Turbulent natural convection flow in a vertical channel with anti-symmetric heating

Ayinde, T.; Said, S.A.M.; Habib, Mohamed A.

doi:10.1007/s00231-007-0359-z

Cited by 18 publications

(6 citation statements)

References 19 publications

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“…The flow pattern of the entire channel in this case is similar to air flow in a tall enclosure (i.e. A > 20) as presented by Wright et al (2006) and it is consistent with the velocity field observations made by Ayinde et al (2008). There is a close agreement of the streamlines between the experimental flow visualization and the numerical solution, which is shown in Figure 5.2(c).…”

Section: Preliminary Flow Visualization Resultssupporting

confidence: 87%

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Experimental and Numerical Study of Free Convection in a Vertical Channel with Opposing Buoyancy Forces

Roeleveld¹

2021

Preprint

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Free convective heat transfer inside a vertical channel was studied both experimentally and numerically. An experimental model of an isothermally, asymmetrically heated vertical channel was constructed to study various cases of opposing buoyancy forces. Many studies in the literature have investigated buoyancy forces in a single direction. The study presented here investigated opposing buoyancy forces, where one wall is warmer than the ambient and the other wall is cooler than the ambient. Five different temperature ratios were studied using four different channel spacings between the two channel walls. A Mach-Zehnder interferometer provided temperature field visualization. In addition, local and average heat transfer measurements were made with the interferometer. Flow visualization was conducted to determine the flow pattern inside the channel. The measured local and average Nusselt number data were compared to numerical solutions obtained using ANSYS FLUENT. A steady laminar model and a steady k-ε turbulence model with two different wall functions were used. Numerical solutions were obtained for a Prandtl number of 0.71 and Rayleigh numbers ranging from the laminar fully developed flow regime to the turbulent isolated boundary layer regime.

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Section: Preliminary Flow Visualization Resultssupporting

confidence: 87%

“…Two aspect ratios of 6.25 and 12.5 and two temperature differences of T H -T C = 15 and 30 ºC were used to investigate turbulent flow in the anti-symmetrical (R T = −1) heating of a vertical channel by Ayinde et al (2008). These conditions gave Rayleigh numbers of 1.0 × 10 5 to 1.6 × 10 6 .…”

Section: Opposing Buoyancy Forces Inside a Heated Vertical Channelmentioning

confidence: 99%

Experimental and Numerical Study of Free Convection in a Vertical Channel with Opposing Buoyancy Forces

Roeleveld¹

2021

Preprint

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“…Ayinde et al [12] also investigated turbulent fiow in an antisymmetrically heated vertical channel. Two temperature differences of TH -Tc= 15 °C and 30 °C were used between the two channel walls.…”

Section: (7)mentioning

confidence: 97%

“…(9) and (11), respectively. Using the temperature gradient, the local heat fluxes on the cold and hot walls of the channel were calculated using dT and = k. dT (12) where k^ is the thermal conductivity of the air at the surface temperature. The hot wall heat flux is always positive and the cold wall heat flux is typically negative in this study.…”

Section: Laser Interferometiy a 200 MM Diameter Beam Machzehndermentioning

confidence: 99%

Free Convection in Asymmetrically Heated Vertical Channels With Opposing Buoyancy Forces

Roeleveld

Naylor

Leong

2014

Journal of Heat Transfer

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Laser interferometry and flow visualization were used to study free convective heat transfer inside a vertical channel. Most studies in the literature have investigated buoyancy forces in a single direction. The study presented here investigated opposing buoyancy forces, where one wall is warmer than the ambient and the other wall is cooler than the ambient. An experimental model of an isothermally, asymmetrically heated vertical channel was constructed. Intetferometry provided temperature field visualization and flow visualization was used to obtain the streamlines. Experiments were carried out over a range of aspect ratios berween 8.8 and 26.4, using temperature ratios of 0, -0.5, and -0.75. These conditions provide a modified Rayleigh number range of approximately 5 to 1100. In addition, the measured local and average Nusselt number data were compared to numerical solutions obtained using ANSYS FLUENT. Air was the fluid of interest. So the Prandtl number was fixed at 0.71. Numerical solutions were obtained for modified Rayleigh numbers ranging from the laminar fully developed flow regime to the turbulent isolated boundary layer regime. A semi-empirical correlation of the average Nusselt number was developed based on the experimental data.

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“…Therefore it is required to solve a problem of an air cavity dimension (width) which ensures a maximum airflow rate letting in. A number of researchers have made attempts to describe airflow movement in a ventilated cavity [5][6][7][8][9][10][11][12][13][14][15][16][17][18]. But a successive area focus development is subject to a more accurate calculation and determination in regard of a multi-purpose methodology to calculate hydraulic parameters of airflow in air cavity [5][6][7][8][9][10][11][12][13][14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Diffused Structure of Drained and Back-Ventilated Rainscreen Claddings

Petrochenko

Yavtushenko

2014

AMR

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The major problem in ventilation systems designing is an empiric range of parameters of an air cavity and rustics between cladding panels which results in unventilated layers emergence. Whereas insufficient air interchange causes icing of as substructure elements which come out into a ventilated air cavity as facing outer layer in winter period, and reducing of heat-protective properties of the structure in whole. The aim of this survey is to elaborate the methods meant for calculating the parameters of hydraulic airflow in a ventilated air cavity which allow determining rational and optimal dimensions of hydraulically optimal air cavity in rainscreens of buildings and other constructions. As an outcome it has been specified that it is necessary to design a ventilated rainscreen cladding with a ventilated air cavity expanding from bottom to top with the purpose to reduce the losses.

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Turbulent natural convection flow in a vertical channel with anti-symmetric heating

Cited by 18 publications

References 19 publications

Experimental and Numerical Study of Free Convection in a Vertical Channel with Opposing Buoyancy Forces

Experimental and Numerical Study of Free Convection in a Vertical Channel with Opposing Buoyancy Forces

Free Convection in Asymmetrically Heated Vertical Channels With Opposing Buoyancy Forces

Diffused Structure of Drained and Back-Ventilated Rainscreen Claddings

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