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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 145 records · Page 8

All sources NASA NTRS DOE OSTI

NASA NTRS2005

Spool Valve for Switching Air Flows Between Two Beds

U.S. Patent 6,142,151 describes a dual-bed ventilation system for a space suit, with emphasis on a multiport spool valve that switches air flows between two chemical beds that adsorb carbon dioxide and water vapor. The valve is used to alternately make the air flow through one bed while exposing the other bed to the outer-space environment to regenerate that bed through vacuum desorption of CO2 and H2O. Oxygen flowing from a supply tank is routed through a pair of periodically switched solenoid valves to drive the spool valve in a reciprocating motion. The spool valve equalizes the pressures of air in the beds and the volumes of air flowing into and out of the beds during the alternations between the adsorption and desorption phases, in such a manner that the volume of air that must be vented to outer space is half of what it would be in the absence of pressure equalization. Oxygen that has been used to actuate the spool valve in its reciprocating motion is released into the ventilation loop to replenish air lost to vacuum during the previous desorption phase of the operating cycle.

Dean, W. Clark↗

NASA NTRS2015

Intelligent Flow Control Valve

The present invention is an intelligent flow control valve which may be inserted into the flow coming out of a pipe and activated to provide a method to stop, measure, and meter flow coming from the open or possibly broken pipe. The intelligent flow control valve may be used to stop the flow while repairs are made. Once repairs have been made, the valve may be removed or used as a control valve to meter the amount of flow from inside the pipe. With the addition of instrumentation, the valve may also be used as a variable area flow meter and flow controller programmed based upon flowing conditions. With robotic additions, the valve may be configured to crawl into a desired pipe location, anchor itself, and activate flow control or metering remotely.

Kelley, Anthony R↗

NASA NTRS2016

Cryogenic Cam Butterfly Valve

A cryogenic cam butterfly valve has a body that includes an axially extending fluid conduit formed there through. A disc lug is connected to a back side of a valve disc and has a circular bore that receives and is larger than a cam of a cam shaft. The valve disc is rotatable for a quarter turn within the body about a lug axis that is offset from the shaft axis. Actuating the cam shaft in the closing rotational direction first causes the camming side of the cam of the cam shaft to rotate the disc lug and the valve disc a quarter turn from the open position to the closed position. Further actuating causes the camming side of the cam shaft to translate the valve disc into sealed contact with the valve seat. Opening rotational direction of the cam shaft reverses these motions.

McCormack, Kenneth J.↗

NASA NTRS2016

Numerical Evaluation of an Ejector-Enhanced Resonant Pulse Combustor with a Poppet Inlet Valve and a Converging Exhaust Nozzle

A computational investigation of a pressure-gain combustor system for gas turbine applications is presented. The system consists of a valved pulse combustor and an ejector, housed within a shroud. The study focuses on two enhancements to previous models, related to the valve and ejector components. First, a new poppet inlet valve system is investigated, replacing the previously used reed valve configuration. Secondly, a new computational approach to approximating the effects of choked turbine inlet guide vanes present immediately downstream of the Ejector-Enhanced Resonant Pulse Combustor (EERPC) is investigated. Instead of specifying a back pressure at the EERPC exit boundary (as was done in previous studies) the new model adds a converging-diverging (CD) nozzle at the exit of the EERPC. The throat area of the CD nozzle can be adjusted to obtain the desired back pressure level and total mass flow rate. The results presented indicate that the new poppet valve configuration performs nearly as well as the original reed valve system, and that the addition of the CD nozzle is an effective method to approximate the exit boundary effects of a turbine present downstream of the EERPC. Furthermore, it is shown that the more acoustically reflective boundary imposed by a nozzle as compared to a constant pressure surface does not significantly affect operation or performance.

Computational Fluid Dynamics (CFD↗

NASA NTRS2017

Europa Propulsion Valve Seat Material Testing

The Europa mission and spacecraft design presented unique challenges for selection of valve seat materials that met the fluid compatibility requirements, and combined fluid compatibility and high radiation exposure level requirements. The Europa spacecraft pressurization system valves will be exposed to fully saturated propellant vapor for the duration of the mission. The effects of Nitrogen Tetroxide (NTO) and Monomethylhydrazine (MMH) propellant vapors on heritage valve seat materials, such as Vespel SP-1 and Polychlorotrifluoroethylene (PCTFE), were evaluated to determine if an alternate material is required. In liquid system applications, Teflon is the only available compatible valve seat material. Radiation exposure data for Teflon in an air or vacuum environment has been previously documented. Radiation exposure data for Teflon in an oxidizer environment such as NTO, was not available, and it was unknown whether the effects would be similar to those on air-exposed samples. Material testing was conducted by Marshall Space Flight Center (MSFC) and White Sands Test Facility (WSTF) to determine the effects of propellant vapor on heritage seat materials for pressurization valve applications, and the effects of combined radiation and NTO propellant exposure on Teflon. The results indicated that changes in heritage pressurization valve seat materials' properties rendered them unsuitable for the Europa application. The combined radiation and NTO exposure testing of Teflon produced results equivalent to combined radiation and air exposure results.

