Combined forced-free laminar heat transfer to a highly heated gas in a vertical annulus

Hashimoto, Kazuo; Akino, Norio; Kawamura, Hiroshi

doi:10.1016/0017-9310(86)90042-6

Cited by 13 publications

(6 citation statements)

References 7 publications

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“…Many studies of mixed convection in vertical slots and annuli have adopted the parallel flow assumptions (Shumway and McEligot, 1971;El-Shaarawl and Sarhan, 1980;Kim, 1985;Hashimoto, Akino and Kawamura, 1986;Quintiere and Mueller, 1973;Habchi and Acharya, 1986;, and ignored the possible hydrodynamic instabilities that can lead to increased mixing of the fluid. Thus, the results obtained without accounting for these effects will tend to underpredict the actual heat transfer rates.…”

Section: Introductionmentioning

confidence: 99%

Mixed Convection in an Annulus of Large Aspect Ratio

Yao

Rogers

1989

Journal of Heat Transfer

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ixed Convection in an Annulus of Large Aspect Ratio Mixed convection in an annulus of large aspect ratio is studied. At an aspect ratio of 100, the effect of wall curvature is minimal, and both the base flow and the stability characteristics approach those of a two-dimensional channel flow. The linearstability results demonstrate that the fully developed flow is unstable in regions of practical interest in an appropriate parameter space. Consequently, commonly assumed steady parallel countercurrent flows in many idealized numerical and analytical studies are unlikely to be observed experimentally.

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Section: Introductionmentioning

confidence: 99%

Mixed Convection in an Annulus of Large Aspect Ratio

Yao

Rogers

1989

Journal of Heat Transfer

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“…The average values of the other parameters can be calculated based on calculation of average cylinder surface temperature and average bulk air temperature as follows: ( ) The variation of inner surface temperature of the outer cylinder along the axial distance for the same heat flux and Reynolds number, and for different Taylor number and exciting frequencies is plotted, for the selected runs, in Figs. (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15). In general, these figures show that the inner surface temperature of the outer cylinder decreases along the length of the cylinder with different values of frequencies if Reynolds number is kept constant, when the outer cylinder is under forced vibration in comparison to that without vibration.…”

Section: Discussionmentioning

confidence: 99%

“…The effect of vibration on the surface cylinder temperature variation for q=468 W/m 2 and Reynolds numbers (514, 931, 1316, 1509 & 1991) and Taylor number (10.44x10 4 & 8223x10 4 ) is shown in Figs. (2)(3)(4)(5), respectively. These figures reveal a decreasing in surface temperature along the length of the cylinder as the annulus vibrated by the excitation frequency (32 & 77) Hz.…”

Section: Discussionmentioning

confidence: 99%

“…It depends on both the amplitude (A) and frequency (Fr) and the product of these two parameters. The applications include rotating electric motor, chemical mixing process, swirl nozzles, combustion chambers, fiber coating applications and drying machinery, gas or oil exploration drills, journal bearing, rotating heat exchangers, atmospheric circulation, cooling of rotor blades of gas-turbines, ramjets attached to the rotors of helicopters and rotating condensers for sea water distillation [2].…”

Section: Introductionmentioning

confidence: 99%

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Effect of Vibration on the Heat Transfer Process in the Developing Region of Annulus with Rotating Inner Cylinder

A. Tawfik,

A. Mohammed,

Zuhair Zain

2015

ETJ

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Experimental investigation has been carried out to study the effect of induced vibration of a simply supported on the heat transfer process in the simultaneously developing of hydrodynamic and thermal boundary layer region of a concentric vertical annulus with uniformly heated outer cylinder and rotating solid inner cylinder. The experimental setup consists of an annulus which has a radius ratio of 0.365 and outer cylinder with a heated length 1.2 m subjected to the constant heat flux. The investigation covers Reynolds number (Re) range from 514 to 1991, Taylor number (Ta) values are 10.44×10 4 & 82.23×10 4 , heat flux varied from 468 W/m 2 to 920 W/m 2 and frequency (Fr) values are 32 & 77 Hz. Results showed for all frequency values which that the local Nusselt number values increase as the heat flux increases when the value of frequency near the natural frequency and the value of surface radiation decrease. Correlation equations have been deduced to calculate the rate of heat transfer, represented by the average Nusselt number (Nu m ) as a function of (Ta), (Ra) and (Fr). A comparison has been made between the present work and the previous works for temperature and local Nusselt number variations and it has given a good agreement.

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“…The majority of this work has been restricted to the axially symmetric flow in the annulus, see for example E1-Shaarawi et al [1] and Hashimito et al [2], who solved parabolic systems of equations by marching from the entrance of the annulus to either the region of fully developed flow or to the onset of flow reversal. However, studies concerning the isothermal flow in the eccentric annulus have shown that the degree of offset of the axes of the two cylinders greatly affects the flow, see for example Snyder and Goldstein [3] who provide an analysis of the fully developed velocity distribution.…”

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confidence: 99%

Developing combined convection of non-Newtonian fluids in an eccentric annulus

Ingham

Patel

1997

Acta Mechanica

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Summary. Laminar combined convection of non-Newtonian fluids in vertical eccentric annuli, in which the inner and outer walls are held at different constant temperatures is considered and a new economical method of solution for the three-dimensional flow in the annulus is developed. Assuming that the ratio of the radial to the vertical scale, e, is small, as occurs frequently in many industrial applications, then the governing equations can be simplified by expanding all the variables in terms of e. This simplification gives rise to the presence of a dominant cross-stream plane in which all the physical quantities change more rapidly than in the vertical direction. The solution trechnique consists of marching in the vertical streamwise direction using a finite-difference scheme and solving the resulting equations at each streamwise step by a novel technique incorporating the Finite Element Method. The process is continued until the velocity, pressure and temperature fields are fully developed, and results are presented for a range of the governing non-dimensional parameters, namely the Grashof, Prandtl, Reynolds and Bingham numbers.

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Combined forced-free laminar heat transfer to a highly heated gas in a vertical annulus

Cited by 13 publications

References 7 publications

Mixed Convection in an Annulus of Large Aspect Ratio

Mixed Convection in an Annulus of Large Aspect Ratio

Effect of Vibration on the Heat Transfer Process in the Developing Region of Annulus with Rotating Inner Cylinder

Developing combined convection of non-Newtonian fluids in an eccentric annulus

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