Search Results

Numerical simulations of hypersonic flow around a 2-D cylinder and a 3-D complete reentry vehicle have been carried out by solving Euler/Navier-Stokes equations which incorporate the equation of state for an equilibrium gas. ...The results of hypersonic flow analysis using this code suggest us that the real gas effects, such as chemical reaction, are not negligible to predict the hypersonic flow characterisics acculately. ...The results of hypersonic flow analysis using this code suggest us that the real gas effects, such as chemical reaction, are not negligible to predict the hypersonic flow characterisics acculately.

A brief review of investigations in the field of advanced structural concepts and structure member with the aim of making a forecast of hypersonic and aerospace vehicle development is given. Methods of material choice for a hot and thermal protected structure is discussed.

This paper presents the theory of an insulation-radiation cooling method applicable to expandable hypersonic vehicles; two simple configurations, a sphere and a cylinder, are analyzed to illustrate this method.

The development of simulation codes for hypersonic flow computations is the pacing ilea in the definition of a reentry vehicule such as the European HERMES, in order to complement the experimental facilities which cannot cover the complete flight envelope.

This work aims to expand the applicability of an open-source numerical tool to solve hypersonic gas dynamic flows for space propulsion geometries. This is done by validating the code using two well-known hypersonic test cases, the double cone and the hollow cylinder flare, used by the NATO Research and Technology Organization for the validation of hypersonic flight for laminar viscous-inviscid interactions (D. ...This is done by validating the code using two well-known hypersonic test cases, the double cone and the hollow cylinder flare, used by the NATO Research and Technology Organization for the validation of hypersonic flight for laminar viscous-inviscid interactions (D. ...This is done by validating the code using two well-known hypersonic test cases, the double cone and the hollow cylinder flare, used by the NATO Research and Technology Organization for the validation of hypersonic flight for laminar viscous-inviscid interactions (D. Knight, “RTO WG 10 - Test cases for CFD validation of hypersonic flight,” in 40th AIAA Aerospace Sciences Meeting & Exhibit, 2002).

Hypersonic flows over simple 3-D bodies and a space vehicle are simulated using a real-gas Navier- Stokes code under an equilibrium air assumption.

An engineering thermal management computational tool capable of performing component, subsystem, and system level thermal management assessment, design and optimization is the subject of this paper. The Vehicle Integrated Thermal MAnagement Code (VITMAC) simulates the coupled aircraft active cooling system thermal-hydraulics, associated airframe structure thermal response, and vehicle internally/externally generated heat loads. The formulation allows for predicting both the steady-state and transient thermal-hydraulic parameters along the coolant flow paths, as well as the temperature of the surrounding airframe/engine structures, to render the distributions of mass flow rate, pressure, and temperature of the operating fluids throughout the aircraft. Steady-state and transient illustrative examples are presented in this paper to demonstrate code capabilities. These examples show the coupling between the coolant-side thermal-hydraulics and structure-side thermal response.

Hypersonic flight vehicles have potential applications in strategic defence, space missions, and future civilian high-speed transportation systems. ...Scramjet-powered air-breathing hypersonic vehicles experience extreme heat loads induced by combustion, shock waves and viscous heat dissipation.

Despite recent advancements in the physics and chemistry of high temperature air flows, large uncertainties remain to be reduced. Numerical procedures are necessary for advancement of understanding and modeling of their effects. Unfortunately, they have complex effects on the complex shapes of orbiter like U.S. Shuttle Orbiter and Hermes, and on the flight-test results, where they are mixed together with other complex phenomena, related to viscous flows. For clarification of the engineering implication of modeling uncertainties, some results of comparisons are given for different physical and chemical modeling on the simple shape of an AOTV. They emphasize the effect on the pitching moment and on the heat transfer, and give correlated variations in the bow shock wave, conclusions are given on the research to be pushed, and its inclusion in the Hermes aerothermal research program, presently in progress amongst the European scientific community.

Two-stage-to-orbit (TSTO) conceptual-level vehicle designs were evolved by the Lockheed-California Company in the mid-1960s. The purpose was to provide a vehicle-systems-level basis for assessing the payload performance potential of a new class of Stage 1 propulsion systems: combined-cycle airbreathing/rocket engines. TSTO configurations were also established as conventional all-rocket and all-airbreathing engine comparison cases. These vehicle designs and their operating characteristics, along with their orbital payload-delivery capabilities, are presented for consideration by today's space transportation systems planning community.

Officials and engineers at Boeing in Seattle are offering a glimpse into their vision for hypersonic air travel. They have released, for the first time, images of one of the company’s hypersonic air vehicle concepts for potential military and commercial passenger transport. ...They have released, for the first time, images of one of the company’s hypersonic air vehicle concepts for potential military and commercial passenger transport.

The results of computational investigations carried out to clarify the possibilities of hydrogen scramjet thrust uprating in hypersonic flight (M >8) by adding to the fuel substances with higher density are presented. Thrust, specific impulse and density impulse are calculated while adding nitrogen, oxygen, water or inert liquated gases. ...For scramjet boosting in hypersonic flight it is suggested to add oxygen to stoichiometric part of hydrogen instead of excessive part of hydrogen.

A single lightweight engine capable of operating over a wide range of Mach numbers from startup to the hypersonic regime is proposed for automobiles and airplanes. Traditional piston engines, turbojet engines, and scram jet engines operate only under a narrower range of conditions.

Trip time requirements between points on earth can be reduced by use of hypersonic aircraft if the range is sufficiently large so as to minimize the effect on average speed of the time of acceleration and deceleration. ...The study encompasses consideration of the propulsive performance of a hypersonic ramjet design featuring lift augmentation. Particular attention is given to the influence of geometry, equivalence ratio, diffuser recovery characteristics, and boundary layer bleed on this performance. ...The results of the study indicate that present state-of-the-art in propulsion, aerodynamics, insulation, cooling, and structures can provide a hypersonic airbreathing transport capability. A 700,000 lb configuration could transport the above payload 3600 nautical miles with a fuel reserve adequate for descent and landing techniques similar to those used in present transport operation.

Supercritical cryogenic hydrogen is being considered as a coolant for certain high heat flux thermal management applications, including hypersonic vehicles such as the National Aero-Space Plane and high power spacecraft systems for the Strategic Defense Initiative.

Examples are presented for aircraft with highly flexible structure, reentry vehicle with lateral departure tendency, and hypersonic vehicle with extreme forward instantaneous center of rotation. Common design practices, including sensor blending, control mixing and vehicle configuration design changes, to eliminate the NMP response are first described.

The development study is going to be implemented by three steps of verification test, (1) sea level static test, (2) hypersonic simulation test with wind tunnel and (3) actual flight test with a flying test bed. We are now in the first step which was initiated in 1988 and will be accomplished in 1991.

The scope of this paper includes the advantages of this system in comparison to a hypersonic type passenger aeroplane.

The primary application of these devices is to remove heat from compact gallium arsenide diode wafers used in laser communications, but they can also be applied to a variety of other applications ranging from high density electronic packaging to hypersonic surfaces. The coolers were designed to absorb heat fluxes of over 100 W/cm2 with minimal surface temperature gradients.

This spacecraft can accomplish a high performance, 3000 nautical mile lateral range mission, by combining the glide available from its medium hypersonic L/D (1. 7 to 2. 3) with subsonic cruise in the atmosphere. In this application, it excels low L/D spacecraft requiring orbit maneuvers to enhance lateral range.