Experimental and numerical study of buoyancy-induced flow and heat transfer in an open annular cavity

1996 ◽  
Vol 39 (10) ◽  
pp. 2053-2066 ◽  
Author(s):  
Chetan P. Desai ◽  
Kambiz Vafai
Keyword(s):  
Heat Transfer ◽  
Numerical Study ◽  
Flow And Heat Transfer ◽  
Induced Flow ◽  
Buoyancy Induced Flow

Numerical Analysis of Buoyancy-Induced Flow and Heat Transfer in an Enclosure With Vents

2000 ◽  
Author(s):  
V. V. Calmidi ◽  
S. B. Sathe
Keyword(s):  
Heat Transfer ◽  
Printed Circuit Board ◽  
Numerical Study ◽  
Electronics Cooling ◽  
Circuit Board ◽  
Set Top Box ◽  
Flow And Heat Transfer ◽  
Quantitative Results ◽  
Induced Flow ◽  
Buoyancy Induced Flow

Abstract This paper reports a numerical study of buoyancy-induced flow and heat transfer in an enclosure with vents. The geometry closely resembles a “set-top-box” application frequently encountered in electronics cooling applications. The heat generating module is modeled as a planar heat source placed on a conducting printed circuit board (PCB). Full 3D and simplified 2D conjugate heat transfer models accounting for conduction and radiation in the solids and conduction and convection in the fluid were used Experiments performed to validate the 3D model have shown excellent comparisons with numerical results. A parametric study involving vent size, power dissipation, number of high conductivity power planes in the PCB has been performed with both the 3D and the 2D models. Although the quantitative results obtained from both types of analyses are similar only under certain conditions, qualitatively, the 2D analysis can be used to obtain useful insights into the complex overall transport mechanisms.

scholarly journals Buoyancy-Induced Flow and Heat Transfer in Compressor Rotors

2018 ◽  
Vol 140 (7) ◽  
Author(s):  
Hui Tang ◽  
Mark R. Puttock-Brown ◽  
J. Michael Owen
Keyword(s):  
Heat Transfer ◽  
Temperature Rise ◽  
Radial Growth ◽  
Radial Clearance ◽  
Rotating Disks ◽  
Compressor Blades ◽  
Nusselt Numbers ◽  
Flow And Heat Transfer ◽  
Induced Flow ◽  
Buoyancy Induced Flow

The buoyancy-induced flow and heat transfer inside the compressor rotors of gas-turbine engines affects the stresses and radial growth of the compressor disks, and it also causes a temperature rise in the axial throughflow of cooling air through the center of the disks. In turn, the radial growth of the disks affects the radial clearance between the rotating compressor blades and the surrounding stationary casing. The calculation of this clearance is extremely important, particularly in aeroengines where the increase in pressure ratios results in a decrease in the size of the blades. In this paper, a published theoretical model—based on buoyancy-induced laminar Ekman-layer flow on the rotating disks—is extended to include laminar free convection from the compressor shroud and forced convection between the bore of the disks and the axial throughflow. The predicted heat transfer from these three surfaces is then used to calculate the temperature rise of the throughflow. The predicted temperatures and Nusselt numbers are compared with measurements made in a multicavity compressor rig, and mainly good agreement is achieved for a range of Rossby, Reynolds, and Grashof numbers representative of those found in aeroengine compressors. Owing to compressibility effects in the fluid core between the disks—and as previously predicted—increasing rotational speed can result in an increase in the core temperature and a consequent decrease in the Nusselt numbers from the disks and shroud.

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