Hydrodynamics and Heat Transfer in Heat Exchanger Channels With Spherical Holes

Leontiev, A. I.; Попов, И. А.; Gortyshov, Yu. F.; Olympiev, V. V.; Щелчков, А. В.; Каськов, С.И.

doi:10.1115/imece2006-13552

Cited by 5 publications

(5 citation statements)

References 11 publications

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“…Unfortunately, the increase of heat transfer is a companied by an increase in pressure drop [21] resulting in a performance factor increase of 33% in the vicinity of the protrusion. Once again there appears to be contradiction with the work of Leontiev et al [16] who indicate in their (Figure 1) that the performance factor is decreased when a protrusion is introduced in the channel. Similarly to the case of the dimple mentioned above, the reasons for this difference have not been established.…”

Section: Single Protrusioncontrasting

confidence: 75%

“…Leontiev and his co-workers [16,17] claimed that heat transfer is significantly increased with dimples in a channel in the same Reynolds number range as that studied by Alshroof et al [13]. They also found that dimples increases the pressure drop.…”

Section: Introductionmentioning

confidence: 86%

“…Similarly, Leontiev et al [16] studied the flow and heat transfer in channels with spherical dimples and proposed 'models' of flow separation in the laminar regime which were functions of the dimple parameters and Re h , the Reynolds number based on the dimple depth. As Re h is increased, the flow appears to separate with the formation of the symmetric vortices about the central axial plane of the dimple.…”

Section: Introductionmentioning

confidence: 99%

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Flow Structure and Heat Transfer Enhancement in Laminar Flow With Protrusion-Dimple Combinations in a Shallow Rectangular Channel

Alshroof

Reizes

Timchenko

et al. 2009

Volume 2: Theory and Fundamental Research; Aerospace Heat Transfer; Gas Turbine Heat Transfer; Computational Heat Transfer

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The effect of introducing combinations of spherical dimples and protrusions in a shallow rectangular channel on the flow and heat transfer in the laminar regime has been studied numerically. Four different cases were investigated. These consisted of: an isolated dimple, an isolated protrusion both placed on the centerline of one of the wide face of the channel, a combination of a dimple located on the centerline of the wide face of the channel and a protrusion located downstream but shifted to the side, and finally, a combination in which the protrusion and the dimple are reversed. The resultant, very complex flow structure and thermal fields in the channel are presented. The introduction of a single dimple results in a small enhancement of heat transfer and a very small reduction in pressure drop relative to those obtained in a smooth channel. However, a significant enhancement in heat transfer obtained from a single protrusion is associated with marginal increase in pressure drop. The addition of a protrusion downstream of the dimple leads to an increase of 30% in heat transfer augmentation above that which pertains for the isolated protrusion without any increase in the pressure drop. With the reversal of the positions of the protrusion and the dimple no effect on either the pressure drop or the heat transfer has been observed.

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Section: Single Protrusioncontrasting

confidence: 75%

Section: Introductionmentioning

confidence: 86%

Section: Introductionmentioning

confidence: 99%

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Flow Structure and Heat Transfer Enhancement in Laminar Flow With Protrusion-Dimple Combinations in a Shallow Rectangular Channel

Alshroof

Reizes

Timchenko

et al. 2009

Volume 2: Theory and Fundamental Research; Aerospace Heat Transfer; Gas Turbine Heat Transfer; Computational Heat Transfer

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“…Structured surface elements -vortex generators of different forms which are applied on heat-exchange surfaces -are promising means for heat transfer intensification in cooling systems of radioelectronic and power equipment and in channels of various power-generating equipment and transportation facilities [11][12][13]. This type of heat transfer intensifiers destroys the laminar boundary layer or the viscous sublayer of the turbulent boundary layer without affecting the main flow and ensures a high thermal and thermohydraulic efficiency [14,15]. The flow past dimples of variable depth under different flow conditions has special features due to the fact that tornado-like vortex structures have two orientations of their axes at the exit from the surface dimple: to the left or to the right, or they are in the stage of change of orientation.…”

Section: Reviewmentioning

confidence: 99%

Calculation and Experimental Study of Heat Exchange in a System of Plane-Parallel Channels with Surface Intensifiers

Каськов¹

2021

Nelin. Dinam.

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This paper presents the results of numerical investigation, calculation analysis and experimental study of heat exchange in a system of plane-parallel channels formed by rectangular fins, which are applied in a heat removal device using heat tubes for power semiconductor energy converters. Passive cooling (heat removal by radiation and natural convection) and active cooling (heat removal by radiation and forced convection) are investigated for various velocities of air cooling of fins by spherical vortex generators applied to its surface. A comparative analysis of the results is carried out for the average effective heat removal resistance and for the average temperature at the ends of the fins. The application of numerical modeling to solve such problems confirms the effectiveness of computational technologies. The difference between the results of the study ranges from 10 to 16% depending on the airflow rate.

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“…Similarly, Leontiev et al [2006] studied the flow and heat transfer in channels with spherical dimples and proposed 'models' of flow separation in the laminar regime which were functions of the dimple parameters and Re h , the Reynolds number based on the dimple depth. As Re h is increased, the flow appears to separate with the formation of the symmetric vortices about the central axial plane of the dimple.…”

Section: Introductionmentioning

confidence: 99%

Heat Transfer Enhancement in Laminar Flow by a Protrusion in a Rectangular Channel

Alshroof

Reizes

2008

International Symposium on Advances in Computational Heat Transfer

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A numerical investigation has been performed to determine the effect on heat transfer in the laminar regime of introducing a single protrusion in a rectangular channel. The geometry consists of a three dimensional channel 10 mm high, 40 mm wide and 290 mm long in which a spherical protrusion was placed 90 mm from the inlet on the centreline of one of the wide sides. The print diameter of the obstacle was equal to the height of the channel and it protruded 2.2 mm above the surfaces. In order to properly take into account developing flow, a 30 mm region was introduced upstream of the inlet. Adiabatic wall with zero shear stress boundary conditions were used on all four walls of this region and uniform velocity and temperature distributions were assumed at the inlet of the calculation region. The two wide plates of the channel and the protrusion were set to 45ºC and the other two sides adiabatic. The fluid was assumed to be silicon oil with an inlet velocity of 1 ms-1 at a temperature of 20ºC, yielding a Reynolds number of 1600 based on the hydraulic diameter of the channel. A commercial code, ANSYS-CFX11.0 was used for all simulations. The resultant very complex flow and thermal fields in the channel are discussed in detail. The presence of the protrusion results in an enhancement in the total heat transfer rate of 7% above that of a channel lined with flat plates only. This is a worthwhile increase since it is brought about by a pressure increase of only 1%. NOMENCLATURE x coordinate in the direction parallel to channel walls y coordinate in the direction perpendicular to the bottom wall. z coordinate in the direction perpendicular to the side wall.

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Hydrodynamics and Heat Transfer in Heat Exchanger Channels With Spherical Holes

Cited by 5 publications

References 11 publications

Flow Structure and Heat Transfer Enhancement in Laminar Flow With Protrusion-Dimple Combinations in a Shallow Rectangular Channel

Flow Structure and Heat Transfer Enhancement in Laminar Flow With Protrusion-Dimple Combinations in a Shallow Rectangular Channel

Calculation and Experimental Study of Heat Exchange in a System of Plane-Parallel Channels with Surface Intensifiers

Heat Transfer Enhancement in Laminar Flow by a Protrusion in a Rectangular Channel

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