Fabrication and testing of a leading-edge-shaped heat pipe

Glass, David E.; Camarda, Charles J.; Merrigan, Michael A.; Sena, J. Tom; Reid, Robert S.

doi:10.2514/6.1999-4866

Cited by 16 publications

(11 citation statements)

References 6 publications

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“…Firstly, fabrication issues with bending the tubes to a small leading edge radius (on the order of 3mm or less for scramjet inlets) is problematic [75]. At small radii, buckling of the wall at the bend line weakens the tube and pinches the vapor space closed, restricting flow.…”

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

confidence: 99%

“…Sodium was used as the working fluid. The half ________________________________________________________________________ -scale test model with an estimated 4 A slightly different approach has been taken by others, replacing the conventional tubes with an improved "D-shaped" cross-section [75], [76], radius on the order of 10cm was designed to sustain a cold wall heat flux of 40.8W/cm 2 and reduce wall temperatures at the tip from 1,317°C to 1,012°C. Radiant heat tests to simulate the high enthalpy Shuttle Orbiter reentry environment showed a temperature difference of only 5.6°C over the 56cm length [33], [34].…”

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

confidence: 99%

“…The concept of coupling heat pipes to leading edges has received only limited investigation [34], [35], [36], [75], [76]. Nearly all leading edge heat pipe concepts employed arrays of hollow circular tubes or channels either metallurgically joined to a high temperature skin or embedded in a wedge-shaped composite [33], [34], [35], [36].…”

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

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

confidence: 99%

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

confidence: 99%

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

confidence: 99%

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Thermal Management at Hypersonic Leading Edges

Kasen

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“…A single leading-edge-shaped heat pipe was later fabricated and tested. Figure 40 shows a heat pipe in the shape of a leading edge that was fabricated for an advanced space transportation system [9]. Figure 41 shows how this particular heat pipe would fit and be utilized on a leading edge.…”

Section: Nasp Heat-pipe-cooled Wing Leading Edgementioning

confidence: 99%

Ceramic Matrix Composite (CMC) Thermal Protection Systems (TPS) and Hot Structures for Hypersonic Vehicles

Glass

2008

15th AIAA International Space Planes and Hypersonic Systems and Technologies Conference

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140

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Thermal protection systems (TPS) and hot structures are required for a range of hypersonic vehicles ranging from ballistic reentry to hypersonic cruise vehicles, both within Earth's atmosphere and non-Earth atmospheres. The focus of this paper is on air breathing hypersonic vehicles in the Earth's atmosphere. This includes single-stage to orbit (SSTO), two-stage to orbit (TSTO) accelerators, access to space vehicles, and hypersonic cruise vehicles. This paper will start out with a brief discussion of aerodynamic heating and thermal management techniques to address the high heating, followed by an overview of TPS for rocket-launched and air-breathing vehicles. The argument is presented that as we move from rocket-based vehicles to air-breathing vehicles, we need to move away from the "insulated airplane" approach used on the Space Shuttle Orbiter to a wide range of TPS and hot structure approaches. The primary portion of the paper will discuss issues and design options for CMC TPS and hot structure components, including leading edges, acreage TPS, and control surfaces. The current state-of-the-art will be briefly discussed for some of the components. The two primary technical challenges impacting the use of CMC TPS and hot structures for hypersonic vehicles are environmental durability and fabrication, and will be discussed briefly.

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“…The fabrication and testing of leading edge shaped heat pipe were presented [19]. Reference [20] provided a feasibility study of metallic structural heat pipes as sharp leading edges for hypersonic vehicles and it was observed that the niobium alloy Ch-752 with lithium as the working fluid is an appropriate combination at Mach 6 -8 flight with a 3 mm leading edge radius.…”

Section: Introductionmentioning

confidence: 99%

Heat Pipe for Aerospace Applications—An Overview

Shukla¹

2015

JECTC

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The paper presents an overview of heat pipes, especially those used in different space missions. Historical perspectives, principles of operations, types of heat pipes are discussed. Several factors have contributed to the science and technology of the present state-of-Art heat pipe leading to the development of loop heat pipes, micro and miniature heat pipes and micro loop heat pipes. The paper highlights the advancement of heat pipe for hypersonic cruise vehicles, loop heat pipes with higher conductance in 10 K range, heat pipe switches for temperature control of the spacecraft electronics.

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Fabrication and testing of a leading-edge-shaped heat pipe

Abstract: A leading-edge-shaped heat pipe was successfully fabricated and tested.

Cited by 16 publications

References 6 publications

Thermal Management at Hypersonic Leading Edges

Thermal Management at Hypersonic Leading Edges

Ceramic Matrix Composite (CMC) Thermal Protection Systems (TPS) and Hot Structures for Hypersonic Vehicles

Heat Pipe for Aerospace Applications—An Overview

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