Magnetohydrodynamic Effects Upon Heat Transfer for Laminar Flow Across a Flat Plate

1960 ◽  
Vol 82 (2) ◽  
pp. 87-93 ◽  
Author(s):  
R. D. Cess
Keyword(s):  
Heat Transfer ◽  
Laminar Flow ◽  
Flat Plate ◽  
Free Stream ◽  
Frictional Heating ◽  
Convection Heat Transfer ◽  
Constant Heat Flux ◽  
Stream Velocity ◽  
Electrically Conducting ◽  
Prandtl Numbers

Forced-convection heat transfer for laminar flow of electrically conducting fluids across a flat plate is considered for a magnetic field of constant inductance acting normal to the free stream velocity and fixed relative to the plate. The boundary condition on the surface of the plate is taken to be either a constant temperature or constant heat flux, and solutions are presented for the following cases: (a) Fluids having a Prandtl number of unity for which both Joule heating and frictional heating are accounted for; (b) fluids having moderate and large Prandtl numbers for negligible Joule and frictional heating; and (c) fluids having low Prandtl numbers for negligible frictional heating.

An Experimental Study of Mixed, Forced, and Free Convection Heat Transfer From a Horizontal Flat Plate to Air

1982 ◽  
Vol 104 (1) ◽  
pp. 139-144 ◽  
Author(s):  
X. A. Wang
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Flat Plate ◽  
Free Stream ◽  
Convection Heat Transfer ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Stream Velocity ◽  
Heated Plate ◽  
Buoyancy Effect

A heated flat plate is tested in a wind tunnel to study mixed convection in both upward and downward positions. It is found that the local heat transfer coefficient is strongly dependent on the free stream velocity and the temperature difference between the surface and the free stream. The buoyancy effect is more pronounced for the heated plate facing upward. This paper correlates the experimental data in terms of Nusselt, Grashof, and Reynolds numbers. The points of onset of instability caused by the buoyancy effect are also examined and correlated in terms of the dimensionless groups. Experimental data are compared with analysis documented in the literature, and the agreement is found satisfactory.

Heat Transfer in the Laminar Boundary Layer Over an Impulsively Started Flat Plate

1975 ◽  
Vol 97 (3) ◽  
pp. 482-484 ◽  
Author(s):  
C. B. Watkins
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Laminar Flow ◽  
Flat Plate ◽  
Constant Temperature ◽  
Laminar Boundary Layer ◽  
Temperature Difference ◽  
Thermal Boundary Layer ◽  
Numerical Solutions ◽  
Prandtl Numbers

Numerical solutions are described for the unsteady thermal boundary layer in incompressible laminar flow over a semi-infinite flat plate set impulsively into motion, with the simultaneous imposition of a constant temperature difference between the plate and the fluid. Results are presented for several Prandtl numbers.

Laminar Forced Convection of Various Nanofluids in Sudden Expansion Channels Under Constant Heat Flux: A CFD Study

2019 ◽  
Vol 11 (05) ◽  
pp. 1950049 ◽  
Author(s):  
Bahadir Acar
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Laminar Flow ◽  
Forced Convection ◽  
Pure Water ◽  
Convective Heat Transfer Coefficient ◽  
Convection Heat Transfer ◽  
Constant Heat Flux ◽  
Sudden Expansion ◽  
Ansys Fluent

In the present work, forced convection heat transfer was investigated numerically for the fully developed fluid flow of incompressible viscous laminar flow under the constant wall heat flux in sudden expansion channels. Various fluids were used with different concentration of nanoparticle such as Al2O3, TiO2, ZnO, CuO, SiO2. These nanoparticles were dispersed with the range of 0.5–2% volume concentrations in pure water to form stable suspensions of nanofluids. The flow assumed to be uniform in the channel inlet and numerical computations were performed for the fully developed laminar flow conditions. Ansys Fluent 16.1 code, based on finite volume approach was used to calculate the governing continuity, momentum and energy equations. Effect of the Re numbers (100[Formula: see text]Re[Formula: see text]500), nanoparticle volume concentration (0.5%[Formula: see text]2.0%) and nanofluid type on the flow and heat transfer characteristics such as convective heat transfer coefficient, Nu number, friction factor and pressure drop has been investigated. Al2O3/water nanofluid was found better when compared the other references working fluids by means of heat transfer enhancement.

Heat Transfer Across a Linearly Accelerated or Decelerated Laminar Boundary Layer

1965 ◽  
Vol 87 (3) ◽  
pp. 403-408 ◽  
Author(s):  
A. R. Bu¨yu¨ktu¨r ◽  
J. Kestin
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Laminar Boundary Layer ◽  
Free Stream ◽  
Frictional Heat ◽  
Stream Velocity ◽  
Transfer Rates ◽  
Boundary Layer Equations ◽  
Constant Coefficients ◽  
Prandtl Numbers

The paper presents solutions to the boundary-layer equations for heat-transfer rates into an accelerated and decelerated boundary layer in the presence of a linearly varying free-stream velocity. The equations are solved for the case of constant coefficients with frictional heat neglected, but over a range of Prandtl numbers.

