scholarly journals NUMERICAL ANALYSIS OF CONJUGATE HEAT TRANSFER INSIDE A THERMAL BOUNDARY LAYER CONSIDERING THE EFFECTS OF A FREE STREAM VELOCITY AND A THERMOCOUPLE POSITION

2013 ◽  
Vol 18 (1) ◽  
pp. 77-82
Author(s):  
B.J. Jeon ◽  
J.A. Lee ◽  
H.G. Choi
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Numerical Analysis ◽  
Thermal Boundary Layer ◽  
Conjugate Heat Transfer ◽  
Free Stream ◽  
Free Stream Velocity ◽  
Stream Velocity

scholarly journals Prediction of Heat Transfer From Laminar Boundary Layers, With Emphasis on Large Free-Stream Velocity Gradients and Highly Cooled Walls

1966 ◽  
Vol 88 (3) ◽  
pp. 249-256 ◽  
Author(s):  
L. H. Back ◽  
A. B. Witte
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Shear Stress ◽  
Velocity Gradient ◽  
Free Stream ◽  
Variable Density ◽  
Similarity Solutions ◽  
Free Stream Velocity ◽  
Stream Velocity ◽  
Gradient Parameter

Laminar boundary-layer heat transfer and shear-stress predictions from existing similarity solutions are extended in an approximate way to perfect gas flows with a large free-stream velocity gradient parameter β and variable density-viscosity product ρμ across the boundary layer resulting from a highly cooled wall. The dimensionless enthalpy gradient at the wall gw′, to which the heat flux is related, is found not to vary appreciably with β. Thus the application of similarity solutions on a local basis to predict heat transfer from accelerated flows to an arbitrary surface may be a reasonable approximation involving a minimum amount of calculation time. Unlike gw′, the dimensionless velocity gradient at the wall fw″, to which the shear stress is related, is strongly dependent on β.

Skin Friction and Heat Transfer for Laminar Boundary-Layer Flow With Variable Properties and Variable Free-Stream Velocity

1953 ◽  
Vol 20 (3) ◽  
pp. 415-421
Author(s):  
S. Levy ◽  
R. A. Seban
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Prandtl Number ◽  
Skin Friction ◽  
Laminar Boundary Layer ◽  
Boundary Layer Flow ◽  
Free Stream ◽  
Free Stream Velocity ◽  
Stream Velocity ◽  
Layer Flow

Abstract Numerical solutions of the momentum and energy equations are presented for particular types of laminar boundary-layer flow analogous to the Hartree “wedge flows.” Variation of the viscosity and of the thermal conductivity is considered under the circumstances of no dissipation, favorable pressure gradient, and the product of conductivity and density a constant. The solution is based on approximate representations of the velocity and temperature profiles in the boundary layer and these are of such character that the labor of calculation is minimized and the accuracy of the results preserved. The differential equations are reduced to two algebraic equations which rapidly yield the skin friction and the heat transfer in terms of the wall to free-stream temperature ratio for the desired value of Prandtl number. Numerical results are given for a range of wedge flows with gases of Prandtl number 0.70 and 1.0. These results reveal that when the free-stream velocity is variable the temperature difference between the wall and the free stream exerts a substantial effect on the velocity distribution in the boundary layer and on the skin-friction coefficient. Alternatively, the heat-transfer coefficient is not affected radically. A calculation method is presented for the determination of the heat transfer and skin friction for a flow with an arbitrary variation of velocity over an isothermal surface. This method utilizes the results of the present analysis for the variable property wedge flows.

The thermal boundary layer on a non-isothermal surface with non-uniform free stream velocity

1958 ◽  
Vol 4 (3) ◽  
pp. 321-329 ◽  
Author(s):  
E. M. Sparrow
Keyword(s):  
Boundary Layer ◽  
Exact Solution ◽  
Wall Temperature ◽  
Thermal Boundary Layer ◽  
Free Stream ◽  
Temperature Data ◽  
Free Stream Velocity ◽  
Stream Velocity ◽  
Universal Functions ◽  
Isothermal Surface

A formally exact solution for the thermal boundary layer on a non-isothermal surface subjected to non-uniform free stream velocity is presented in the form of a series. It is demonstrated that the solution can be recast in terms of universal functions, which are independent of the wall temperature data of particular problems, and which depend only on a single parameter characterizing the variation of the free stream velocity.

Effectiveness and Heat Transfer for a Turbulent Boundary Layer With Tangential Injection and Variable Free-Stream Velocity

1962 ◽  
Vol 84 (3) ◽  
pp. 235-242 ◽  
Author(s):  
R. A. Seban ◽  
L. H. Back
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Free Stream ◽  
Free Stream Velocity ◽  
Stream Velocity ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Air Stream ◽  
External Stream

The effectiveness and the heat transfer have been measured in a system involving the tangential injection of air from a single spanwise slot into the turbulent boundary layer of an external air stream, with the velocity of the external stream increasing in a way that concentrated the acceleration in a region downstream of the initial mixing zone. The effectiveness was changed but little from the value that would have existed had the free-stream velocity remained at its initial value and both temperature profiles and analytical considerations show that this invariability of the effectiveness is associated with thermal boundary-layer thicknesses that are much larger than the hydrodynamic thicknesses. Heat-transfer coefficients are shown to be predictable from existing information provided that the momentum thickness Reynolds number is large enough.

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