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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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At least 127 records · Page 7

All sources NASA NTRS DOE OSTI

NASA NTRS1978

An algorithm for optimal structural design with frequency constraints

The paper presents a finite element method for minimum weight design of structures with lower-bound constraints on the natural frequencies, and upper and lower bounds on the design variables. The design algorithm is essentially an iterative solution of the Kuhn-Tucker optimality criterion. The three most important features of the algorithm are: (1) a small number of design iterations are needed to reach optimal or near-optimal design, (2) structural elements with a wide variety of size-stiffness may be used, the only significant restriction being the exclusion of curved beam and shell elements, and (3) the algorithm will work for multiple as well as single frequency constraints. The design procedure is illustrated with three simple problems.

Kiusalaas, J.↗

NASA NTRS2011

Linear Quadratic Tracking Design for a Generic Transport Aircraft with Structural Load Constraints

When designing control laws for systems with constraints added to the tracking performance, control allocation methods can be utilized. Control allocations methods are used when there are more command inputs than controlled variables. Constraints that require allocators are such task as; surface saturation limits, structural load limits, drag reduction constraints or actuator failures. Most transport aircraft have many actuated surfaces compared to the three controlled variables (such as angle of attack, roll rate & angle of side slip). To distribute the control effort among the redundant set of actuators a fixed mixer approach can be utilized or online control allocation techniques. The benefit of an online allocator is that constraints can be considered in the design whereas the fixed mixer cannot. However, an online control allocator mixer has a disadvantage of not guaranteeing a surface schedule, which can then produce ill defined loads on the aircraft. The load uncertainty and complexity has prevented some controller designs from using advanced allocation techniques. This paper considers actuator redundancy management for a class of over actuated systems with real-time structural load limits using linear quadratic tracking applied to the generic transport model. A roll maneuver example of an artificial load limit constraint is shown and compared to the same no load limitation maneuver.

Burken, John J.↗

NASA NTRS1988

Aerodynamic characteristics of wings designed with a combined-theory method to cruise at a Mach number of 4.5

A wind-tunnel study was conducted to determine the capability of a method combining linear theory and shock-expansion theory to design optimum camber surfaces for wings that will fly at high-supersonic/low-hypersonic speeds. Three force models (a flat-plate reference wing and two cambered and twisted wings) were used to obtain aerodynamic lift, drag, and pitching-moment data. A fourth pressure-orifice model was used to obtain surface-pressure data. All four wing models had the same planform, airfoil section, and centerbody area distribution. The design Mach number was 4.5, but data were also obtained at Mach numbers of 3.5 and 4.0. Results of these tests indicated that the use of airfoil thickness as a theoretical optimum, camber-surface design constraint did not improve the aerodynamic efficiency or performance of a wing as compared with a wing that was designed with a zero-thickness airfoil (linear-theory) constraint.

Mack, Robert J.↗

NASA NTRS1992

Extravehicular mobility unit subcritical liquid oxygen storage and supply system

The storage of life support oxygen in the Extravehicular Mobility Unit in the liquid state offers some advantages over the current method of storing the oxygen as a high pressure gas. Storage volume is reduced because of the increased density associated with liquid. The lower storage and operating pressures also reduce the potential for leakage or bursting of the storage tank. The potential for combustion resulting from adiabatic combustion of the gas within lines and components is substantially reduced. Design constraints on components are also relaxed due to the lower system pressures. A design study was performed to determine the requirements for a liquid storage system and prepare a conceptual design. The study involved four tasks. The first was to identify system operating requirements that influence or direct the design of the system. The second was to define candidate storage system concepts that could possibly satisfy the requirements. An evaluation and comparison of the candidate concepts was conducted in the third task. The fourth task was devoted to preparing a conceptual design of the recommended storage system and to evaluate concerns with integration of the concept into the EMU. The results are presented.

