Laminar forced convection with sinusoidal wall heat flux distribution: axially periodic regime

1995 ◽  
Vol 31 (1-2) ◽  
pp. 41-48 ◽  
Author(s):  
A. Barletta ◽  
E. Zanchini
Keyword(s):  
Heat Flux ◽  
Forced Convection ◽  
Flux Distribution ◽  
Wall Heat Flux ◽  
Periodic Regime ◽  
Heat Flux Distribution ◽  
Laminar Forced Convection ◽  
Sinusoidal Wall

Experimental Estimate of the Continuous One-Dimensional Kernel Function in a Rectangular Duct With Forced Convection

2006 ◽  
Vol 128 (8) ◽  
pp. 811-818 ◽  
Author(s):  
Jinny Rhee ◽  
Robert J. Moffat
Keyword(s):  
Heat Flux ◽  
Forced Convection ◽  
Kernel Function ◽  
Flux Distribution ◽  
Constant Heat Flux ◽  
Kernel Functions ◽  
Rectangular Duct ◽  
Heat Flux Distribution ◽  
Constant Heat ◽  
One Dimensional

Abstract The continuous, one-dimensional kernel function in a rectangular duct subject to forced convection with air was experimentally estimated using liquid crystal thermography techniques. Analytical relationships between the kernel function for internal flow and the temperature distribution resulting from a known heat flux distribution were manipulated to accomplish this objective. The kernel function in the hydrodynamically fully developed region was found to be proportional to the streamwise temperature gradient resulting from a constant heat flux surface. In the hydrodynamic entry region of the rectangular duct, a model for the kernel function was proposed and used in its experimental determination. The kernel functions obtained by the present work were shown to be capable of predicting the highly nonuniform surface temperature rise above the inlet temperature resulting from an arbitrary heat flux distribution to within the experimental uncertainty. This is better than the prediction obtained using the analytically derived kernel function for turbulent flow between parallel plates, and the prediction obtained using the conventional heat transfer coefficient for constant heat flux boundary conditions. The latter prediction fails to capture both the quantitative and qualitative nature of the problem. The results of this work are relevant to applications involving the thermal management of nonuniform temperature surfaces subject to internal convection with air, such as board-level electronics cooling. Reynolds numbers in the turbulent and transition range were examined.

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