A Review of United States Air Force and Department of Defense Aerospace Propulsion Needs (2006) / Chapter Skim
Currently Skimming:
6 Cross-cutting Technologies
6 Cross-cutting Technologies
Pages 203-215
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 203... ...
6 Cross-cutting Technologies INTRODUCTION This chapter discusses two technology areas that have the potential to yield dramatic improvements in aerospace propulsion -- namely, fuels and materials. While the ensuing discussion and recommendations are related primarily to air-breathing propulsion, advances in fuels and materials research are applicable also to access-to-space and in-space propulsion; those applications are discussed in Chapter 4 and Chapter 5.
|
From page 204... ...
Jet fuels are complex, and technology transition often involves multiple partners such as engine companies, airframers, fuel system suppliers, additive manufacturers, university researchers, the Air Force Petroleum Office, the Defense Energy Support Center, and the Air Force system program offices. Also, coordination with commercial aviation and industry through the International Air Transport Association, the American Society for Testing and Materials, the Federal Aviation Administration, and the North Atlantic Treaty Organization is required.
|
From page 205... ...
CROSS-CUTTING TECHNOLOGIES 205 sensors (such as might be used for onboard monitoring of fuel system health) might also benefit from advances in nano fuel technology.
|
From page 206... ...
Hydrocarbons are relatively poor performers compared to hydrogen, with the key challenge being effective ways to add energy to the hydrocarbon without compromising the stability of the propellant during use. The current approach pursued by NASA and the Air Force is to add strain energy to the propellant by forming three-carbon rings and triple bonds.
|
From page 207... ...
Recommendation 6-1. The Air Force should initiate a 5- to 7-year comprehensive program of fundamental fuels research.
|
From page 208... ...
. With respect to current Air Force requirements, materials in today's commercial engines are primarily stressed during takeoff and spend most of their life at much cooler cruise conditions.
|
From page 209... ...
The Air Force should fund ManTech at a level sufficient to enable future advances in materials for propulsion technology. High-Temperature Structural Materials Advances in materials for turbine engines over the past 60 years have lead to higher operating temperatures that, in turn, have produced higher efficiency.
|
From page 210... ...
210 A REVIEW OF AEROSPACE PROPULSION NEEDS Refractory 2800 ) Intermetallics and Ceramics (°F 2600 ure 2400 erat 2200 MP Ni: TBC's on Ni Alloys 1453°C (2647°F)
|
From page 211... ...
CROSS-CUTTING TECHNOLOGIES 211 required for operation at higher temperatures. The refractory metals will require new coating technologies to make them suitable for use in air-breathing engines.
|
From page 212... ...
212 A REVIEW OF AEROSPACE PROPULSION NEEDS Such high-performance engines are facing additional durability issues related to heat release through the turbine as energetic species emitted from the combustor are further oxidized. The problem needs to be addressed for design and control of reactive cooling techniques employing endothermically cracking JP-8 fuel.
|
From page 213... ...
CROSS-CUTTING TECHNOLOGIES 213 Small scale, real-time staging provides an enhanced Aero Design Ratio + Space for superior performance and reduced exhaust emissions -Fuel-Air + Attributes: · Sustained Performance Over Wide Operating encyiicffE Range Optimal fuel air ratio modulation Combustor Accelerated reaction rates / combustion Loading + Increased Mach # / flame stabilization Non-Intrusive Optical Strain Active Control Dual fuel system capable (liquid, supercritical) and Pressure Sensors Reduced Repair Costs · Maintenance Free Emphasis*
|
From page 214... ...
214 A REVIEW OF AEROSPACE PROPULSION NEEDS Also, the air vehicle mission profiles bound thermal management options. For example, a long-range supersonic aircraft cruising at 50,000 ft with Mach greater than 2 has a high heat load but also a high fuel heat sink capacity, whereas a loitering unmanned combat air vehicle has a high heat load but a low (available)
|
From page 215... ...
"Aerospace fuels/thermal management," Presentation to the committee on April 5, 2005. Dallis Hardwick, Air Force Research Laboratory.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.