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Empowering Soldiers Through ISPDS Dispensable Gels vs Gap Filler Pads An Analysis of Thermal Management Materials Electronic Warfare Vying for Control of the Electromagnetic Spectrum More Bang for the Buck A New Design and Manufacturing Method for Deep Penetrating Bomb Cases A Comprehensive Way to Use Bonding to Improve RF Performance of Low Noise Amplifiers Army and Universities Deploy New Warfighter Communication Technology Radiation Effects on Electronics in Aligned Carbon Nanotube Technology (RadCNT) Characterizing the fundamental mechanisms and charge transport phenomena governing the interactions between ionizing and non-ionizing radiation with carbon-based (nanotube and graphene) field-effect transistors (FETs) devices and integrated circuits (ICs).

The High Speed Civil Transport (HSCT) will be exposed to elevated temperatures during Mach 2.4 supersonic flight. While not as extreme as those encountered in other high speed flight efforts (NASP, Shuttle), thermal effects will impact decisions in almost all areas of material selection and design. Accurate temperatures are required to evaluate materials, structural concepts, cooling requirements, etc. Analyses show the importance of structural configuration, use of fuel as a heat sink, and surface properties on structural temperatures. Capability to accurately determine convection and radiation boundary conditions is important for future HSCT design.

This paper describes a computational engineering level assessment tool developed for the design and optimization of thermal management systems for advanced hypersonic and supersonic aircraft. The tool, entitled Vehicle Integrated Thermal MAnagement Code (VITMAC), simulates the coupled thermal response of the aircraft's active cooling systems, structures, fuel tanks, and engines.

The benefits of fuel as a heat sink are well documented: less ram drag, smaller heat exchangers and ducting, and more stable temperatures. Prior to the mid-1970's use of fuel as a heat sink was fairly limited to supersonic flight, where ram air is very hot. Use of fuel to cool auxiliary oil systems (hydraulics, generators, gear boxes) throughout the entire flight envelope has been developed in the F-15, F-16, F-18, and X-29 aircraft. Adding the ECS load to the fuel-cooling system is the current focus. This has led to a large increase in the complexity and level of integration associated with fuel cooling. To make fuel-cooling effective there must be greater thermal management; this means more emphasis on load management and mission planning. The goal is to minimize the supplemental ram air-cooling needed. The integration is especially complex in a stealth vehicle which is intended for multiple mission roles.

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.

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.

A study has been conducted to establish the Mach number limits of noncryogenic fuels used for manned hypersonic cruise missions. This paper specifically presents results for hydrocarbon fuels similar to JP-7.

Hypervelocity endo/exoatmospheric vehicles experience extremely severe thermal conditions, requiring an integrated vehicle-wide approach to thermal management. The paper presents a discussion of key thermal management and environmental control issues with examples from two classes of vehicles, namely a Mach 6 interceptor aircraft and a single-stage-to-orbit vehicle. The elements of a general thermal management optimization methodology are discussed. Trade study results between a single-phase and a two-phase cooling loop used on the single-stage-to-orbit vehicle are also presented.

Market growth and technological advances are expected to lead to a new generation of long-range transports that cruise at supersonic or even hypersonic speeds. Current NASA/industry studies will define the market windows in terms of time frame, Mach number, and technology requirements for these aircraft.

The potential advantages of hypersonic vehicles compatible with missions combining more than one cruise flight regime are developed. ...Gasdynamic heating is discussed as one of the most challenging areas in the development of their propulsion systems, and the role of thermal management on the design of hypersonic vehicles is emphasized. Mixed missions result in vehicles with higher structural efficiency and lower fuel equivalence ratios, and these benefits are presented in terms of their effect on range.