The hypersonic environment: Required operating conditions and design challenges

Wie, D. M. Van; Drewry, David; King, Don E.; Hudson, C. M.

doi:10.1023/b:jmsc.0000041688.68135.8b

Cited by 290 publications

(145 citation statements)

References 9 publications

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“…The combined aerodynamic and thermal loads present additional challenges which must be addressed during material selection [23]. A reusable TPS intended to have a multiple flight lifespan must resist high temperature creep.…”

Section: 1(d) Secondary Issuesmentioning

confidence: 99%

“…For both SiC and Si3N4, Vaughn and Maahs found the transition from passive oxidation protection to gaseous production of SiO (and mass loss) occurred at conditions of 1,347°C for an oxygen partial pressure of 2.5Pa and 1,543°C at 123.2Pa, indicating that increases in oxygen pressure elevated the maximum use temperature of the binary compounds [58]. Scramjet engines typically operate with dynamic pressures in the range of 24kPa to 96kPa [23]. The mole fraction of oxygen in air is 0.21 and stays relatively ________________________________________________________________________ constant with altitude.…”

Section: Figure 27 the Specific Yield Strength Of Some High Temperamentioning

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: 1(d) Secondary Issuesmentioning

confidence: 99%

Section: Figure 27 the Specific Yield Strength Of Some High Temperamentioning

confidence: 99%

Thermal Management at Hypersonic Leading Edges

Kasen

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“…hypersonic vehicle materials and structures must operate in this stressing aerothermal environment while being exposed to both oxidizing and reducing environments, and must at the same time be capable of surviving flight vibration, handling, and launch loads. 4 current approaches for building hypersonic engines use either ceramic matrix composites with oxidative coatings or fuel-cooled metallic walls. significant room for advancements lies in improved cycle life, weight reduction, sealing concepts, and diagnostics for these material systems.…”

Section: Developing Durable Enginesmentioning

confidence: 99%

Research of Solid Hydrocarbon Fuel Gasification Products Mixing with High-Enthalpy Gas Flux in Uniform Cross-Section Ducts

Fedotova¹,

Арефьев²,

Сухов³

2017

HoBMSTU.SME

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ypersonic airbreathing propulsion technology is rapidly maturing to enable flight vehicles with transformational capabilities. ApL has a rich history of leading-edge accomplishments in this arena. Laboratory-invented technology is being transitioned to a missile flight demonstration, and ApL is contributing to a variety of hypersonic technologies and vehicle system concepts being developed by the DoD. building from a substantial knowledge base on the operation of these emerging propulsion systems, this article discusses science and technology issues that will enable future performance improvements and expanded operational envelopes for these systems. critical technology challenges include improving our understanding of the stressing aerothermal environment, achieving the necessary component and integrated engine performance, dealing with the engine system dynamics to achieve robust operation, developing proper scaling laws to enable transition from ground test to flight systems, and developing advanced lightweight, hightemperature materials and cooling techniques to handle the engine environment. We also briefly address the potential warfighting payoff of systems that use high-speed missiles.

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“…To highlight the key flow characteristics near the blunted cowl-lip and subsequent effects, the external compression is simplified as a single oblique shock. The corresponding flow deflection angle, , is defined as 12.5, which is equal to the total turning angle of the three ramps [29]. Under the design conditions of Mach number of 6 and flight altitude of 26 km, the inlet with a theoretical sharp cowl-lip satisfies the following conditions: the external compression shock wave terminates with the apex of the sharp cowl-lip, and the cowl reflection shock is canceled at the ramp shoulder.…”

Section: Inlet Modelmentioning

confidence: 99%

Flow characteristics of hypersonic inlets with different cowl-lip blunting methods

Yue

Chang

2014

Sci. China Phys. Mech. Astron.

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Under hypersonic flight conditions, the sharp cowl-lip leading edges have to be blunted because of the severe aerodynamic heating. This paper proposes four cowl-lip blunting methods and studies the corresponding flow characteristics and performances of the generic hypersonic inlets by numerical simulation under the design conditions of a flight Mach number of 6 and an altitude of 26 km. The results show that the local shock interference patterns in the vicinity of the blunted cowl-lips have a substantial influence on the flow characteristics of the hypersonic inlets even though the blunting radius is very small, which contribute to a pronounced degradation of the inlet performance. The Equal Length blunting Manner (ELM) is the most optimal in that a nearly even reflection of the ramp shock produces an approximately straight and weak cowl reflection shock. The minimal total pressure loss, the lowest cowl drag, maximum mass-capture and the minimal aeroheating are achieved for the hypersonic inlet. For the other blunting manners, the ramp shock cannot reflect evenly and produces more curved cowl reflection shock. The Type V shock interference pattern occurs for the Cross Section Cutting blunting Manner (CSCM) and the strongest cowl reflection shock gives rise to the largest flow loss and drag. The cowl-lip blunted by the other two blunting manners is subjected to the shock interference pattern that transits with an increase in the blunting radius. Accordingly, the peak heat flux does not fall monotonously with the blunting radius increasing. Moreover, the cowl-lip surface suffers from severe aerothermal load when the shear layer or the supersonic jet impinges on the wall.

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The hypersonic environment: Required operating conditions and design challenges

Cited by 290 publications

References 9 publications

Thermal Management at Hypersonic Leading Edges

Thermal Management at Hypersonic Leading Edges

Research of Solid Hydrocarbon Fuel Gasification Products Mixing with High-Enthalpy Gas Flux in Uniform Cross-Section Ducts

Flow characteristics of hypersonic inlets with different cowl-lip blunting methods

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