A multifunctional heat pipe sandwich panel structure

Queheillalt, Douglas T.; Carbajal, Gerardo; Peterson, G. P.; Wadley, H.N.G.

doi:10.1016/j.ijheatmasstransfer.2007.03.051

Cited by 77 publications

(44 citation statements)

References 34 publications

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“…To fit within the curvature of the tip, the foam was 206 ________________________________________________________________________ compressed in the normal direction to �� = 0.71mm using platens fixtured in a press brake. Queheillalt et al [84] showed via scanning electron micrographs and the rising meniscus experimental method that the compression ratio (compressed thickness to uncompressed thickness) of the open cell nickel foam closely follows the constriction ratio (compressed pore diameter to uncompressed pore diameter) of the effective pore diameter.…”

Section: Discussionmentioning

confidence: 99%

“…The honeycomb core was perforated to allow vapor cross-flow between cells and notched at the base of its walls for fluid return. Queheillalt et al designed and tested a nickel-plated aluminum flat heat plate having a truncated square honeycomb core, which allowed three dimensional vapor flow [84]. A nickel foam was used for the wick and deionized water for the working fluid.…”

Section: Figure 211 Cross-section Schematic Of a Cylindrical Heat Pmentioning

confidence: 99%

“…The benefit of cellular materials which offer low resistance pathways for easy vapor flow while providing structural load support in two-phase heat spreaders has been described [84], [128]. In view of the discussion on the capillary limit (Chapter 4), a core design with low vapor drag allows the latent heat to be transported through the core with little resistance.…”

Section: Leading Edge Design and Fabricationmentioning

confidence: 99%

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Thermal Management at Hypersonic Leading Edges

Kasen

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The intense heat flux incident upon the leading edges of hypersonic vehicles traveling through the low earth atmosphere at speeds of Mach 5 and above requires creative thermal management strategies to prevent damage to leading edge components. Conventional thermal protection systems (TPSs) include the ablative coatings of NASA's Mercury, Gemini, and Apollo vehicles and the reusable reinforced carbon-carbon (RCC) system of the Space Shuttle Orbiter. The ablative approach absorbs heat by endothermic transformation (phase and/or chemical change to the polymeric coating). The heat is dissipated from the vehicle as the single-use coating eventually vaporizes. The RCC approach manages the intense heat by operating at high temperatures and radiating heat to its surroundings. The effectiveness of both approaches is predicated on keeping the heat flux that impinges upon the susceptible aluminum airframe below a critical level.ii ________________________________________________________________________ This dissertation has explored an alternative metallic TPS concept which seeks to redistribute the heat from the leading edge, thereby eliminating local hot spots. It makes use of high thermal conductance heat pipes coupled to the leading edge so that the thermal load may be redistributed from a high heat flux location (at the stagnation point) to regions where it can be effectively radiated from the vehicle. The sealed system concept is based upon the evaporation of a fluid near the heat source that sets up a region of elevated vapor pressure inside the pipe. The latent heat is transported down the resulting pressure gradient by the vapor stream where it condenses at cooler regions, releasing the heat for removal.Replenishment of the condensed working fluid to the evaporator region is accomplished through the capillary pumping action of a porous wick which lines the interior surface of the pipe.A design methodology for a wedge-shaped heat pipe is presented which uses a coupled flow-wall temperature model to construct design maps which relate design parameters of the leading edge system (overall length, wall thickness, and alloy) to its operating conditions (isothermal temperature, maximum temperature, maximum thermal stress). Potential bounds on heat transport due to physical phenomena linked to the sound speed within a chamber (sonic limit), capillarity, and boiling nucleation are considered by extending models developed for tube designs to the wedge geometry. A new heat flux limit is proposed which, should it be exceeded, subjects the leading edge to thermally-induced plastic deformation of the TPS. iii ________________________________________________________________________To investigate the validity of the design approach and thermal spreading effectiveness of the proposed concept, a low temperature wedge-shaped leading edge was designed and constructed using stainless steel as the case material and water as the working fluid. Under localized tip heating, the maximum temperatures were significantly reduced compa...

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Section: Discussionmentioning

confidence: 99%

Section: Figure 211 Cross-section Schematic Of a Cylindrical Heat Pmentioning

confidence: 99%

Section: Leading Edge Design and Fabricationmentioning

confidence: 99%

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Thermal Management at Hypersonic Leading Edges

Kasen

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“…[39][40][41] With the development of alternative processes to CVD on a polymer template, these and other applications may also benefit from the porous structure. Electrodeposition, for example, has unique capabilities for nanoscale control.…”

Section: Discussionmentioning

confidence: 99%

Solid State Foaming of Nickel, Monel, and Copper by the Reduction and Expansion of NiO and CuO Dispersions

et al. 2018

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Nickel and its alloys are useful in a range of applications, and nickel foams have increased in popularity for functional applications, such as electrodes. Despite their versatility and interest for burgeoning technologies, there is only one well-developed method for producing porous nickel commercially. This work introduces a simple method for creating porosity in nickel and Monel (70% Ni, 30% Cu) that results in sub-micron to micron-scale pores and grains. This is accomplished by creating oxide dispersions in the metallic matrix and then reducing those oxides at elevated temperature to form pores. It is found that nickel and Monel reach maximum porosity at 800 C withMonel reaching a higher overall porosity (33% vs. 25% for Ni), whereas Cu exhibited 40% porosity under the same conditions. Varied matrix and oxide pairings are examined microstructurally, and the effects of matrix strength, oxide chemistry, and other factors are considered to determine factors in pore development. Uniquely, this method produces pores within individual metallic particles, so this porosity can be added to other powder methods of solid state foaming to enhance the performance in functional applications.

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“…Wicks can be made of compressed nickel foam, and the development and testing of such wicks were reported in an earlier paper [12]. This type of wick has the advantage that the wick properties can be selected within a wide range by choosing the degree of compression [13].…”

Section: Introductionmentioning

confidence: 99%

Analysis of a Vertical Flat Heat Pipe Using Potassium Working Fluid and a Wick of Compressed Nickel Foam

2016

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Heat at high temperatures, in this work 400-650˝C, can be recovered by use of cooling panels/heat pipes in the walls of aluminum electrolysis cells. For this application a flat vertical heat pipe for heat transfer from a unilateral heat source was analyzed theoretically and in the laboratory, with special emphasis on the performance of the wick. In this heat pipe a wick of compressed nickel foam covered only the evaporator surface, and potassium was used as the working fluid. The magnitudes of key thermal resistances were estimated analytically and compared. Operating temperatures and wick performance limits obtained experimentally were compared to predictions. Thermal deformation due to unilateral heat flux was analyzed by the use of COMSOL Multiphysics ® . The consequences of hot spots at different locations on the wick were analyzed by use of a numerical 2D model. A vertical rectangular wick was shown to be most vulnerable to hot spots at the upper corners.

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A multifunctional heat pipe sandwich panel structure

Cited by 77 publications

References 34 publications

Thermal Management at Hypersonic Leading Edges

Thermal Management at Hypersonic Leading Edges

Solid State Foaming of Nickel, Monel, and Copper by the Reduction and Expansion of NiO and CuO Dispersions

Analysis of a Vertical Flat Heat Pipe Using Potassium Working Fluid and a Wick of Compressed Nickel Foam

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