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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 397 records · Page 22

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NASA NTRS2019

Rewet Temperature Correlations for Liquid-Nitrogen Boiling Pipe Flows Across Varying Flow Conditions and Orientations

In many convective liquid-vapor phase change heat transfer engineering applications, cryogenic fluids are widely used in industrial processes, spacecraft and cryosurgery systems, and so on. For example, cryogens are usually used as liquid fuels such as liquid hydrogen and oxygen in the rocket industry, liquid nitrogen (LN2) and helium are frequently used to cool superconducting magnetic device for medical applications. In these systems, proper transport, handling, and storage of cryogenic fluids are of extreme importance. Among all the cryogenic transport processes performed in room temperatures, quenching, also termed chilldown, is a unavoidable initial, transient phase-change heat transfer process that brings the system down to the cryogenic condition. The Leidenfrost temperature or rewet temperature that signals the end of film boiling is practically considered the completion point of a quenching process. Therefore, rewet temperature has been considered the most important parameter for the engineering design of cryogenic thermal management systems. As most of the previous correlations for predicting the Leidenfrost temperature and the rewet temperature have been basically developed for water, they are shown to disagree with recent liquid nitrogen pipe chilldown experiments in upward and downward flow directions over a wide range of flow rates, pressures, and degrees of inlet subcooling. In addition to a complete review of the literature, two new correlations are presented in this work, one based on bubble growth and another based on the theoretical maximum limit of superheat. Each correlation performs well over the entire data set.

liquid nitrogen↗

NASA NTRS1971

Alternate Concepts Study Extension. Volume 1: Executive Summary

An analysis of alternate space shuttle concepts is presented. The two main program alternatives are: (1) phased booster development with an interim solid rocket engine cluster preceding the reusable booster and (2) phased orbiter development with modified avionics, vehicle subsystems, thermal protection system, and redesigned rocket engines. Diagrams of the various concepts are provided. The predicted spacecraft performance capabilities are reported. Project management proposals are submitted.

Source record↗

NASA NTRS1958

Some Effects of Rapid Inlet Pressure Oscillation on the Operation of a Turbojet Engine

A program was conducted in an altitude facility at the NACA Lewis laboratory to investigate the effects of rapid inlet pressure oscillations on the operation of a current turbo jet engine. These pressure oscillations were approximately sinusoidal in form and were generated to cover a frequency range of 2 to 75 cycles per second and an amplitude range of 10 to 70 percent of the free-stream total pressure. As the oscillation progressed through the compressor, the amplitude was attenuated considerably and a relatively large phase shift (lag) occurred. Engine stall limits obtained during pressure oscillations differed from quasi-steady-state stall limits as defined by over-all compressor pressure ratio.

Russey, Robert E.↗

NASA NTRS1990

Airflow Model Testing to Determine the Distribution of Hot Gas Flow and O/F Ratio Across the Space Shuttle Main Engine Main Injector Assembly

Engine 0209, the certification engine for the new Phase 2+ Hot Gas Manifold (HGM), showed severe deterioration of the Main Combustion Chamber (MCC) liner during hot fire tests. One theory on the cause of the damage held that uneven local distribution of the fuel rich hot gas flow through the main injector assembly was producing regions of high oxidizer/fuel (O/F) ratio near the wall of the MCC liner. Airflow testing was proposed to measure the local hot gas flow rates through individual injector elements. The airflow tests were conducted using full scale, geometrically correct models of both the current Phase 2 and the new Phase 2+ HGMs. Different main injector flow shield configurations were tested for each HGM to ascertain their effect on the pressure levels and distribution of hot gas flow. Instrumentation located on the primary faceplate of the main injector measured hot gas flow through selected injector elements. These data were combined with information from the current space shuttle main engine (SSME) power balances to produce maps of pressure, hot gas flow rate, and O/F ratio near the main injector primary plate. The O/F distributions were compared for the different injector and HGM configurations.

Mahorter, L.↗

NASA NTRS1991

Airfoil Vibration Dampers program

The Airfoil Vibration Damper program has consisted of an analysis phase and a testing phase. During the analysis phase, a state-of-the-art computer code was developed, which can be used to guide designers in the placement and sizing of friction dampers. The use of this computer code was demonstrated by performing representative analyses on turbine blades from the High Pressure Oxidizer Turbopump (HPOTP) and High Pressure Fuel Turbopump (HPFTP) of the Space Shuttle Main Engine (SSME). The testing phase of the program consisted of performing friction damping tests on two different cantilever beams. Data from these tests provided an empirical check on the accuracy of the computer code developed in the analysis phase. Results of the analysis and testing showed that the computer code can accurately predict the performance of friction dampers. In addition, a valuable set of friction damping data was generated, which can be used to aid in the design of friction dampers, as well as provide benchmark test cases for future code developers.

