning fluids up to ∼ 40% and it impedes it’s to ∼20% shear-thickening fluids. In the end, the numerical results of the total drag coefficient and average Nusselt number (in terms of J H −factor) have been correlated by simple expression to estimate the intermediate value for the new application.

Natural Convection From Protruding Heat Sources in a Channel

2003 ◽  
Author(s):  
Tunc Icoz ◽  
Qinghua Wang ◽  
Yogesh Jaluria
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Natural Convection ◽  
Rayleigh Scattering ◽  
Convection Heat Transfer ◽  
Separation Distance ◽  
Natural Convection Heat Transfer ◽  
Temperature Profiles ◽  
Heat Sources ◽  
Convection Heat

Natural convection has important implications in many applications like cooling of electronic equipment due to its low cost and easy maintenance. In the present study, two-dimensional natural convection heat transfer to air from multiple identical protruding heat sources, which simulate electronic components, located in a horizontal channel has been studied numerically. The fluid flow and temperature profiles, above the heating elements placed between an adiabatic lower plate and an isothermal upper plate, are obtained using numerical simulation. The effects of source temperatures, channel dimensions, openings, boundary conditions, and source locations on the heat transfer from and flow above the protruding sources are investigated. Different configurations of channel dimensions and separation distances of heat sources are considered and their effects on natural convection heat transfer characteristics are studied. The results show that the channel dimensions have a significant effect on fluid flow. However, their effects on heat transfer are found to be small. The separation distance is found to be an important parameter affecting the heat transfer rate. The numerical results of temperature profiles are compared with the experimental measurements performed using Filtered Rayleigh Scattering (FRS) technique in an earlier study, indicating good agreement. It is observed that adiabatic upper plate assumption leads to better temperature predictions than isothermal plate assumption.

Heat Transfer Investigation of a Tube Partially Wrapped by Metal Porous Layer as a Potential Novel Tube for Air Cooled Heat Exchangers

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
M. Mohammadpour-Ghadikolaie ◽  
M. Saffar-Avval ◽  
Z. Mansoori ◽  
N. Alvandifar ◽  
N. Rahmati
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Heat Transfer Rate ◽  
Porous Layer ◽  
Transfer Rate ◽  
Metal Foam ◽  
Convection Heat Transfer ◽  
Darcy Number ◽  
High Heat Transfer

Laminar forced convection heat transfer from a constant temperature tube wrapped fully or partially by a metal porous layer and subjected to a uniform air cross-flow is studied numerically. The main aim of this study is to consider the thermal performance of some innovative arrangements in which only certain parts of the tube are covered by metal foam. The combination of Navier–Stokes and Darcy–Brinkman–Forchheimer equations is applied to evaluate the flow field. Governing equations are solved using the finite volume SIMPLEC algorithm and the effects of key parameters such as Reynolds number, metal foam thermophysical properties, and porous layer thickness on the Nusselt number are investigated. The results show that using a tube which is fully wrapped by an external porous layer with high thermal conductivity, high Darcy number, and low drag coefficient, can provide a high heat transfer rate in the high Reynolds number laminar flow, increasing the Nusselt number almost as high as 16 times compared to a bare tube. The most important result of thisstudy is that by using some novel arrangements in which the tube is partially covered by the foam layer, the heat transfer rate can be increased at least 20% in comparison to the fully wrapped tube, while the weight and material usage can be considerably reduced.

Turbulent Heat Transfer Between a Series of Parallel Plates With Surface-Mounted Discrete Heat Sources

1994 ◽  
Vol 116 (3) ◽  
pp. 577-587 ◽  
Author(s):  
S. H. Kim ◽  
N. K. Anand
Keyword(s):  
Heat Transfer ◽  
Thermal Resistance ◽  
Electronic Equipment ◽  
Turbulent Heat Transfer ◽  
Turbulent Heat ◽  
Computational Domain ◽  
Heat Sources ◽  
Parallel Plates ◽  
Wide Range ◽  
Independent Parameters

Two-dimensional turbulent heat transfer between a series of parallel plates with surface mounted discrete block heat sources was studied numerically. The computational domain was subjected to periodic conditions in the streamwise direction and repeated conditions in the cross-stream direction (Double Cyclic). The second source term was included in the energy equation to facilitate the correct prediction of a periodically fully developed temperature field. These channels resemble cooling passages in electronic equipment. The k–ε model was used for turbulent closure and calculations were made for a wide range of independent parameters (Re, Ks/Kf, s/w, d/w, and h/w). The governing equations were solved by using a finite volume technique. The numerical procedure and implementation of the k–ε model was validated by comparing numerical predictions with published experimental data (Wirtz and Chen, 1991; Sparrow et al., 1982) for a single channel with several surface mounted blocks. Computations were performed for a wide range of Reynolds numbers (5 × 104–4 × 105) and geometric parameters and for Pr = 0.7. Substrate conduction was found to reduce the block temperature by redistributing the heat flux and to reduce the overall thermal resistance of the module. It was also found that the increase in the Reynolds number decreased the thermal resistance. The study showed that the substrate conduction can be an important parameter in the design and analysis of cooling channels of electronic equipment. Finally, correlations for the friction factor (f) and average thermal resistance (R) in terms of independent parameters were developed.

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