FREE MOLECULAR HEAT TRANSFER IN A RECTANGULAR CHANNEL AT HIGH SPEEDS

1986 ◽  
Author(s):  
A. Ansari ◽  
D. Widman
Keyword(s):  
Heat Transfer ◽  
Rectangular Channel ◽  
High Speeds

Enhancement of Heat Transfer in a Short Rectangular Channel with Substantial Deflection of Inlet Velocity from Axial Direction

2005 ◽  
Vol 36 (4) ◽  
pp. 311-318 ◽  
Author(s):  
R. Bunker ◽  
M. YA. Belen'kii ◽  
M. A. Gotovskii ◽  
B. S. Fokin ◽  
S. A. Isaev
Keyword(s):  
Heat Transfer ◽  
Rectangular Channel ◽  
Axial Direction ◽  
Enhancement Of Heat Transfer ◽  
Inlet Velocity

An Experimental and Numerical Study of Heat Transfer and Pressure Loss in a Rectangular Channel With V-Shaped Ribs

2006 ◽  
Author(s):  
Michael Maurer ◽  
Jens von Wolfersdorf ◽  
Michael Gritsch
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Thermal Performance ◽  
Pressure Loss ◽  
Numerical Study ◽  
Rectangular Channel ◽  
Reynolds Numbers ◽  
Transfer Enhancement ◽  
High Reynolds Numbers ◽  
High Reynolds

An experimental and numerical study was conducted to determine the thermal performance of V-shaped ribs in a rectangular channel with an aspect ratio of 2:1. Local heat transfer coefficients were measured using the steady state thermochromic liquid crystal technique. Periodic pressure losses were obtained with pressure taps along the smooth channel sidewall. Reynolds numbers from 95,000 to 500,000 were investigated with V-shaped ribs located on one side or on both sides of the test channel. The rib height-to-hydraulic diameter ratios (e/Dh) were 0.0625 and 0.02, and the rib pitch-to-height ratio (P/e) was 10. In addition, all test cases were investigated numerically. The commercial software FLUENT™ was used with a two-layer k-ε turbulence model. Numerically and experimentally obtained data were compared. It was determined that the heat transfer enhancement based on the heat transfer of a smooth wall levels off for Reynolds numbers over 200,000. The introduction of a second ribbed sidewall slightly increased the heat transfer enhancement whereas the pressure penalty was approximately doubled. Diminishing the rib height at high Reynolds numbers had the disadvantage of a slightly decreased heat transfer enhancement, but benefits in a significantly reduced pressure loss. At high Reynolds numbers small-scale ribs in a one-sided ribbed channel were shown to have the best thermal performance.

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