Anderson, John↗

NASA NTRS1979

Pointing and control of planetary spacecraft - The next 20 years

Four basic categories of spacecraft pointing and control systems are discussed: (1) spin stabilized, (2) dual spin, (3) three-axis, and (4) momentum bias. Goals, mission requirements, and payloads should be considered for selection of control systems. A set of representative requirements, including life and environmental, vehicle/payload orientation and accuracy requirements, and control-system operational and functional requirements are discussed. Attention is given to design constraints imposed by the system selection. It is noted that sensitivity of any system design to increasing accuracy and flexibility in science-mission reprogramming will be major cost factors.

Mcglinchey, L. F.↗

NASA NTRS1974

Weight estimates for Quiet/STOL aircraft

Attention is drawn to the dependence of Q/STOL weight estimation relationships on design acoustic level, engine selection, high-lift concept, design criteria such as field lengths, range, speed and payload, aircraft geometry, and design constraints such as vehicle cost and fuel prices. Weight estimate considerations with associated configuration and design details are presented. Typical weight estimating relationships being used in a NASA study contract are also included. Some representative future applications of Q/STOL concepts are visualized as (1) fuel conservative configurations utilizing STOL high-life concepts for obtaining relatively higher wing loadings during cruise, and (2) low-wing loading aircraft configurations with short-range, low-passenger capacity, and low fan-passenger-ratio turbo-fan engines for a future interurban air transportation market.

Patterson, R. W.↗

NASA NTRS1985

Image gathering and processing - Information and fidelity

In this paper we formulate and use information and fidelity criteria to assess image gathering and processing, combining optical design with image-forming and edge-detection algorithms. The optical design of the image-gathering system revolves around the relationship among sampling passband, spatial response, and signal-to-noise ratio (SNR). Our formulations of information, fidelity, and optimal (Wiener) restoration account for the insufficient sampling (i.e., aliasing) common in image gathering as well as for the blurring and noise that conventional formulations account for. Performance analyses and simulations for ordinary optical-design constraints and random scences indicate that (1) different image-forming algorithms prefer different optical designs; (2) informationally optimized designs maximize the robustness of optimal image restorations and lead to the highest-spatial-frequency channel (relative to the sampling passband) for which edge detection is reliable (if the SNR is sufficiently high); and (3) combining the informationally optimized design with a 3 by 3 lateral-inhibitory image-plane-processing algorithm leads to a spatial-response shape that approximates the optimal edge-detection response of (Marr's model of) human vision and thus reduces the data preprocessing and transmission required for machine vision.

Huck, F. O.↗

NASA NTRS2010

Aerocapture Guidance and Performance at Mars for High-Mass Systems

The objective of this study is to understand the performance associated with using the aerocapture maneuver to slow high-mass systems from an Earth-approach trajectory into orbit around Mars. This work is done in conjunction with the Mars Entry Descent and Landing Systems Analysis (EDL-SA) task to explore candidate technologies necessary for development in order to land large-scale payloads on the surface of Mars. Among the technologies considered include hypersonic inflatable aerodynamic decelerators (HIADs) and rigid mid-lift to drag (L/D) aeroshells. Nominal aerocapture trajectories were developed for the mid-L/D aeroshell and two sizes of HIADs, and Monte Carlo analysis was completed to understand sensitivities to dispersions. Additionally, a study was completed in order to determine the size of the larger of the two HIADs which would maintain design constraints on peak heat rate and diameter. Results show that each of the three aeroshell designs studied is a viable option for landing high-mass payloads as none of the three exceed performance requirements.

Zumwalt, Carlie H.↗

NASA NTRSDate not supplied

Mission Profiles for the SUSAN Electrofan Concept

The SUbsonic Single Aft eNgine (SUSAN) Electrofan is a novel aircraft concept which utilizes a single aft-mounted engine, electrified aircraft propulsion, an emergency backup battery, as well as state-of-the-art aerodynamic design and thermal management systems to reduce the overall environmental impact of the aircraft. Mission profiles, which define the aircraft state and flight characteristics throughout various phases of flight, are an important component of aircraft conceptual design. These defined characteristics can serve as sizing cases or design constraints. By defining the mission profiles to be within airworthiness certification standards and regulations, aircraft designers can ensure the conceptual design is predicted to be within compliance of these regulations throughout the design process. This paper will present mission profiles for the SUSAN Electrofan aircraft, including the basis for defining the characteristics required during each phase of flight.

