Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Design verification”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

xEMU Helmet and Extravehicular Visor Assembly (EVVA) Hardware

The Exploration Extravehicular Mobility Unit (xEMU) spacesuit team at NASA’s Johnson Space Center has focused on the development and detailed design of the xEMU to support missions to the International Space Station (ISS) and a moon landing in 2024. This paper focuses on the development and baseline detailed design of the xEMU Helmet and Extravehicular Visor Assembly (EVVA) for the xEMU. This paper will outline the challenging technical requirements, significant architectural trades, technical solutions required to overcome these challenges, and a status of the detailed design. The preliminary results of Design Verification Testing (DVT) as it relates specifically to Helmet and EVVA will also be provided, along with a forward strategy for final maturation into a flight-ready design.

Spacesuit↗
DOE OSTI2022

Multiscale Experiments and Multiphysics Simulation of Multiphase Flow for Transportable Small Modular Reactors

A new type of safe, small, transportable nuclear reactor would address the intense and ever-growing global demand for energy produced via a resilient, carbon-free energy source. In this regard, transportable small modular reactors (SMRs) are being designed and developed for electricity generation within small/micro-grid/off-grid isolated systems, as well as for heat generation in industrial/residential applications. These reactors feature the capability to be fully factory fabricated and then directly transported to utilities’ sites as “plug-and-play” systems. Research and development (R&D) programs are underway at Idaho National Laboratory (INL) to successfully design, develop, and demonstrate such safe-by-design mobile reactor technologies, in collaboration with partner organizations. Multiscale experimental facilities and multiphysics simulation tools are required for reactor design verification and validation (V&V), and licensing. These advanced reactors are intended to feature passive safety systems such as passive containment cooling systems (PCCS), which consist of multiphase flows and multispecies distributions. This seminar talk will focus on designing and analyzing transportable SMR PCCS by using multiscale experiments and multiphysics computational fluid dynamics (CFD) simulations to support reactor licensing and safety. The corresponding research challenges are addressed via supportive verification and validation results generated by the models and simulation tools in combination with selective parametric and uncertainty analysis. This solution approach could blaze the trail for commercial adoption of such technologies. The facilities, simulation capabilities, and research opportunities available at INL in regard to such reactors and the integrated energy systems with which they go hand in hand are also discussed briefly, and may spark interest in deeper research as well as new collaborative projects.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
NASA NTRS1984

Space Station automated systems testing/verification and the Galileo Orbiter fault protection design/verification

Aspects of Space Station automated systems testing and verification are discussed, taking into account several program requirements. It is found that these requirements lead to a number of issues of uncertainties which require study and resolution during the Space Station definition phase. Most, if not all, of the considered uncertainties have implications for the overall testing and verification strategy adopted by the Space Station Program. A description is given of the Galileo Orbiter fault protection design/verification approach. Attention is given to a mission description, an Orbiter description, the design approach and process, the fault protection design verification approach/process, and problems of 'stress' testing.

Landano, M. R.↗
NASA NTRS1974

Space shuttle OMS helium regulator design and development

Analysis, design, fabrication and design verification testing was conducted on the technological feasiblity of the helium pressurization regulator for the space shuttle orbital maneuvering system application. A prototype regulator was fabricated which was a single-stage design featuring the most reliable and lowest cost concept. A tradeoff study on regulator concepts indicated that a single-stage regulator with a lever arm between the valve and the actuator section would offer significant weight savings. Damping concepts were tested to determine the amount of damping required to restrict actuator travel during vibration. Component design parameters such as spring rates, effective area, contamination cutting, and damping were determined by test prior to regulator final assembly. The unit was subjected to performance testing at widely ranging flow rates, temperatures, inlet pressures, and random vibration levels. A test plan for propellant compatibility and extended life tests is included.

