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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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NASA NTRSDate not supplied

Development of Acoustic Mufflers for Cabin Noise Reduction in Orion Spacecraft

Controlling cabin acoustic noise levels in the Crew Module (CM) of the Orion spacecraft is critical to ensure adequate speech intelligibility, to avoid fatigue, and prevent any possibility of temporary and permanent hearing loss to the crew. The primary source of cabin noise for the on-orbit phase of the mission is from the Environmental Control and Life Support System (ECLSS) which recycles and conditions breathing air and maintains cabin pressurization through its duct network and components. Unfortunately, as a side effect, noise from the ECLSS fans propagates through theses ducts and emanate into the cabin habitable volume via the ECLSS inlet and outlets. To mitigate excessive duct-borne noise, two ECLSS mufflers have been designed to provide significant acoustic transmission loss (TL) so that the cabin noise requirements can be met. Each muffler is meant to be installed in the ducting of the ECLSS air inlet and outlet sides, respectively. Packaging constraints and tight volume requirements necessitated the mufflers to be of complex geometry and compatible with the bends of the ECLSS duct layout. To design and characterize the acoustic performance of the inlet and outlet mufflers, computational acoustic models were developed using the Finite Element Method (FEM) with 𝑤𝑎𝑣𝑒଺ vibroacoustic software. Characterization of the acoustic material and perforations in the mufflers were addressed with poroelastic theory. Once the mufflers were designed on paper and its TL predicted, prototypes of these mufflers were created using additive manufacturing. The muffler prototypes were subsequently tested for acoustic TL in the laboratory with various con-figurations of acoustic materials. Comparing the analytical predictions to the test performance yielded excellent correlation for acoustic TL and demonstrated significant broadband noise attenuation. The ECLSS mufflers are currently scheduled to be installed on the Artemis II Crew Module (CM) of the Orion spacecraft and will provide significant cabin comfort to crew during the mission.

Indranil Dandaroy↗

NASA NTRS1980

An Innovation in Building Design

Collins & Aikman's flat cable permits elimination of ducts and other accommodations traditionally required for building wiring systems, thus gives designers new latitude in planning attractive "open landscape" office layouts. The big factor is that FCC, whose thickness approximates that of two business cards, can be mounted on walls and floors instead of in them, and can be installed beneath a carpet or along a baseboard. Originating from Apollo's command module, its essential sheathing is designed to look like decor rather than plumbing. This could possibly eliminate traditional ducting under floors and elsewhere necessary to accommodate conventional wiring. Construction costs are reduced by 14 percent.

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NASA NTRS2006

Development of a 32 Inch Diameter Levitated Ducted Fan Conceptual Design

The NASA John H. Glenn Research Center has developed a revolutionary 32 in. diameter Levitated Ducted Fan (LDF) conceptual design. The objective of this work is to develop a viable non-contact propulsion system utilizing Halbach arrays for all-electric flight, and many other applications. This concept will help to reduce harmful emissions, reduce the Nation s dependence on fossil fuels, and mitigate many of the concerns and limitations encountered in conventional aircraft propulsors. The physical layout consists of a ducted fan drum rotor with blades attached at the outer diameter and supported by a stress tuner ring at the inner diameter. The rotor is contained within a stator. This concept exploits the unique physical dimensions and large available surface area to optimize a custom, integrated, electromagnetic system that provides both the levitation and propulsion functions. The rotor is driven by modulated electromagnetic fields between the rotor and the stator. When set in motion, the time varying magnetic fields interact with passive coils in the stator assembly to produce repulsive forces between the stator and the rotor providing magnetic suspension. LDF can provide significant improvements in aviation efficiency, reliability, and safety, and has potential application in ultra-efficient motors, computers, and space power systems.

Eichenberg, Dennis J.↗

NASA NTRS1999

Wave-Rotor-Enhanced Gas Turbine Engine Demonstrator

The U.S. Army Research Laboratory, NASA Glenn Research Center, and Rolls-Royce Allison are working collaboratively to demonstrate the benefits and viability of a wave-rotor-topped gas turbine engine. The self-cooled wave rotor is predicted to increase the engine overall pressure ratio and peak temperature by 300% and 25 to 30%. respectively, providing substantial improvements in engine efficiency and specific power. Such performance improvements would significantly reduce engine emissions and the fuel logistics trails of armed forces. Progress towards a planned demonstration of a wave-rotor-topped Rolls-Royce Allison model 250 engine has included completion of the preliminary design and layout of the engine, the aerodynamic design of the wave rotor component and prediction of its aerodynamic performance characteristics in on- and off-design operation and during transients, and the aerodynamic design of transition ducts between the wave rotor and the high pressure turbine. The topping cycle increases the burner entry temperature and poses a design challenge to be met in the development of the demonstrator engine.