Conceptual Design↗

NASA NTRSDate not supplied

Mission Profiles for the SUSAN Electrofan Concept

The Subsonic Single Aft engine (SUSAN) Electrofan is a novel aircraft concept which utilizes a single aft-mounted engine, electrified aircraft propulsion, an emergency backup battery, as well as state-of-the-art aerodynamic design and thermal management systems to reduce the overall environmental impact of the aircraft. Mission profiles, which define the aircraft state and flight characteristics throughout various phases of flight, are an important component of aircraft conceptual design. These defined characteristics can serve as sizing cases or design constraints. By defining the mission profiles to be within airworthiness certification standards and regulations, aircraft designers can ensure the conceptual design is predicted to be within compliance of these regulations throughout the design process. This paper will present mission profiles for the SUSAN Electrofan aircraft, including the basis for defining the characteristics required during each phase of flight.

Conceptual Design↗

NASA NTRS2024

Development of a Single Level Assessment Module for Simulating the Human Factors Concept Trade Space

This paper is a synopsis of the design and development of the Single Level Assessment Module (SLAM), a habitation mockup aimed at simulating volumetric conditions for astronauts in transit to Mars. Utilizing repurposed materials to enable low cost and constrained by various other design requirements from its parent vehicle, the SLAM embodies a critical step towards understanding human/habitat dynamics and interactions within the framework of the Mars Transit Habitat (TH) concept trade space. The synopsis begins by outlining the design constraints and goals, focusing on material availability and functional area volume requirements. Through various 3D design solutions, the SLAM emerges as a versatile habitat prototype, capable of accommodating various functional areas within its reconfigurable framework. The construction phase is then explored, highlighting the practical challenges and solutions encountered in assembling the SLAM's components. From panel assembly to outfitting functional areas, the construction process demonstrates a methodical approach to realizing the habitat's design intent. Looking ahead, the paper outlines future work, emphasizing the SLAM's adaptability for analysis and its potential to inform the design trade space future habitation concepts across the Moon to Mars architecture. By incorporating hinges for reconfigurability and facilitating volume assessments, the SLAM emerges as a crucial tool in advancing NASA’s ability to assess focused habitation configurations in conjunction with the development of the Moon to Mars architecture. In conclusion, this paper showcases the iterative process of habitat design, from conceptualization to construction.

Keith Lindsey↗

DOE OSTI2023

And manufacture of generalized flow profile-producing devices

The present invention provides a process for making a flow conditioning device that transforms an input flow into a desired output flow. The process includes the steps of inputting into a computer program a set of design constraints representative of the input flow and the output flow. The computer program generates a design representative of a flow-conditioning device that transforms the input flow into the output flow. The process then provides the output design to an additive manufacturing or other suitable production system adapted to form a solid representation of the flow-conditioning device.

Ferrar, Anthony M.↗

DOE OSTI2026

Making Small-Volume Heat Pump Water Heaters Larger: A Design Framework for Integrated Phase Change Material Heat Exchangers