Wichmann, H.↗
NASA NTRSDate not supplied

xPLSS Structural Backplate Design, Manufacture, and Test Overview

NASA Johnson Space Center (JSC) has been developing and building a new detailed design of the Exploration Extravehicular Mobility Unit (xEMU) space suit to support future International Space Station (ISS) and Lunar Artemis missions. The Exploration Portable Life Support System (xPLSS) of the xEMU contains some clever new technologies to meet the requirements to provide Extra Vehicular Activity (EVA) capability on the ISS and the Moon. The suit must interface with and fit through ports and airlocks of at least three vehicles: ISS, Human Landing System (HLS), and Gateway. The first partial xPLSS experimental flight unit called SWME EXPRESS Rack Flight Experiment (SERFE) that was a rack-deployed thermal control system payload on the ISS for two years (2020-2022). The first complete assembly of the xEMU was built as a Design Verification Test (DVT) unit (2022); similar to but more extensive than an Engineering Development Unit (EDU). The xPLSS Backplate serves not only as the structural backbone of the xPLSS and SERFE systems but also contains innovative design features to reduce the: mass, complexity, parts count, number ofseals (and therefore leak potential), and outer dimensions of the entire assembly. This paper provides an overview of these new design features, manufacturing processes, system interfaces, and SERFE/DVT test results of the Backplate as part of the xPLSS/xEMU.

xPLSS↗
NASA NTRS2023

xPLSS Structural Backplate Design, Manufacture, and Test Overview

NASA Johnson Space Center (JSC) has been developing and building a new detailed design of the Exploration Extravehicular Mobility Unit (xEMU) space suit to support future International Space Station (ISS) and Lunar Artemis missions. The Exploration Portable Life Support System (xPLSS) of the xEMU contains some clever new technologies to meet the requirements to provide Extra Vehicular Activity (EVA) capability on the ISS and the Moon. The suit must interface with and fit through ports and airlocks of at least three vehicles: ISS, Human Landing System (HLS), and Gateway. The first partial xPLSS experimental flight unit called SWME EXPRESS Rack Flight Experiment (SERFE) that was a rack-deployed thermal control system payload on the ISS for two years (2020-2022). The first complete assembly of the xEMU was built as a Design Verification Test (DVT) unit (2022); similar to but more extensive than an Engineering Development Unit (EDU). The xPLSS Backplate serves not only as the structural backbone of the xPLSS and SERFE systems but also contains innovative design features to reduce the: mass, complexity, parts count, number ofseals (and therefore leak potential), and outer dimensions of the entire assembly. This paper provides an overview of these new design features, manufacturing processes, system interfaces, and SERFE/DVT test results of the Backplate as part of the xPLSS/xEMU.

xPLSS↗
NASA NTRS1992

Circuit design tool. User's manual, revision 2

The CAM chip design was produced in a UNIX software environment using a design tool that supports definition of digital electronic modules, composition of these modules into higher level circuits, and event-driven simulation of these circuits. Our design tool provides an interface whose goals include straightforward but flexible primitive module definition and circuit composition, efficient simulation, and a debugging environment that facilitates design verification and alteration. The tool provides a set of primitive modules which can be composed into higher level circuits. Each module is a C-language subroutine that uses a set of interface protocols understood by the design tool. Primitives can be altered simply by recoding their C-code image; in addition new primitives can be added allowing higher level circuits to be described in C-code rather than as a composition of primitive modules--this feature can greatly enhance the speed of simulation.

Miyake, Keith M.↗
NASA NTRS1986

Orbital maneuvering vehicle thermal design and analysis techniques

This paper describes the OMV thermal design that is required to maintain components within temperature limits for all mission phases. A key element in the OMV thermal design is the application of a motorized thermal shade assembly that is a replacement for the more conventional variable conductance heat pipes or louvers. The thermal shade assembly covers equipment module radiator areas, and based upon the radiator temperature input to onboard computer, opens and closes the shade, varying the effective radiator area. Thermal design verification thermal analyses results are presented. Selected thermal analyses methods, including several unique subroutines, are discussed. A representation of enclosure Script F equations, in matrix form, is also included. Personal computer application to the development of the OMV thermal design is summarized.