Addona, Brad M.↗

NASA NTRS2018

A Strain Gauge Monitor (SGM) for Continuous Valve Gape Measurements In Bivalve Molluscs in Response to Laboratory Induced Diel-Cycling Hypoxia and pH

An inexpensive, laboratory-based, strain gauge valve gape monitor (SGM) was developed to monitor the valve gape behavior of bivalve molluscs in response to diel-cycling hypoxia. A Wheatstone bridge was connected to strain gauges that were attached to the shells of oysters (Crassostrea virginica). The recorded signals allowed for the opening and closing of the bivalves to be recorded continuously over two-day periods of experimentally-induced diel-cycling hypoxia and diel-cycling changes in pH. Here, we describe a protocol for developing an inexpensive strain gauge monitor and describe, in an example laboratory experiment, how we used it to measure the valve gape behavior of Eastern oysters (C. virginica), in response to diel-cycling hypoxia and cyclical changes in pH. Valve gape was measured on oysters subjected to cyclical severe hypoxic (0.6 mg/L) dissolved oxygen conditions with and without cyclical changes in pH, cyclical mild hypoxic (1.7 mg/L) conditions and normoxic (7.3 mg/L) conditions. We demonstrate that when oysters encounter repeated diel cycles, they rapidly close their shells in response to severe hypoxia and close with a time lag to mild hypoxia. When normoxia is restored, they rapidly open again. Oysters did not respond to cyclical pH conditions superimposed on diel cycling severe hypoxia. At reduced oxygen conditions, more than one third of the oysters closed simultaneously. We demonstrate that oysters respond to diel-cycling hypoxia, which must be considered when assessing the behavior of bivalves to dissolved oxygen. The valve SGM can be used to assess responses of bivalve molluscs to changes in dissolved oxygen or contaminants. Sealing techniques to better seal the valve gape strain gauges from sea water need further improvement to increase the longevity of the sensors.

Porter, Elka T.↗

NASA NTRSDate not supplied

Space Suit Portable Life Support System Thermal Control Valve Ball Design

A Thermal Control Valve (TCV) has been in development for the Exploration Extravehicular Mobility Unit Portable Life Support System (xEMU PLSS). The xEMU PLSS TCV controls flow going to the liquid cooling and ventilation garment that the crew member wears during extra-vehicular activity to expel waste heat. A previous TCV version with a linear actuator and diverter valve has been tested to attempt to control the flow accurately. The previous valve has a non-linear flow response relative to valve position and has struggled to meet the setpoints desired for precise thermal control. While many diverter valve design variations have been attempted, all previous designs have had difficulty meeting set points. Additionally, high precision machining is required to create a metal-on-metal seal which has its own drawbacks and does not always meet requirements for internal leakage. This metal seal also requires stalling a linear actuator to load the seal in compression or tension which has caused sticking failures when stalled. A new approach and design for a TCV has been developed which uses a rotational ball to control flow and has demonstrated a much more precise and linear flow control. The design functions like a two-way ball valve with two Teflon seats that cradle and compress the ball for sealing. The ball outlet has a unique geometric design to create a set-able orifice like hole which is more predictable at controlling flow. Additionally, the Teflon seat performs much better for preventing internal leakage than the metal seal and prevents sticking by having a large range in which it is sealed without having to stall the actuator. This paper will review a new proposed xEMU PLSS TCV ball design and compare it with previous iterations of the design.

Ryan Ogilvie↗

NASA NTRSDate not supplied

Space Suit Portable Life Support System Thermal Control Valve Ball Design

Ryan Ogilvie↗

DOE OSTI2024

Vacuum insulated glazing, valve, flexible seal, and method for making vacuum insulated glazing

A vacuum insulated glazing includes first and second spaced apart glass panes having perimeter portions defining a vacuum space between the glass panes. A vacuum valve is positioned at the perimeter portions of the glass panes and includes a valve body extending between the perimeter portions of the glass panes, and having first and second ends and a fluid conduit extending from the first end to the second end of the valve body and in fluid communication with the vacuum space. A one-way valve in the fluid conduit permits fluid flow from the vacuum space, and prevents fluid flow into the vacuum space. A suction fitting is provided for connecting the valve body to a suction device. An end seal between the perimeter portions of the glass panes is provided for hermetically sealing the vacuum space. A valve for a VIG and a method of making a VIG are also disclosed.