Those that use electricity for water heating, the majority use resistive elements rather than heat pump water heaters (HPWHs), the latter of which use 60-70% less energy than the former. One major barrier to wider HPWH adoption is the added equipment required, which prevents current 50-80-gallon tanks on the market from fitting into smaller utility closets sized for 30-40 gallons, such as those found in manufactured housing. Additionally, these smaller HPWHs tend to underperform relative to their larger counterparts. One solution that addresses both space and performance concerns is thermal energy storage, and in particular, phase change materials (PCMs). PCMs have been studied extensively in building envelope and HVAC systems, but remain a nascent technology in residential water heating. While water itself has a uniquely high energy storage capacity, PCMs have an even higher energy storage density, thus providing the potential to elevate the performance of 40-gallon HPWHs to that of 50-gallon or larger tanks. This research is part of a larger project that seeks to utilize thermal energy storage to enable decarbonized water heating in low-income communities. In this study, we outline the design process used to produce novel PCM heat exchangers for use in small-volume HPWH tanks, including the identification of design constraints and performance targets relevant to real-world applications. In order to ensure optimal PCM utilization and tank storage capacity, we focus here on co-maximizing surface area and PCM volume in the heat exchangers; therefore, this research targets triply periodic minimal surface (TPMS) lattices. TPMS lattices boast enhanced heat transfer capabilities compared to traditional heat exchanger geometries and offer highly tailorable designs; thus, they pair well with the growing field of additive manufacturing, or 3D printing. Starting with a suite of TPMS lattices, we demonstrate a systematic approach for narrowing down feasible designs that comply with identified constraints while meeting PCM performance objectives.

25 ENERGY STORAGE↗

DOE OSTI2026

Design Considerations for Phase Change Material-Incorporated Heat Exchangers in Water Heating

In recent years, the buildings sector has seen major pushes towards decarbonization through innovations that promote deep electrification. 20% of an average household's energy use comes from water heating, and in the US, over half of all households still use gas water heaters. Of those that use electricity for water heating, the majority use resistive elements rather than heat pump water heaters (HPWHs), the latter of which use 60-70% less energy than the former. However, HPWHs tend to have larger dimensions, preventing current 50-80-gallon tanks on the market from fitting into smaller utility closets sized for 30-40 gallons, such as those found in manufactured housing. Additionally, these smaller HPWHs tend to underperform relative to their larger counterparts. One solution that addresses both space and performance concerns is thermal energy storage, and in particular, phase change materials (PCMs). This study outlines the design process used to produce novel PCM heat exchangers for use in small-volume HPWH tanks, including the identification of design constraints and performance targets relevant to real-world applications. To ensure optimal PCM utilization and tank storage capacity, this works seeks to co-maximize surface area and PCM volume; therefore, this research targets triply periodic minimal surface (TPMS) lattices, which boast enhanced heat transfer capabilities compared to traditional heat exchanger geometries. Starting with a suite of TPMS lattices, we demonstrate a systematic approach for narrowing down feasible designs that comply with identified constraints while meeting PCM performance objectives. Our current results indicate that tuning lattice properties can effectively produce geometries that provide enough energy storage to achieve a 50-gallon capacity out of a 40-gallon HPWH, even when placing the PCM heat exchanger inside the tank. Additionally, we demonstrate successful fabrication of lattices with these tuned properties.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

NASA NTRS1987

Self-consistent calculations and design considerations for a GaAs nipi doping superlattice solar cell

The authors present design constraints which show that a previously proposed GaAs nipi doping superlattice solar cell structure would not work as an efficient space solar cell. A structure based on the CLEFT process, which shows promise of being an efficient cell with very high radiation tolerance, is proposed. In order to test theoretically its viability and to optimize its design, self-consistent quantum mechanical calculations were made for a number of thicknesses of the n, i, and p layers and the dopings in the n and p layers. These results show that: 1) an i layer is not necessary; in fact, its presence makes it difficult to satisfy one of the key constraints; 2) a near-optimum design with 750-A thick n and p layers with dopings of 2.5E18/cu cm and a selective contact separation of 20 microns would yield both high efficiency and very high radiation tolerance.