Cook, Robert M.↗

NASA NTRS2016

Meanline Analysis of Turbines with Choked Flow in the Object-Oriented Turbomachinery Analysis Code

The prediction of turbomachinery performance characteristics is an important part of the conceptual aircraft engine design process. During this phase, the designer must examine the effects of a large number of turbomachinery design parameters to determine their impact on overall engine performance and weight. The lack of detailed design information available in this phase necessitates the use of simpler meanline and streamline methods to determine the turbomachinery geometry characteristics and provide performance estimates prior to more detailed CFD (Computational Fluid Dynamics) analyses. While a number of analysis codes have been developed for this purpose, most are written in outdated software languages and may be difficult or impossible to apply to new, unconventional designs. The Object-Oriented Turbomachinery Analysis Code (OTAC) is currently being developed at NASA Glenn Research Center to provide a flexible meanline and streamline analysis capability in a modern object-oriented language. During the development and validation of OTAC, a limitation was identified in the code's ability to analyze and converge turbines as the flow approached choking. This paper describes a series of changes which can be made to typical OTAC turbine meanline models to enable the assessment of choked flow up to limit load conditions. Results produced with this revised model setup are provided in the form of turbine performance maps and are compared to published maps.

Choked Flow↗

NASA NTRS1979

Comparison of two total energy systems for a diesel power generation plant

The capabilities and limitations, as well as the associated costs for two total energy systems for a diesel power generation plant are compared. Both systems utilize waste heat from engine cooling water and waste heat from exhaust gases. Pressurized water heat recovery system is simple in nature and requires no engine modifications, but operates at lower temperature ranges. On the other hand, a two-phase ebullient system operates the engine at constant temperature, provides higher temperature water or steam to the load, but is more expensive.

Chai, V. W.↗

NASA NTRSDate not supplied

Advanced Concepts Office

Capabilities Overview: About the Advanced Concepts Office - ACO informs decision makers by providing rapid, Pre-Phase A concept designs and studies for space systems - Multi-disciplinary team representing all engineering disciplines - Work Pre-Phase A concept designs and studies - Analysis of alternatives - Quantitative technology assessments - Systems analysis and optimization

Eric C. Sholes↗

NASA NTRS2006

NASA's PEM Fuel Cell Power Plant Development Program for Space Applications

NASA embarked on a PEM fuel cell power plant development program beginning in 2001. This five-year program was conducted by a three-center NASA team of Glenn Research Center (lead), Johnson Space Center, and Kennedy Space Center. The program initially was aimed at developing hardware for a Reusable Launch Vehicle (RLV) application, but more recently had shifted to applications supporting the NASA Exploration Program. The first phase of the development effort, to develop breadboard hardware in the 1-5 kW power range, was conducted by two competing vendors. The second phase of the effort, to develop Engineering Model hardware at the 10 kW power level, was conducted by the winning vendor from the first phase of the effort. Both breadboard units and the single engineering model power plant were delivered to NASA for independent testing. This poster presentation will present a summary of both phases of the development effort, along with a discussion of test results of the PEM fuel cell engineering model under simulated mission conditions.

Hoberecht, Mark↗

NASA NTRS2008

NASA Propulsion Investments for Exploration and Science

The National Aeronautics and Space Administration (NASA) invests in chemical and electric propulsion systems to achieve future mission objectives for both human exploration and robotic science. Propulsion system requirements for human missions are derived from the exploration architecture being implemented in the Constellation Program. The Constellation Program first develops a system consisting of the Ares I launch vehicle and Orion spacecraft to access the Space Station, then builds on this initial system with the heavy-lift Ares V launch vehicle, Earth departure stage, and lunar module to enable missions to the lunar surface. A variety of chemical engines for all mission phases including primary propulsion, reaction control, abort, lunar ascent, and lunar descent are under development or are in early risk reduction to meet the specific requirements of the Ares I and V launch vehicles, Orion crew and service modules, and Altair lunar module. Exploration propulsion systems draw from Apollo, space shuttle, and commercial heritage and are applied across the Constellation architecture vehicles. Selection of these launch systems and engines is driven by numerous factors including development cost, existing infrastructure, operations cost, and reliability. Incorporation of green systems for sustained operations and extensibility into future systems is an additional consideration for system design. Science missions will directly benefit from the development of Constellation launch systems, and are making advancements in electric and chemical propulsion systems for challenging deep space, rendezvous, and sample return missions. Both Hall effect and ion electric propulsion systems are in development or qualification to address the range of NASA s Heliophysics, Planetary Science, and Astrophysics mission requirements. These address the spectrum of potential requirements from cost-capped missions to enabling challenging high delta-v, long-life missions. Additionally, a high specific impulse chemical engine is in development that will add additional capability to performance-demanding space science missions. In summary, the paper provides a survey of current NASA development and risk reduction propulsion investments for exploration and science.