Chapter, J.↗
NASA NTRS1972

Design and development of a prototype wet oxidation system for the reclamation of water and the disposition of waste residues onboard space vehicles

Laboratory investigations to define optimum process conditions for oxidation of fecal/urine slurries were conducted in a one-liter batch reactor. The results of these tests formed the basis for the design, fabrication, and testing of an initial prototype system, including a 100-hour design verification test. Areas of further development were identified during this test. Development of a high pressure slurry pump, materials corrosion studies, oxygen supply trade studies, comparison of salt removal water recovery devices, ammonia removal investigation, development of a solids grinder, reactor design studies and bearing life tests, and development of shutoff valves and a back pressure regulator were undertaken. The development work has progressed to the point where a prototype system suitable for manned chamber testing can be fabricated and tested with a high degree of confidence of success.

Jagow, R. B.↗
NASA NTRS2012

Nonlinear Dynamic Modeling and Controls Development for Supersonic Propulsion System Research

This paper covers the propulsion system component modeling and controls development of an integrated nonlinear dynamic simulation for an inlet and engine that can be used for an overall vehicle (APSE) model. The focus here is on developing a methodology for the propulsion model integration, which allows for controls design that prevents inlet instabilities and minimizes the thrust oscillation experienced by the vehicle. Limiting thrust oscillations will be critical to avoid exciting vehicle aeroelastic modes. Model development includes both inlet normal shock position control and engine rotor speed control for a potential supersonic commercial transport. A loop shaping control design process is used that has previously been developed for the engine and verified on linear models, while a simpler approach is used for the inlet control design. Verification of the modeling approach is conducted by simulating a two-dimensional bifurcated inlet and a representative J-85 jet engine previously used in a NASA supersonics project. Preliminary results are presented for the current supersonics project concept variable cycle turbofan engine design.

Connolly, Joseph W.↗
NASA NTRS2022

Permutations of the Exploration Extra-vehicular Mobility Unit (xEMU) for Mission Specific Objectives

The Advanced Portable Life Support System began first with NASA investment during the Constellation Program focused on new technologies that were central to the new architecture but with a consideration for development of the most flexible and adaptable design to address the varied future needs for Extra-Vehicular Activity (EVA) capability by the agency as part of the exploration of the moon and beyond. Since that time, the Portable Life Support System (PLSS) architecture has been demonstrated at bread-board level, packaged prototype level with Human In-The Loop (HITL) testing, and has now matured into what has become known as the Exploration Extravehicular Mobility Unit (xEMU) PLSS focused on a demonstration on the International Space Station (ISS) and support for initial lunar missions. The xEMU completed Preliminary Design Review (PDR) and the associated Safety Review Panel (SRP) Phase I reviews in 2019-2020 and is progressing through the Design Verification Test (DVT) phase in 2021. As the agency updates planning for lunar both near term, long term, and beyond, there are many possible permutations of the existing architecture that can be accommodated to enable varied mission objectives. This paper will discuss the current baseline DVT design for xEMU as well as potential permutations of the PLSS architecture to accomplish an Apollo style short-duration down and out mission, a long term lunar ultra-lightweight approach, as well as a potential SuitPort accommodating architecture.

Colin Campbell↗
NASA NTRS1979

Test verification of a turbofan partial swirl afterburner

Flamespreading velocities exceeding conventional turbulent flamespreading values were demonstrated in a strong centrifugal flow field. This centrifugal flow field flamespreading concept was integrated into an F100 turbofan engine afterburner by introducing swirling airflow into the afterburner. Successful tests were conducted on F100 Engine P072 at sea level and at altitude conditions in a test chamber. This paper summarizes the design approach, engine design verification tests and performance data. Engine tests showed the swirl afterburner increased fuel-air capability improving combustion stability at adverse conditions for combustion in the engine flight envelope. No engine performance or durability degradation was observed.

Hanloser, K. J.↗
NASA NTRS1982

Development of a static feed water electrolysis system

A one person level oxygen generation subsystem was developed and production of the one person oxygen metabolic requirements, 0.82 kg, per day was demonstrated without the need for condenser/separators or electrolyte pumps. During 650 hours of shakedown, design verification, and endurance testing, cell voltages averaged 1.62 V at 206 mA/sq cm and at average operating temperature as low as 326 K, virtually corresponding to the state of the art performance previously established for single cells. This high efficiency and low waste heat generation prevented maintenance of the 339 K design temperature without supplemental heating. Improved water electrolysis cell frames were designed, new injection molds were fabricated, and a series of frames was molded. A modified three fluid pressure controller was developed and a static feed water electrolysis that requires no electrolyte in the static feed compartment was developed and successfully evaluated.