Welch, Gerard E.↗

NASA NTRS1981

Advanced Gas Turbine (AGT) powertrain system development for automotive applications

Preliminary layouts were made for the exhaust system, air induction system, and battery installation. Points of interference were identified and resolved by altering either the vehicle or engine designs. An engine general arrangement evolved to meet the vehicle engine compartment constraints while minimizing the duct pressure losses and the heat rejection. A power transfer system (between gasifier and power turbines) was developed to maintain nearly constant temperatures throughout the entire range of engine operation. An advanced four speed automatic transmission was selected to be used with the engine. Performance calculations show improvements in component efficiencies and an increase in fuel economy. A single stage centrifugal compressor design was completed and released for procurement. Gasifier turbine, power turbine, combustor, generator, secondary systems, materials, controls, and transmission development are reported.

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NASA NTRS1971

Brayton heat exchange unit development program

A Brayton Heat Exchanger Unit (BHXU), consisting of a recuperator, a heat sink heat exchanger and a gas ducting system, was designed, fabricated, and tested. The design was formulated to provide a high performance unit suitable for use in a long-life Brayton-cycle powerplant. A parametric analysis and design study was performed to establish the optimum component configurations to achieve low weight and size and high reliability, while meeting the requirements of high effectiveness and low pressure drop. Layout studies and detailed mechanical and structural design were performed to obtain a flight-type packaging arrangement. Evaluation testing was conducted from which it is estimated that near-design performance can be expected with the use of He-Xe as the working fluid.

Morse, C. J.↗

NASA NTRS1971

Integral lift engine preliminary design

A preliminary mechanical design of a complete lift fan engine system is reported. A description of the lift fan engine, layout drawings of the components and complete engine, and a discussion of the design analyses and results are presented. The design features and areas of analysis include fan and compressor rotor blades of composite construction, a combustor folded over the compressor, relatively high-temperature blades in the high-pressure turbine, the first stage of the low-pressure turbine used for bearing support and ducting of lubricant to the bearings, a complete lubrication system, critical speeds of the shafting, and vibration and flutter of the blading.

Pratt, W.↗

NASA NTRS1973

Brayton heat exchanger unit development program (alternate design)

A Brayton Heat Exchanger Unit Alternate Design (BHXU-Alternate) consisting of a recuperator, a heat sink heat exchanger, and a gas ducting system, was designed and fabricated. The design was formulated to provide a high performance unit suitable for use in a long-life Brayton-cycle powerplant. Emphasis was on double containment against external leakage and leakage of the organic coolant into the gas stream. A parametric analysis and design study was performed to establish the optimum component configurations to achieve low weight and size and high reliability, while meeting the requirements of high effectiveness and low pressure drop. Layout studies and detailed mechanical and structural design were performed to obtain a flight-type packaging arrangement, including the close-coupled integration of the BHXU-Alternate with the Brayton Rotating Unit (BRU).

Duncan, J. D.↗

NASA NTRS1993

NASA advanced design program. Design and analysis of a radio-controlled flying wing aircraft

The main challenge of this project was to design an aircraft that will achieve stability while flying without a horizontal tail. The project focused on both the design, analysis and construction of a remotely piloted, elliptical shaped flying wing. The design team was composed of four sub-groups each of which dealt with the different aspects of the design, namely aerodynamics, stability and control, propulsion, and structures. Each member of the team initially researched the background information pertaining to specific facets of the project. Since previous work on this topic was limited, most of the focus of the project was directed towards developing an understanding of the natural instability of the aircraft. Once the design team entered the conceptual stage of the project, a series of compromises had to be made to satisfy the unique requirements of each sub-group. As a result of the numerous calculations and iterations necessary, computers were utilized extensively. In order to visualize the design and layout of the wing, engines and control surfaces, a solid modeling package was used to evaluate optimum design placements. When the design was finalized, construction began with the help of all the members of the project team. The nature of the carbon composite construction process demanded long hours of manual labor. The assembly of the engine systems also required precision hand work. The final product of this project is the Elang, a one-of-a-kind remotely piloted aircraft of composite construction powered by two ducted fan engines.

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