Heat transfer enhancement and drag by longitudinal vortex generators in channel flow

Fiebig, M.; Kallweit, Peter; Mitra, N. K.; Tiggelbeck, Stefan

doi:10.1016/0894-1777(91)90024-l

Cited by 205 publications

(66 citation statements)

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“…They found that the heat transfer was increased up to 60-degree angle of attack. The heat transfer enhancement per unit vortex generator area was the highest for delta wings followed by delta winglets and rectangular winglets [5]. However, the results from Ref.…”

Section: Introductioncontrasting

confidence: 51%

“…They found that the longitudinal vortex effects on the Stanton number were attributed largely to the distortion in the mean velocity field. Fiebig and his group [5][6][7][8] conducted systematic experimental investigations on heat transfer enhancement and induced drag using delta wings, rectangular wings, delta winglets and rectangular winglets in channel uniform flows. They found that the heat transfer was increased up to 60-degree angle of attack.…”

Section: Introductionmentioning

confidence: 99%

“…Extensive studies have been conducted on the heat transfer enhancement using turbulators in simulated heat exchangers, turbine blades and so on [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. The turbulator usually generates high turbulence vortical motion in uniform flows, which may change the mean velocity fields, modify the flow turbulence properties and the structures of the near wall layers in the velocity boundary layer.…”

Section: Introductionmentioning

confidence: 99%

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Flow structures and heat transfer characteristics in fan flows with and without delta-wing vortex generators

Chen

Shu

2004

Experimental Thermal and Fluid Science

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Effects of an external delta-wing vortex generator on the flow and heat transfer characteristics in fan flows and uniform flows were experimentally investigated and compared. A heated plate, installed on the bottom wall of a duct, was used as the heat transfer surface. Three-component mean and fluctuating velocity measurements were conducted using a laser Doppler velocimetry to characterize the flow structures and to obtain the near-wall flow parameters, including the axial mean velocity, axial vorticity and turbulent kinetic energy. Temperatures on the heat transfer surface were measured using thermocouples to obtain the Nusselt numbers. Results show that the external delta-wing vortex generator in fan flows has little overall effect on the near-wall averaged axial mean velocity and axial vorticity, but increases the turbulent kinetic energy, in the investigated X/D ranges. The increase in the turbulent kinetic energy by the delta-wing has little effect on heat transfer in the inherently vortical fan flows.Consequently, the delta-wing vortex generator in fan flows has little effect on the heat transfer augmentation.

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Section: Introductioncontrasting

confidence: 51%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Flow structures and heat transfer characteristics in fan flows with and without delta-wing vortex generators

Chen

Shu

2004

Experimental Thermal and Fluid Science

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“…They are utilized because they have great practical importance. Experimental investigations by Fiebig et al [14] revealed the enhancement of heat transfer in the presence of longitudinal vortices, which were triggered by vortex generators (VG). Liou et al [15] measured detailed local Nusselt number distributions with twelve differentshaped longitudinal VG.…”

Section: Introductionmentioning

confidence: 99%

Effect of Fluid Viscoelasticity on Turbulence and Large-Scale Vortices behind Wall-Mounted Plates

Tsukahara

Tanabe

Kawaguchi

2014

Advances in Mechanical Engineering

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Direct numerical simulations of turbulent viscoelastic fluid flows in a channel with wall-mounted plates were performed to investigate the influence of viscoelasticity on turbulent structures and the mean flow around the plate. The constitutive equation follows the Giesekus model, valid for polymer or surfactant solutions, which are generally capable of reducing the turbulent frictional drag in a smooth channel. We found that turbulent eddies just behind the plates in viscoelastic fluid decreased in number and in magnitude, but their size increased. Three pairs of organized longitudinal vortices were observed downstream of the plates in both Newtonian and viscoelastic fluids: two vortex pairs were behind the plates and the other one with the longest length was in a plate-free area. In the viscoelastic fluid, the latter vortex pair in the plate-free area was maintained and reached the downstream rib, but its swirling strength was weakened and the local skin-friction drag near the vortex was much weaker than those in the Newtonian flow. The mean flow and small spanwise eddies were influenced by the additional fluid force due to the viscoelasticity and, moreover, the spanwise component of the fluid elastic force may also play a role in the suppression of fluid vortical motions behind the plates.

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“…The latter study investigates enhancement in heat transfer from a fin tube heat exchanger with winglets by disrupting the growth of thermal boundary layer and reducing the minimum surface heat transfer in the wake region directly down stream of circular tubes. In channel flow without cylinder, many works have been published using vortex generator to enhance heat transfer [4][5][6] .…”

Section: Introductionmentioning

confidence: 99%

Effect of Winglet Shape on Heat Transfer from Heated Cylinder in Cross Flow

Jalil¹,

Abdulla²,

Yusuf³

2006

eng

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Abstract. Experimental investigation of the flow and heat transfer around a heated cylinder in cross flow with and without using winglets has been carried out. Distribution of the static pressure coefficients and Nusselt number and knowledge of the flow processes around the cylinder without winglets enable as to form an idea of the mechanism and pattern of the flow around the cylinder with winglets. There is also a slight increase in pressure drop.

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Heat transfer enhancement and drag by longitudinal vortex generators in channel flow

Cited by 205 publications

References 1 publication

Flow structures and heat transfer characteristics in fan flows with and without delta-wing vortex generators

Flow structures and heat transfer characteristics in fan flows with and without delta-wing vortex generators

Effect of Fluid Viscoelasticity on Turbulence and Large-Scale Vortices behind Wall-Mounted Plates

Effect of Winglet Shape on Heat Transfer from Heated Cylinder in Cross Flow

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