Smith, Bryan K.↗

NASA NTRS2009

Development and Testing of the Orion CEV Parachute Assembly System (CPAS)

The Crew Exploration Vehicle (CEV) is an element of the Constellation Program that includes launch vehicles, spacecraft, and ground systems needed to embark on a robust space exploration program. As an anchoring capability of the Constellation Program, the CEV shall be human-rated and will carry human crews and cargo from Earth into space and back again. Coupled with transfer stages, landing vehicles, and surface exploration systems, the CEV will serve as an essential component of the architecture that supports human voyages to the Moon and beyond. In addition, the CEV will be modified, as required, to support International Space Station (ISS) mission requirements for crewed and pressurized cargo configurations. Headed by Johnson Space Center (JSC), NASA selected Jacobs Engineering as the support contractor to manage the overall CEV Parachute Assembly System (CPAS) program development. Airborne Systems was chosen to develop the parachute system components. General Dynamics Ordnance and Tactical Systems (GD-OTS) was subcontracted to Airborne Systems to provide the mortar systems. Thus the CPAS development team of JSC, Jacobs, Airborne Systems and GD-OTS was formed. The CPAS team has completed the first phase, or Generation I, of the design, fabrication, and test plan. This paper presents an overview of the CPAS program including system requirements and the development of the second phase, known as the Engineering Development Unit (EDU) architecture. We also present top level results of the tests completed to date. A significant number of ground and flight tests have been completed since the last CPAS presentation at the 2007 AIAA ADS Conference.

Lichodziejewski, David↗

NASA NTRS1999

Stirling Space Engine Program: Final Report - Volume 1

The objective of this program was to develop the technology necessary for operating Stirling power converters in a space environment and to demonstrate this technology in full-scale engine tests. Hardware development focused on the Component Test Power Converter (CTPC), a single cylinder, 12.5-kWe engine. Design parameters for the CTPC were 150 bar operating pressure, 70 Hz frequency, and hot-and cold-end temperatures of 1050 K and 525 K, respectively. The CTPC was also designed for integration with an annular sodium heat pipe at the hot end, which incorporated a unique "Starfish" heater head that eliminated highly stressed brazed or weld joints exposed to liquid metal and used a shaped-tubed electrochemical milling process to achieve precise positional tolerances. Selection of materials that could withstand high operating temperatures with long life were another focus. Significant progress was made in the heater head (Udimet 700 and Inconel 718 and a sodium-filled heat pipe); the alternator (polyimide-coated wire with polyimide adhesive between turns and a polyimide-impregnated fiberglass overwrap and samarium cobalt magnets); and the hydrostatic gas bearings (carbon graphite and aluminum oxide for wear couple surfaces). Tests on the CTPC were performed in three phases: cold end testing (525 K), engine testing with slot radiant heaters, and integrated heat pipe engine system testing. Each test phase was successful, with the integrated engine system demonstrating a power level of 12.5 kWe and an overall efficiency of 22 percent in its maiden test. A 1500-hour endurance test was then successfully completed. These results indicate the significant achievements made by this program that demonstrate the viability of Stirling engine technology for space applications.

Dhar, Manmohan↗

NASA NTRS1971

Study to develop improved methods to detect leakage in fluid systems, phase 2

An ultrasonic contact sensor engineering prototype leak detection system was developed and its capabilities under cryogenic operations demonstrated. The results from tests indicate that the transducer performed well on liquid hydrogen plumbing, that flow and valve actuation could be monitored, and that the phase change from gaseous to liquid hydrogen could be detected by the externally mounted transducers. Tests also demonstrate the ability of the system to detect internal leaks past valve seats and to function as a flow meter. Such a system demonstrates that it is not necessary to break into welded systems to locate internal leaks.

