• Title, Summary, Keyword: Aluminum Foam

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Thermal Transport from an Aluminum Foam Heat Sink in a Confined Impinging Air Jet (국한 충돌공기제트에 의한 발포 알루미늄 방열기의 열전달 특성)

  • Hwang, Jun;Kim, Seo-Young;Kang, Byung-Ha
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.27 no.4
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    • pp.496-503
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    • 2003
  • An experimental study has been performed on thermal transport from an aluminum foam heat sink under a confined impinging air jet. Three kinds of aluminum foam heat sinks with 10, 20 and 40 PPI and a conventional pin-fin heat sink are tested in the present study. The jet Reynolds number is varied in the range of Re=667~5672 The effect of the confinement disk diameter and the distance between the confinement disk and the heater surface on the averaged Nusselt number is investigated in detail. The results are also compared with those of the unconfined impinging air jet. The critical distance, at which thermal performance shows a minimum compared to the unconfined jet impinging, will be described in terms of the Reynolds number and the pore density of the aluminum foam.

Pressure Loss and Enhancement of Heat Transfer in an Annulus Filled with Aluminum Foam

  • Noh, Joo-Suk;Han, Young-Hee;Lee, Kye-Bock;Lee, Chung-Gu
    • International Journal of Air-Conditioning and Refrigeration
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    • v.15 no.1
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    • pp.17-24
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    • 2007
  • An experimental investigation was carried out for 4 different types of the aluminum foam heat sinks which were inserted into the annulus. The purpose of this study is to examine the feasibility of a heat sink with high performance forced convective water cooling in the annulus. The local wall temperature distribution, inlet and outlet pressures and temperatures, and heat transfer coefficients were measured for heat flux of 13.6, 18.9, 25.1, 31.4 $kW/m^2$ and Reynolds number ranged from 120 to 9,000. Experimental results show that the departure from the Darcy's law is evident from the pressure loss and the friction factor is much higher while the significant enhancement in Nusselt number is obtained, and average Nusselt number of aluminum foam with high pore density is much higher than that of aluminum foam with low pore density. Correlations for the friction factor is proposed and used for design of thermal applications.

Heat Transfer from a Porous Heat Sink by Air Jet Impingement (충돌공기제트에서의 다공성 방열기의 열전달 특성)

  • 백진욱;김서영;강병하
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.13 no.2
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    • pp.73-79
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    • 2001
  • Experiment were carried out to investigate the heat transfer characteristics of an aluminum foam block as a porous heat sink on a heat source by a vertical air jet impingement that can be applied for electronics cooling. The performance of the aluminum foam heat sink was evaluated by the convective heat transfer coefficient on the heat source. At a fixed porosity, pore density ($\beta$) of the foam and Reynolds number Re were varied in the range of $\beta$a=10, 20, 40 PPI(Pore Per Inch) and $850\leqRe\leq25000$. A nozzle diameter and the nozzle-to-plate spacing were also varied. It was found that the convective heat transfer was enhanced by the aluminum foam heat sink with lower pore density due to relatively intensified flow through the foam block. The aluminum foam block with much reduced weight shows slightly better performance with larger Nusselt number, compared with the convectional heat sink.

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A study on Production of Al Foam by Using of Al Return Scrap for Sound and Vibration Absorption Materials

  • Hur, Bo-Young;Kim, Sang-Youl;Park, Dae-Chol;Jeon, Sung-Hwan;Park, Chan-Ho;Yoon, Ik-Sub
    • Proceedings of the IEEK Conference
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    • pp.198-201
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    • 2001
  • Porous structures of aluminum foam have been studied by using return aluminum scrap. The apparent foam shape, foam height, density, pore size and their distributions in various section areas of the experimental samples have been investigated. The sample have been cast into metallic mold, using aluminum foam prepared from a precursor based on pure Al ingot and return aluminum scrap mixed with various amounts of 1-2wt% increasing viscosity and foam agent materials. The process provides for flexibility in design of foam structures via relatively easy control over the amount of hydrogen evolution and the drainage processes which occur during foam formation. This is facilitated by manipulating parameters such as the foaming agent, thermal histories during solidification and mix melt viscosities. A metal for producing the foamed are decomposing a foaming agent in a molten metal such that there is an initial and a subsequent expansion due to foaming agent. It has been found that the Al porous foaming with variation amount of 1∼2wt% foam agent and at 2min holding time, which melting temperature has appeared homogeneous pore size at 650∼700$^{\circ}C$. The compression strength were 10-13 kg/min at 125ppi, and increased by higher pore density. The acoustical performance of the panel made with the foamed aluminum is considerably improved; its absorption coefficient shows NRC 0.6-0.8. It has been found that the Al foam is very preferable for the compactness of the thermal system.

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Mechanical Characteristics Analysis of Structural Light-weight Aluminum Foam (구조용 경량 알루미늄 발포금속의 기계적 특성 연구 분석)

  • Ma, Jeong Beom;Lee, Jeong Ick
    • Journal of the Korea Convergence Society
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    • v.2 no.3
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    • pp.1-6
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    • 2011
  • Aluminum foam is one of the representative light-weight materials. In this study we analyzed the mechanical properties of the aluminum foam structures. Aluminum materials with pores have novel mechanical characteristics such as flame retardancy, damping, and energy absorption which are superior to those of polymer foam. Furthermore its reusable properties draw considerable interests. General properties, energy and acoustic absorption will be investigated and future research issues such as binding techniques of foam materials with other structures will be discussed through foam application examples.

