Steady Free Convection to a Flat Plate With Uniform Surface Heat Flux and Nonuniform Acceleration

1964 ◽  
Vol 86 (4) ◽  
pp. 562-563 ◽  
Author(s):  
Robert Lemlich ◽  
Joseph Vardi
Keyword(s):  
Boundary Layer ◽  
Heat Flux ◽  
Surface Heat Flux ◽  
Integral Method ◽  
Boundary Layer Thickness ◽  
Local Heat Transfer ◽  
Classical Case ◽  
Local Heat ◽  
Turbulent Boundary Layers ◽  
Surface Heat

Solutions for laminar and turbulent boundary layers are arrived at by means of the integral method. These show that the nonuniformity in acceleration results in distributions (along the plate) for the local heat transfer coefficient and boundary layer thickness which differ from the classical case of uniform acceleration. For the laminar boundary layer under nonuniform acceleration, these distributions yield results for uniform surface heat flux which are identical with those for uniform surface temperature. However, for the turbulent boundary layer, this identity does not apply.

A New Experimental Technique for Measuring Surface Heat Transfer Coefficients Using Uncalibrated Liquid Crystals

1999 ◽  
Author(s):  
Wayne N. O. Turnbull ◽  
Patrick H. Oosthuizen
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Experimental Technique ◽  
Surface Heat Flux ◽  
Local Heat ◽  
Surface Heat ◽  
Phase Delay ◽  
Transfer Coefficients ◽  
Periodic Surface ◽  
Heat Transfer Coefficients

Abstract A new experimental technique has been developed that permits the determination of local surface heat transfer coefficients on surfaces without requirement for calibration of the temperature-sensing device. The technique uses the phase delay that develops between the surface temperature response and an imposed periodic surface heat flux. This phase delay is dependent upon the thermophysical properties of the model, the heat flux driving frequency and the local heat transfer coefficient. It is not a function of magnitude of the local heat flux. Since only phase differences are being measured there is no requirement to calibrate the temperature sensor, in this instance a thermochromic liquid crystal. Application of a periodic surface heat flux to a flat plate resulted in a surface colour response that was a function of time. This response was captured using a standard colour CCD camera and the phase delay angles were determined using Fourier analysis. Only the 8 bit G component of the captured RGB signal was required, there being no need to determine a Hue value. From these experimentally obtained phase delay angles it was possible to determine heat transfer coefficients that compared well with those predicted using a standard correlation.

Boundary-Layer Disturbances and Surface Heat-Flux Profiles on a Cooled Slender Cone

2022 ◽  
Author(s):  
Laura A. Paquin ◽  
Shaun Skinner ◽  
Stuart J. Laurence
Keyword(s):  
Boundary Layer ◽  
Heat Flux ◽  
Surface Heat Flux ◽  
Surface Heat

Boundary-layer flow of a micropolar fluid on a continuous flatplate moving in a parallel stream with uniform surface heat flux

2007 ◽  
Vol 85 (8) ◽  
pp. 869-878 ◽  
Author(s):  
A Ishak ◽  
R Nazar ◽  
I Pop
Keyword(s):  
Boundary Layer ◽  
Heat Flux ◽  
Boundary Layer Flow ◽  
Surface Heat Flux ◽  
Micropolar Fluid ◽  
Free Stream ◽  
Velocity Ratio ◽  
Skin Friction Coefficient ◽  
Surface Heat ◽  
Layer Flow

The laminar boundary-layer flow of a micropolar fluid on a fixed or continuously moving flat plate with uniform surface heat flux is investigated. The plate is assumed to move in the same oropposite direction to the free stream. The resulting system of nonlinear ordinary differential equations is solved numerically using the Keller-box method. Numerical results are obtained for the skin-friction coefficient and the local Nusselt number as well as the velocity, microrotation, and temperature profiles for some values of the governing parameters, namely, the velocity ratio parameter, material parameter, and Prandtl number. The results indicate that dual solutions exist when the plate and the free stream move in the opposite directions.PACS No.: 47.15.Cb

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