An Interferometric Study of Combined Free and Forced Convection in a Horizontal Isothermal Tube

Yousef, W. W.; Tarasuk, J. D.

doi:10.1115/1.3244449

Cited by 14 publications

(6 citation statements)

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“…This is because in the first part of the pipe, due to the effect of buoyancy the secondary flow gains momentum; but along the pipe, because of the heat balance between the fluid and wall, the buoyancy forces decrease gradually, resulting in the decrease of K. In general, the higher the Gr, the stronger the secondary flow and the sooner the maximum in K has been reached. Yousef and Tarasuk [13] in their experiment also found that there appeared a maximum value of the secondary flow near the entrance of the pipe. It can also be seen that, the smaller the inlet Reynolds number, the larger the relative magnitude of the secondary flow, and thus the larger value of K. What deserves attention is that it is for Re in = 1000 that the product f ⋅ Re has the largest value.…”

Section: Velocity and Temperature Profilesmentioning

confidence: 79%

Mixed convective heat transfer of water in a pipe under supercritical pressure

Guo

Bai

2005

Heat Trans. Asian Res.

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Because of the rapid properties variation of fluid under supercritical pressure, there is a violent secondary flow in a heated pipe, which will certainly complicate the heat transfer of fluid in a pipe under supercritical pressure. In this paper, a numerical study is conducted for the laminar developing mixed convective heat transfer of water under supercritical pressure. The velocity field and temperature field are given, and the influence of different parameters on flow and heat transfer is investigated in detail. The results show that secondary flow has a great influence on velocity and temperature distributions and thus affects the friction factor and the Nusselt number remarkably.

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Section: Velocity and Temperature Profilesmentioning

confidence: 79%

Mixed convective heat transfer of water in a pipe under supercritical pressure

Guo

Bai

2005

Heat Trans. Asian Res.

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“…Of course, in general, T(x,z * ) is not known and cannot be determined from a single interferogram. In several previous studies [60,61,62], the approach taken to overcome this difficulty has been to assume that f T is equal to the arithmetic mean fluid temperature, T . But, it is clear from eqn (50) that the effective fringe temperature f T is not the arithmetic average of T(x,z * ), integrated along the light beam.…”

Section: Beam-averaged Local Measurementsmentioning

confidence: 99%

Laser interferometry - Report #HT-01-2017

Naylor¹

2023

Preprint

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An introduction is given to the optical setup and principle of operation of classical and holographic interferometers that are used for convective he at transfer measurements. The equations for the evaluation of the temperature field are derived and methods of analysis are discussed for both two-dimensional and three-dimensional temperature fields. Emphasis is given to techniques for measuring local heat transfer rates. For two-dimensional fields, a method is presented for measuring the surface temperature gradient directly from a finite (wedge) fringe interferogram. This “direct gradient method” is shown to be most useful for the measurement of low convective heat transfer rates. For three-dimensional fields, the equations for calculating the beam-averaged local heat flux are presented. The measurement of the fluid temperature averaged along the light beam is shown to be approximate. However, an analysis is presented showing that for most cases the error associated with temperature variations in the light beam direction is small. Digital image analysis of interferograms to obtain fringe spacings is also discussed briefly.

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“…Experimental results are presented by Bergles & Simonds (1971) for the case of uniform wall flux boundary, by Yousef & Tarasuk (1981) for the case of uniform wall temperature boundary and by Osborne for the case of asymmetric heating. Early work revealed that the pressure-driven axial flow was superimposed with a secondary, buoyancy-driven flow consisting of two counter-rotating vortices.…”

Section: Introductionmentioning

confidence: 99%

Development of three-dimensional, streamwise-periodic flows in mixed-convection heat transfer

1993

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The three-dimensional, parabolized form of the coupled equations of motion and energy are solved to study the development of mixed-convection heat transfer in the entrance region of horizontal square ducts. The specific problem considered here is that of axially uniform heat flux and peripherally uniform temperature with parabolic inlet profile and uniform inlet temperature in a square cross-section. Previous studies have been confined mostly to two-dimensional flows in the fully developed region. Recent two-dimensional calculations have indicated the existence of multiple steady-state solutions in the fully developed region with two- and four-cell flow structure. Present three-dimensional calculations, carried over the whole entrance length and the full cross-section, indicate the evolutionary path that lead to such two-dimensional flows. Furthermore they shed new light on the nature of flows in regions where all known two-dimensional solutions become unstable in some manner. For low Grashof numbers and Pr = 0.73 the secondary velocities develop into an axially invariant state with two counter-rotating vortices. For Grashof numbers above 2.2 × 105 the inlet profiles evolve into a state with a four-cell secondary flow structure. As in a related problem of flow in a curved channel (Winters 1987; Bara et al. 1992), the two-dimensional, four-cell solutions are found to be unstable to asymmetric perturbations. Such perturbations trigger a new, streamwise-periodic mode which is sustained over long lengths in the flow direction. For Grashof numbers above 5.6 × 105 axially invariant two-cell solutions reappear. Some of the three-dimensional solutions corresponding to the streamwise periodic mode lack the reflective symmetry about the vertical centreline and hence these flows occur with multiplicity of two.

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An Interferometric Study of Combined Free and Forced Convection in a Horizontal Isothermal Tube

Cited by 14 publications

References 0 publications

Mixed convective heat transfer of water in a pipe under supercritical pressure

Mixed convective heat transfer of water in a pipe under supercritical pressure

Laser interferometry - Report #HT-01-2017

Development of three-dimensional, streamwise-periodic flows in mixed-convection heat transfer

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