The Effect of a Nonisothermal Free Stream on Boundary-Layer Heat Transfer

1959 ◽  
Vol 26 (2) ◽  
pp. 161-165
Author(s):  
E. M. Sparrow ◽  
J. L. Gregg
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Exact Solution ◽  
Energy Equation ◽  
Free Stream ◽  
Convection Heat Transfer ◽  
Stream Temperature ◽  
Convection Heat ◽  
Prandtl Numbers ◽  
Laminar Forced Convection

Abstract An analysis is made for laminar forced-convection heat transfer from a flat plate to a nonisothermal free stream. An exact solution of the boundary-layer energy equation is found for the situation of linearly varying free-stream temperature. Numerical calculations are carried out for Prandtl numbers in the range 0.01 ⩽ Pr ⩽ 50. Results are presented for the change in heat transfer due to the variation in free-stream temperature. This effect decreases with increasing Prandtl number.

A Numerical Solution for Laminar-Flow Heat Transfer in Circular Tubes With Axial Conduction and Developing Thermal and Velocity Fields

1967 ◽  
Vol 89 (1) ◽  
pp. 11-16 ◽  
Author(s):  
R. K. McMordie ◽  
A. F. Emery
Keyword(s):  
Heat Transfer ◽  
Laminar Flow ◽  
Constant Heat Flux ◽  
Velocity Fields ◽  
Constant Heat ◽  
Axial Conduction ◽  
Circular Tubes ◽  
Flow Heat ◽  
Prandtl Numbers ◽  
Radial Convection

This paper describes a numerical calculation of the local Nusselt number for laminar flow in a tube with axial conduction, radial convection, and simultaneously developing thermal and velocity profiles. The results are given for a constant heat flux at the wall and Prandtl numbers from 0.005 to 0.03 with a Pr = 0.7 used to compare with Kays solution.

Investigation of the Variation of Point Unit Heat-Transfer Coefficients for Laminar Flow Over an Inclined Flat Plate

1949 ◽  
Vol 16 (1) ◽  
pp. 1-8
Author(s):  
R. M. Drake
Keyword(s):  
Heat Transfer ◽  
Laminar Flow ◽  
Flat Plate ◽  
Forced Convection ◽  
Convection Heat Transfer ◽  
Specific Rate ◽  
Angle Of Incidence ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Full Explanation

Abstract Many applications of heat-transfer phenomena by forced convection require a knowledge of heat transfer from simple geometric bodies like the flat plate. Investigations of the flat plate have been limited, in general, to studies of isothermal plates of 0-deg angle of incidence and in laminar flow. The amount of data concerning investigations on turbulent flow, nonisothermal plates or inclined plates is quite small. It is the intent of this paper to provide information on the heat transfer from a nonisothermal inclined flat plate in laminar flow. It is shown herein that forced-convection heat-transfer data for an inclined nonisothermal flat plate with a constant specific rate of heat flow can be correlated and represented by an equation of the type (1)NuxReL=C(xL)n for laminar flow. It is further shown that this equation is similar in slope to the theoretical equation of the type (2)NuxReL=C2(xL)m+12 for an isothermal plate in laminar flow, but is larger by 30 per cent in absolute value. This variance can be partly explained by an analysis of the behavior of a nonisothermal plate as opposed to an isothermal one, but this analysis leaves much to be desired, so that the full explanation is at present unknown.

Effect of Free-Stream Turbulence on Flat-Plate Heat Flux Signals: Spectra and Eddy Transport Velocities

1996 ◽  
Vol 118 (3) ◽  
pp. 461-467 ◽  
Author(s):  
R. W. Moss ◽  
M. L. G. Oldfield
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Flat Plate ◽  
Free Stream ◽  
Cfd Modeling ◽  
Stream Velocity ◽  
Free Stream Turbulence ◽  
Eddy Structure ◽  
Boundary Layer Turbulence ◽  
Nusselt Numbers

An experimental study of the eddy structure in a flat-plate turbulent boundary layer with significant levels of free-stream turbulence is presented. This is relevant to the enhancement of turbomachinery heat transfer by turbulence and should lead to more realistic CFD modeling. Previous measurements showed that Nusselt numbers may be increased by up to 35 percent, and that this increase depended on turbulence integral length scale as well as intensity. The new results described here provide an insight into the mechanism responsible. Thin film gages and hot wires were used to take simultaneous high-frequency measurements of fluctuating heat transfer rates to the flat plate and the fluctuating flow velocity in the free stream and boundary layer. Spectra and correlation analysis shows that the turbulent eddy structure of the boundary layer is dominated by the free-stream turbulence at intensities of 3 percent and above. Eddies in the boundary layer mimicked those in the free stream and convected at the free-stream velocity U, rather than the ∼0.8U characteristic of boundary layers. The main heat transfer enhancing mechanism is due to the penetration of free-stream turbulent eddies deep into the boundary layer, rather than enhancement of existing boundary layer turbulence.

Heat Transfer to Laminar Flow Across a Flat Plate With a Nonsteady Surface Temperature

1961 ◽  
Vol 83 (3) ◽  
pp. 274-279 ◽  
Author(s):  
R. D. Cess
Keyword(s):  
Heat Transfer ◽  
Laminar Flow ◽  
Surface Temperature ◽  
Flat Plate ◽  
Large Time ◽  
Convection Heat Transfer ◽  
Time History ◽  
Heat Transfer Process ◽  
History Of ◽  
Nonsteady Heat Transfer

Forced convection heat transfer is considered for laminar flow across a flat plate whose surface temperature varies with time. The case analyzed first is that of a step change in surface temperature, and series solutions are obtained which apply for both small and large time. These series results are used to construct an approximate solution which describes the entire time-history of the nonsteady heat-transfer process, and it is found that the results agree closely with an envelope composed of pure transient conduction and steady-state convection solutions. The analysis is then generalized to include any prescribed variation of surface temperature with time.

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