An Attempt to Experimentally Uncouple the Effect of Coriolis and Buoyancy Forces on Heat Transfer in Smooth Circular Tubes Which Rotate in the Orthogonal Mode

1991 ◽  
Author(s):  
W. D. Morris ◽  
R. Salemi
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Experimental Investigation ◽  
Forced Convection ◽  
Circular Tube ◽  
Leading Edge ◽  
Enhanced Heat Transfer ◽  
Coriolis Forces ◽  
Circular Tubes ◽  
Buoyancy Forces

This paper reports the results of an experimental investigation of the combined effect of Coriolis and buoyancy forces on forced convection in a circular tube which rotates about an axis orthogonal to its centre line. The experiment has been deliberately designed to minimise the effect of circumferential conduction in the tube walls by using material of relatively low thermal conductivity. A new correlating parameter for uncoupling the effect of Coriolis forces from centripetal buoyancy is proposed for the trailing and leading edges of the tube. It is demonstrated that enhanced heat transfer on the trailing edge occurs as a result of rotation. On the leading edge significant reductions in heat transfer compared to the zero rotation case can occur but with possible recovery at high rotational speeds.

An Attempt to Uncouple the Effect of Coriolis and Buoyancy Forces Experimentally on Heat Transfer in Smooth Circular Tubes That Rotate in the Orthogonal Mode

1992 ◽  
Vol 114 (4) ◽  
pp. 858-864 ◽  
Author(s):  
W. D. Morris ◽  
R. Salemi
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Experimental Investigation ◽  
Circular Tube ◽  
Leading Edge ◽  
Combined Effect ◽  
Enhanced Heat Transfer ◽  
Coriolis Forces ◽  
Circular Tubes ◽  
Buoyancy Forces

This paper reports the results of an experimental investigation of the combined effect of Coriolis and buoyancy forces enforced convection in a circular tube that rotates about an axis orthogonal to its centerline. The experiment has been deliberately designed to minimize the effect of circumferential conduction in the tube walls by using material of relatively low thermal conductivity. A new correlating parameter for uncoupling the effect of Coriolis forces from centripetal buoyancy is proposed for the trailing and leading edges of the tube. It is demonstrated that enhanced heat transfer on the trailing edge occurs as a result of rotation. On the leading edge significant reductions in heat transfer compared to the zero rotation case can occur, but with possible recovery at high rotational speeds.

Experimental Investigation of Heat Transfer in Coiled Annular Ducts

1988 ◽  
Vol 110 (2) ◽  
pp. 329-336 ◽  
Author(s):  
S. Garimella ◽  
D. E. Richards ◽  
R. N. Christensen
Keyword(s):  
Heat Transfer ◽  
Experimental Investigation ◽  
Circular Tube ◽  
Convection Heat Transfer ◽  
Convection Heat ◽  
Transfer Coefficients ◽  
Dean Number ◽  
Average Heat ◽  
Circular Tubes ◽  
Heat Transfer Coefficients

Forced convection heat transfer in coiled annular ducts was investigated experimentally. Average heat transfer coefficients were obtained for both laminar and transition flows. Two coiling diameters and two annulus radius ratios were used in the study. The data were correlated with Dean number and Reynolds number separately and compared with the available studies of coiled circular tubes and straight annular ducts. It was found that coiling augments the heat transfer coefficients above the values for a straight annulus especially in the laminar region. However, the augmentation is less than would be expected for a coiled circular tube. The augmentation decreases as the flow enters the transition region.

An Experimental Investigation of Heat Transfer and Buoyancy Induced Transition from Laminar Forced Convection to Turbulent Free Convection over a Horizontal Isothermally Heated Plate

1978 ◽  
Vol 100 (3) ◽  
pp. 429-434 ◽  
Author(s):  
H. Imura ◽  
R. R. Gilpin ◽  
K. C. Cheng
Keyword(s):  
Heat Transfer ◽  
Free Convection ◽  
Forced Convection ◽  
Leading Edge ◽  
Finite Amplitude ◽  
Heated Plate ◽  
Transfer Rates ◽  
Longitudinal Vortices ◽  
Turbulent Flow Regime ◽  
Laminar Forced Convection

The flow over a horizontal isothermally heated plate at Reynolds numbers below that at which hydrodynamic instabilities exist, is characterized by a region of laminar forced convection near the leading edge, followed by the onset of longitudinal vortices and their growth to a finite amplitude and finally a transition to a turbulent flow regime. Results are presented for the temperature profiles, the thermal boundary layer thickness, and the local Nusselt number. They are used to identify the various flow regimes. It was found that the transition from laminar forced convection to turbulent convection was characterized by the parameter Grx/Rex1.5 falling in the range 100 to 300. For values of this parameter greater than 300 the heat transfer rates were independent of Reynolds number and typical of those for turbulent free convection from a horizontal surface.

LES Simulations of Rotating Two-Pass Ribbed Duct With Coriolis and Centrifugal Buoyancy Forces at Re=100,000

2016 ◽  
Author(s):  
Cody Dowd ◽  
Danesh Tafti
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Large Eddy Simulations ◽  
The Other ◽  
Coriolis Forces ◽  
Flow And Heat Transfer ◽  
Large Eddy ◽  
Buoyancy Forces ◽  
First Pass ◽  
Duct Geometry

The focus of this research is to predict the flow and heat transfer in a rotating two-pass duct geometry with staggered ribs using Large-Eddy Simulations (LES). The geometry consists of a U-Bend with 17 ribs in each pass. The ribs are staggered with an e/Dh = 0.1 and P/e = 10. LES is performed at a Reynolds number of 100,000, a rotation number of 0.2 and buoyancy parameters (Bo) of 0.5 and 1.0. The effects of Coriolis forces and centrifugal buoyancy are isolated and studied individually. In all cases it is found that increasing Bo from 0.5 to 1.0 at Ro = 0.2 has little impact on heat transfer. It is found that in the first pass, the heat transfer is quite receptive to Coriolis forces which augment and attenuate heat transfer at the trailing and leading walls, respectively. Centrifugal buoyancy, on the other hand has a bigger effect in augmenting heat transfer at the trailing wall than in attenuating heat transfer at the leading wall. On contrary, it aids heat transfer in the second half of the first pass at the leading wall by energizing the flow near the wall. The heat transfer in the second pass is dominated by the highly turbulent flow exiting the bend. Coriolis forces have no impact on the augmentation of heat transfer on the leading wall till the second half of the passage whereas it attenuates heat transfer at the trailing wall as soon as the flow exits the bend. Contrary to phenomenological arguments, inclusion of centrifugal buoyancy augments heat transfer over Coriolis forces alone on both the leading and trailing walls of the second pass.

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