Manufacture and Bending Behavior of Stainless Steel Cylindrical Shell Filled with Aluminum Alloy Foam (다공성 알루미늄 합금이 충진된 스테인레스 강 원통 Shell의 제조 및 굽힘거동)

  • Kim, Am-Kee;Lee, Hyo-Jin;Cho, Seong-Seock
    • Proceedings of the KSME Conference
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    • pp.19-24
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    • 2003
  • Potential applications of foam-filled section are the automotive structures. A foam-filled section can be used for the front rail and firewall structures to absorb impact energy during frontal or side collision. In the case of side collision where bending is involved in the crushing mechanics, the foam filler will be significant in maintaining progressive crushing of the thin-walled structures so that more impact energy can be absorbed. In this study, the manufacturing process of closed cell aluminum alloy foam filled stainless steel tube was studied, and the various foam filled specimens including piecewise fillers were prepared, tested and discussed about the bending behaviors.

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Tensile Properties of Plate Attached Open Cell Aluminium Foams (판이 부착된 개포형 발포 알루미늄의 인장특성)

  • Kang, Bok-Hyun;Bu, Sung-Duk;Kim, Ki-Young
    • Journal of Korea Foundry Society
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    • v.27 no.2
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    • pp.83-87
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    • 2007
  • Aluminum plates of the same materials as the foam were attached by the casting process inserting the foam as a core to investigate the tensile property of open cell foams. Tensile properties of the open cell 6063 aluminum alloy foam of $10{\sim}30$ PPI were measured before and after heat treatment. Densities of test specimens were between 0.14 and $0.29g/cm^3$. Tensile strength of the 6063 aluminum foam after heat treatment showed little change. C values were in the range of $0.41{\sim}0.87$ for as cast foams and $0.11{\sim}0.27$ for T6 heat treated foams in the eq. of ${\sigma}^* _{pl}/{\sigma}_{ys}=C({\rho}/{\rho}_s)^{1.5}$, and increased with increase in the cell size.

Study on Compression Tests of Aluminum Foam and Honeycomb Sandwich Composites (알루미늄 폼 및 허니컴 샌드위치 복합재료의 압축실험에 관한 연구)

  • Bang, Seung-Ok;Kim, Key-Sun;Kim, Sei-Hwan;Song, Soo-Gu;Cho, Jae-Ung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.9
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    • pp.3802-3807
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    • 2011
  • In this study, in-plane and out-plane compression tests of aluminum foam and honeycomb sandwich composites were carried out. Through these tests, the relationships of load-displacements were analyzed and the compression characteristics were compared with each other. The specimens were compressed with the speed of 1mm/min by using the universal testing machine. Experimental procedures were taken with photograph by the camera and load cell data were stored into computer. Test results showed that buckling was occurred at the aluminum foam core and honeycomb core according to the increase of load. In the in-plane compression test, the maximum load of aluminum foam specimen was similar with that of honeycomb sandwich. The property of honeycomb was better than that of the foam in consideration of specific gravity. In the out-plane compression test, compression maximum load of aluminum honeycomb sandwich composite was higher than that of aluminum foam sandwich composite.

Simulation Analysis on the Compression Property of Sandwich Composite (샌드위치 복합재료의 압축 특성에 관한 시뮬레이션 해석)

  • Bang, Seung-Ok;Kook, Jeong-Han;Kim, Sei-Hwan;Cho, Jae-Ung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.2
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    • pp.478-484
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    • 2012
  • In this study, compression analyses of sandwich composites with porous core were carried out. Finite element models of aluminum foam and honeycomb core sandwich composite material were applied solid element. In the case of aluminum foam core, valid equivalence damage model was applied. In the in-plane compression analysis, the maximum load of aluminum foam core sandwich was similar with that of aluminum honeycomb core sandwich. But in case of aluminum honeycomb core sandwich, the load support region becomes longer in comparison with aluminum foam core sandwich. In the out-plane compression analysis, compression maximum load of aluminum honeycomb core sandwich was higher than that of aluminum foam core sandwich. Through these Simulation analysis, obtains the behavior of sandwich composites.

Bending Behaviors of Stainless Steel Tube Filled with Al5Si4Cu4Mg Closed Cell Aluminum Alloy Foam (발포 Al5Si4Cu4Mg 알루미늄 합금이 충진된 304 스테인리스강 원통의 굽힘저항 특성)

  • Kim, Am-Kee;Lee, Hyo-Jin;Cho, Seong-Seock
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.10
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    • pp.1686-1694
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    • 2003
  • The foam-filled tube beams can be used for the front rail and firewall structures to absorb impact energy during frontal or side collision of vehicles. In the case of side collision where bending is involved in the crushing mechanism, the foam filler would be effective in maintaining progressive crushing of the thin-walled structures so that much impact energy could be absorbed. In this study, bending behaviors of the closed-cell-aluminum-alloy-foam-filled stainless steel tube were investigated. The various foam-filled specimens including piecewise fillers were prepared and tested. The aluminum-alloy-foam filling offered the significant increase of bending resistance. Their suppression of the inward fold formation at the compression flange as well as the multiple propagating folds led to the increase of load carrying capacity of specimens. Moreover, the piecewise foams would provide the easier way to fill the thin-walled shell structures without the drawback of strength.