Schubert, F. H.↗
DOE OSTI2021

Nimble Feedthrough Qualification - 125% High Explosive Overpressure Test Plan RevA

The primary purpose of this High Explosive (HE) Over-Pressure Test (OPT) is to qualify top cover diagnostic feedthroughs that will be used on LLNL Nimble Subcritical Experiment (SCE) Series designs per experimental design verification requirements specified in ASME Boiler and Pressure Vessel Code Case 2564, Impulsively-Loaded Pressure Vessels, Section VIII, Division 3; and to satisfy the over-test requirement of DOE-STD-1212. The diagnostic feedthroughs are part of the Vessel Confinement System (VCS), which is credited as a Safety Significant Design Feature per the U1a Facility Documented Safety Analysis (DSA). The OPT will be conducted at the LANL Area 1, R306 Firing Site (TA-15-R306) in a 3-foot diameter VCS depicted in Figure 1.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
NASA NTRS1992

The role of failure/problems in engineering: A commentary of failures experienced - lessons learned

The written version of a series of seminars given to several aerospace companies and three NASA centers are presented. The results are lessons learned through a study of the problems experienced in 35 years of engineering. The basic conclusion is that the primary cause of problems has not been mission technologies, as important as technology is, but the neglect of basic principles. Undergirding this is the lack of a systems focus from determining requirements through design, verification, and operations phases. Many of the concepts discussed are fundamental to total quality management (TQM) and can be used to augment this product enhanced philosophy. Fourteen principles are addressed with problems experienced and are used as examples. Included is a discussion of the implication of constraints, poorly defined requirements, and schedules. Design guidelines, lessons learned, and future tasks are listed. Two additional sections are included that deal with personal lessons learned and thoughts on future thrusts (TQM).

Ryan, R. S.↗
NASA NTRS1972

Development of Lightweight Material Composites to Insulate Cryogenic Tanks for 30-Day Storage in Outer Space

A conceptual design was developed for an MLI system which will meet the design constraints of an ILRV used for 7- to 30-day missions. The ten tasks are briefly described: (1) material survey and procurement, material property tests, and selection of composites to be considered; (2) definition of environmental parameters and tooling requirements, and thermal and structural design verification test definition; (3) definition of tanks and associated hardware to be used, and definition of MLI concepts to be considered; (4) thermal analyses, including purge, evacuation, and reentry repressurization analyses; (5) structural analyses (6) thermal degradation tests of composite and structural tests of fastener; (7) selection of MLI materials and system; (8) definition of a conceptual MLI system design; (9) evaluation of nondestructive inspection techniques and definition of procedures for repair of damaged areas; and (10) preparation of preliminary specifications.

Krause, D. R.↗
NASA NTRS1994

Development Status of the NASA 30-cm Ion Thruster and Power Processor

Xenon ion propulsion systems are being developed by NASA Lewis Research Center and the Jet Propulsion Laboratory to provide flight qualification and validation for planetary and earth-orbital missions. In the ground-test element of this program, light-weight (less than 7 kg), 30 cm diameter ion thrusters have been fabricated, and preliminary design verification tests have been conducted. At 2.3 kW, the thrust, specific impulse, and efficiency were 91 mN, 3300 s, and 0.65, respectively. An engineering model thruster is now undergoing a 2000 h wear-test. A breadboard power processor is being developed to operate from an 80 V to 120 V power bus with inverter switching frequencies of 50 kHz. The power processor design is a pathfinder and uses only three power supplies. The projected specific mass of a flight unit is about 5 kg/kW with an efficiency of 0.92 at the full-power of 2.5 kW. Preliminary integration tests of the neutralizer power supply and the ion thruster have been completed. Fabrication and test of the discharge and beam/accelerator power stages are underway.

Sovey, James S.↗