Clark, Ralph O.↗

NASA NTRS2002

150 Passenger Commercial Aircraft

It has been projected that the need for a short-range mid-sized, aircraft is increasing. The future strategy to decrease long-haul flights will increase the demand for short-haul flights. Since passengers prefer to meet their destinations quickly, airlines will increase the frequency of flights, which will reduce the passenger load on the aircraft. If a point-to-point flight is not possible, passengers will prefer only a one-stop short connecting flight to their final destination. A 150-passenger aircraft is an ideal vehicle for these situations. It is mid-sized aircraft and has a range of 3000 nautical miles. This type of aircraft would market U.S. domestic flights or inter-European flight routes. The objective of the design of the 150-passenger aircraft is to minimize fuel consumption. The configuration of the aircraft must be optimized. This aircraft must meet CO2 and NOx emissions standards with minimal acquisition price and operating costs. This report contains all the work that has been performed for the completion of the design of a 150 passenger commercial aircraft. The methodology used is the Technology Identification, Evaluation, and Selection (TIES) developed at Georgia Tech Aerospace Systems Design laboratory (ASDL). This is an eight-step conceptual design process to evaluate the probability of meeting the design constraints. This methodology also allows for the evaluation of new technologies to be implemented into the design. The TIES process begins with defining the problem with a need established and a market targeted. With the customer requirements set and the target values established, a baseline concept is created. Next, the design space is explored to determine the feasibility and viability of the baseline aircraft configuration. If the design is neither feasible nor viable, new technologies can be implemented to open up the feasible design space and allow for a plausible solution. After the new technologies are identified, they must be evaluated to determine the physical compatibility of integrating multiple technologies and then the impact on the design, both improvements and degradations, must be determined. These technologies are assessed deterministically. Again, Response Surface Equations (RSEs) are developed to allow for a full factorial evaluation of the combinations of the technologies. The best combination of technologies is selected and then the design space is again reevaluated for feasibility and viability.

Bucovsky, Adrian↗

NASA NTRS2003

The Application of Metal Matrix Composite Materials in Propulsion System Valves

Metal Matrix Composite (MMC) materials have been developed and used in many applications to reduce the weight of components where weight and deflection are the driving design requirement. MMC materials are being developed for use in some propulsion system components, such as turbo-pumps and thrust chambers. However, to date, no propulsion system valves have been developed that take advantage of the materials unique properties. The stiffness of MMC's could help keep valves light or improve life where deflection is the design constraint (such as seal and bearing locations). The low CTE of the materials might allow the designer to reduce tolerances and clearances producing better performance and lighter weight valves. Using unique manufacturing processes allow parts to be plated/coated for longer life and allow joining either by welding or threading/bolting. Additionally, casting of multi part pre-forms to form a single part can lead to designs that would be hard or impossible to manufacture with other methods. Therefore, NASA's Marshall Space Flight Center (MSFC) has developed and tested a prototype propulsion system valve that utilizes these materials to demonstrate these advantages. Through design and testing, this effort will determine the best use of these materials in valves designed to achieve the goal of a highly reliable and lightweight propulsion system. This paper is a continuation of the paper, The Application of Metal Matrix Composite Materials In Propulsion System Valves, presented at the JANNAF Conference held in April, 2002. Fabrication techniques employed, valve development, and valve test results will be discussed in this paper.

Laszar, John↗

NASA NTRS2010

Control Design for a Generic Commercial Aircraft Engine

This paper describes the control algorithms and control design process for a generic commercial aircraft engine simulation of a 40,000 lb thrust class, two spool, high bypass ratio turbofan engine. The aircraft engine is a complex nonlinear system designed to operate over an extreme range of environmental conditions, at temperatures from approximately -60 to 120+ F, and at altitudes from below sea level to 40,000 ft, posing multiple control design constraints. The objective of this paper is to provide the reader an overview of the control design process, design considerations, and justifications as to why the particular architecture and limits have been chosen. The controller architecture contains a gain-scheduled Proportional Integral controller along with logic to protect the aircraft engine from exceeding any limits. Simulation results illustrate that the closed loop system meets the Federal Aviation Administration s thrust response requirements

Csank, Jeffrey↗