Janus, J. C.↗

NASA NTRS1989

Two-dimensional analysis of two-phase reacting flow in a firing direct-injection diesel engine

The flow field, spray penetration, and combustion in two-stroke diesel engines are described. Fuel injection begins at 345 degrees after top dead center (ATDC) and n-dodecane is used as the liquid fuel. Arrhenius kinetics is used to calculate the reaction rate term in the quasi-global combustion model. When the temperature, fuel, and oxygen mass fraction are within suitable flammability limits, combustion begins spontaneously. No spark is necessary to ignite a localized high temperature region. Compression is sufficient to increase the gaseous phase temperature to a point where spontaneous chemical reactions occur. Results are described for a swirl angle of 22.5 degrees.

Nguyen, H. Lee↗

NASA NTRS1980

Orbit transfer vehicle engine study. Volume 3: Program costs

Budgetary and planning cost estimates are presented that were prepared for the development, production and operation and flight support phases for each of the engines proposed for OTV propulsion. The major features of each category engine are described. The development program estimates were structured to the preliminary program Work Breakdown Structures (WBS). Program costs are provided within the applicable WBS elements to Level 4 for each category engine. The production program cost estimates assume a first production lot of 50 units produced at a rate of two units per month. Cumulative average unit costs assume a 90% learning capability. The operations and flight support cost estimates are based on 15, 30 and 45 missions per year for the period 1988 through 1999. Estimated funding requirements were developed for each category and program phase. All cost estimates and funding data are presented in 1979 dollars. The assumptions and ground rules for these estimates are summarized.

Source record↗

NASA NTRS2013

Identification of Noise Sources During Rocket Engine Test Firings and a Rocket Launch Using a Microphone Phased-Array

A 70 microphone, 10-foot by 10-foot, microphone phased array was built for use in the harsh environment of rocket launches. The array was setup at NASA Wallops launch pad 0A during a static test firing of Orbital Sciences' Antares engines, and again during the first launch of the Antares vehicle. It was placed 400 feet away from the pad, and was hoisted on a scissor lift 40 feet above ground. The data sets provided unprecedented insight into rocket noise sources. The duct exit was found to be the primary source during the static test firing; the large amount of water injected beneath the nozzle exit and inside the plume duct quenched all other sources. The maps of the noise sources during launch were found to be time-dependent. As the engines came to full power and became louder, the primary source switched from the duct inlet to the duct exit. Further elevation of the vehicle caused spilling of the hot plume, resulting in a distributed noise map covering most of the pad. As the entire plume emerged from the duct, and the ondeck water system came to full power, the plume itself became the loudest noise source. These maps of the noise sources provide vital insight for optimization of sound suppression systems for future Antares launches.

acoustics↗

NASA NTRS1973

Advanced technology for reducing aircraft engine pollution

The proposed EPA regulations covering emissions of gas turbine engines will require extensive combustor development. The NASA is working to develop technology to meet these goals through a wide variety of combustor research programs conducted in-house, by contract, and by university grant. In-house efforts using the swirl-can modular combustor have demonstrated sizable reduction in NO emission levels. Testing to reduce idle pollutants has included the modification of duplex fuel nozzles to air-assisted nozzles and an exploration of the potential improvements possible with combustors using fuel staging and variable geometry. The Experimental Clean Combustor Program, a large contracted effort, is devoted to the testing and development of combustor concepts designed to achieve a large reduction in the levels of all emissions. This effort is planned to be conducted in three phases with the final phase to be an engine demonstration of the best reduced emission concepts.

Jones, R. E.↗

NASA NTRS1980

Sensor failure and multivariable control for airbreathing propulsion systems

A new sensor/actuator failure analysis technique for turbofan jet engines was developed. Three phases of failure analysis, namely detection, isolation, and accommodation are considered. Failure detection and isolation techniques are developed by utilizing the concept of Generalized Likelihood Ratio (GLR) tests. These techniques are applicable to both time varying and time invariant systems. Three GLR detectors are developed for: (1) hard-over sensor failure; (2) hard-over actuator failure; and (3) brief disturbances in the actuators. The probability distribution of the GLR detectors and the detectability of sensor/actuator failures are established. Failure type is determined by the maximum of the GLR detectors. Failure accommodation is accomplished by extending the Multivariable Nyquest Array (MNA) control design techniques to nonsquare system designs. The performance and effectiveness of the failure analysis technique are studied by applying the technique to a turbofan jet engine, namely the Quiet Clean Short Haul Experimental Engine (QCSEE). Single and multiple sensor/actuator failures in the QCSEE are simulated and analyzed and the effects of model degradation are studied.

Behbehani, K.↗