Augmentation of heat transfer from a solid cylinder wrapped with a porous layer

Bhattacharyya, S.; Singh, Ashok

doi:10.1016/j.ijheatmasstransfer.2008.08.041

Cited by 37 publications

(15 citation statements)

References 15 publications

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“…Ithas been suggested to wrap the heat exchangertubes with aluminum foam instead of fin which has a positive effect on increasing the thermal efficiency due to its larger heat transfer area surface [10][11][12][13]. Bhattacharyya et al [10] studied different Reynolds number, Grashof number, permeability and thermal conductivity of the metal foam.…”

Section: Introductionmentioning

confidence: 99%

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Investigation of Coherence behind a Single Foamed Tube

Abdi¹,

Khashehchi²,

Hooman³

2017

FMRIJ

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In this paper the flow structures downstream of a foamed tube are compared to those of a bare tube with the same frontal areaand length. Experiments were conducted in a wind tunnel at Reynolds numbers 4000 and 16000. Particle image velocimetry (PIV) was used to obtain velocity vector field in two different perpendicular planes. To measure the effect of flow three-dimensionality, field of divergence on both planes was obtained and compared with each other. Moreover, to characterize the size of the flow structures downstream of the tube, for each of the aforementioned cases, two-point correlation functions were used as the statistical analysis tool. Analysis showed that, compared to the bare tube, the foamed one, in the X-Z plane (stream-wise, span-wise) increases the threedimensionality of the flow which is set forward in the perpendicular plane despite being less pronounced. Moreover, the structures downstream of a foamed tube are elongated in the stream-wise direction and are linearly independent of the inlet velocity, however, in span-wise and normal direction no significant change in the size of the structures between bare and foamed tube has been observed.

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Section: Introductionmentioning

confidence: 99%

“…Bhattacharyya et al [10] studied different Reynolds number, Grashof number, permeability and thermal conductivity of the metal foam. Their results show that a thin foam layer of high thermal conductivity increases the rate of heat transfer.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Coherence behind a Single Foamed Tube

Abdi¹,

Khashehchi²,

Hooman³

2017

FMRIJ

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“…As such, the air-side pressure drop [55,59,60], wake size [59,94] and vortex shedding [95] at different Reynolds numbers are investigated. Controlling the pressure drop is an important issue in heat exchangers, since the fan power that is required to pump the ambient air through the bundle is linearly proportional to the pressure drop.…”

Section: Introductionmentioning

confidence: 99%

“…Their results show the performance will improve when cylinder is covered by metal foam. The mixed convection is investigated by Bhattacharyya et al [60] for different Reynolds number, Grashof number, permeability and thermal conductivity of the porous material. They obtained the optimal thickness of the foam for heat transfer increase.…”

Section: Introductionmentioning

confidence: 99%

“…It has been suggested to wrap the heat exchanger tubes with aluminum foam instead of fin which has a positive effect on increasing the thermal efficiency due to its larger heat transfer area surface [55,60,61,63]. Bhattacharyya et al [60] 2005) showed that increasing the Reynolds number will increase the heat transfer up to a certain limit.…”

Section: Introductionmentioning

confidence: 99%

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Wake behind a rough (metal foam-covered) cylinder in cross-flow

Abdi¹

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The flow structures behind a circular cylinder are associated with various instabilities. These instabilities are characterized by the Reynolds number and they include the wake, separated shear layer and boundary layer. Depending on the physical application of the cylinder, increasing the level of turbulence by wrapping the cylinder with metal foam would be a target for drag reduction or heat transfer enhancement.In contrast to the extensive consideration that has been devoted to the flow around bare cylinders, the flow structures around the foam-covered cylinders and the characteristics of the wake behind such surfaces has received relatively little attention. Since the present study explores the possibility of using metal foams as replacements for fins on heat exchanger tubes, investigation on the flow-field structures downstream of a foam-covered cylinder and compare it to the bare cylinder specifies the feasibility of using the foamcovered cylinders in heat exchangers. Moreover, the outcome of this study can be used to develop an appropriate boundary condition for the porous-air interface modelling also increases the knowledge of turbulence in porous media.As it will be discussed more in detail in the following chapters, pressure drop and drag coefficient are directly linked to the wake and recirculation region, and to study these two phenomena, it is necessary to have in depth study on the flow-field down-stream of the cylinder. Hence, the purpose of this study is to investigate the wake region behind a foam- Moreover, using hot-wire anemometry, to investigate the energy of the flow inside and outside of the foam-covered cylinder's wake, let us know if a foam-covered cylinder can be treated as an obstacle to the incident flow with a rough surface or the whole foam can be considered as the combination of local jets that are coming out of the pores and disperse in random directions.III

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Forced convection mass deposition and heat transfer onto a cylinder sheathed by protective garments

et al. 2013

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In chemical, biological, radiological, and nuclear protective clothing, a layer of activated carbon material in between two textile layers provides protection against hazardous gases. A cylinder in cross flow, sheathed by such material, is generally used to experimentally test the garment properties. This is, however, complicated and predictive models are needed. We present a computational fluid dynamics model for the initial phase in which the carbon filter material is not yet saturated. The textiles are modeled as chemically inactive porous layers, the carbon filter particles have been resolved explicitly. The model has been validated against experimental data. We demonstrate that (1) computational fluid dynamics simulations can be used for the efficient design and optimization of protective garments, and (2) the addition of a highly porous active carbon layer highly increases the chemical protection capabilities, while having relatively little negative impact on the thermal comfort of protective garments.

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Augmentation of heat transfer from a solid cylinder wrapped with a porous layer

Cited by 37 publications

References 15 publications

Investigation of Coherence behind a Single Foamed Tube

Investigation of Coherence behind a Single Foamed Tube

Wake behind a rough (metal foam-covered) cylinder in cross-flow

Forced convection mass deposition and heat transfer onto a cylinder sheathed by protective garments

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