Bhandari, Mahabir↗

NASA NTRS1996

Design Enhancement and Improved Post-Actuation Test Method for a 1/4 inch Normally Closed Pyro Valve

The NASA/JPL Cassini mission to Saturn will launch in October, 1997 and arrive at Saturn in the year 2004 with a 4 year mission to orbit the planet. The main propulsion thrust vector and attitude control for the spacecraft is supplied by the Cassini Propulsion Module Subsystem (C-PMS). This system will use numerous ordnance-actuated, normally-closed (NC) pyro valves to perform mission critical tasks over the 11 year mean mission duration (NMD). The proper operation of this NC valve requires it to isolate fluid flow until commanded open. Once open, the valve must allow an unobstructed flow path and seal internally to prevent leakage external to the valve. This paper documents a design evolution to a qualified, Viking heritage design with improvements in design details that control external leakage to levels that support the planetary mission of this spacecraft. In addition, it addresses an improved post-actuation leak test technique, used to better detect gas leakage past the valve's primary metal-to-metal internal seal.

Cassini↗

NASA NTRS2016

Regolith and Environment Science and Oxygen and Lunar Volatile Extraction (RESOLVE): Lunar Advanced Volatile Analysis (LAVA) Integration and Testing - Evaluation of Lee Valve

The Resource Prospector (RP) mission with the Regolith and Environment Science and Oxygen and Lunar Volatile Extraction (RESOLVE) payload will prospect for water within the lunar regolith and provide a proof of concept for In-Situ Resource Utilization (ISRU) techniques, which could be used on future lunar and Martian missions. One system within the RESOLVE payload is the Lunar Advanced Volatiles Analysis (LAVA) subsystem, which consists of a Fluid Sub System (FSS) that transports volatiles to the Gas Chromatograph-Mass Spectrometer (GC-MS) instrument. In order for the FSS to transport precise and accurate amounts of volatiles to the GC-MS instrumentation, high performance valves are used within the system. The focus of this investigation is to evaluate the redesigned Lee valve. Further work is needed to continue to evaluate the Lee valve. Initial data shows that the valve could meet our requirements however further work is required to raise the TRL to an acceptable level to be included in the flight design of the system. At this time the risk is too high to change our baseline design to include these non-latching Lee solenoid valves.

Regolith↗

NASA NTRS1966

Segmented ball valve is easy to open and close

Segmented ball valve and flowmeter in the same spherical housing provide a valve that will handle large fluid volume without bulkiness and weight of blade valves or conventional ball valves. The valve is easily opened or closed and the flowmeter remains stationary, so errors are eliminated.

Prono, E.↗

NASA NTRS1972

Long-life, space-maintainable nuclear stage regulators and shutoff valves

The six most promising valve, regulator, and remote coupling concepts, representing the more radical designs from twenty concepts generated, were investigated. Of the three valves, one has no moving parts because shutoff sealing is accomplished by an electromagnetic field which ionized the flowing fluid. Another valve uses liquid metal to obtain sealing. In the third valve, high sealing forces are generated by heating and expanding trapped hydrogen. The pressure regulator is an electronically controlled, electromechanically operated, single state valve. Its complexity is in electronic circuitry, and the design results in less weight, increased reliability and performance flexibility, and multipurpose application. The two remote couplings feature the minimization of weight and mechanical complexity. One concept uses a low melting temperature metal alloy which is injected into the joint cavity; upon solidification, the alloy provides a seal and a structural joint. The second concept is based on the differential thermal expansion of the coupling mating parts. At thermal equilibrium there is a predetermined interference between the parts, and sealing is achieved by interference loading.

Source record↗

NASA NTRS1972

Contamination avoidance devices for poppet type shutoff valves

The technology required to provide acceptable contamination damage avoidance characteristics for poppet type shutoff valves is discussed. Evaluation of the contamination avoidance characteristics of the basic 1T32095 propellant shutoff valve, the cycle life performance of these valves in an uncontaminated environment, and the effectiveness of various auxiliary contamination avoidance devices when used in conjunction with these poppet type valves are included. In addition, a secondary objective is to evaluate two methods of monitoring the performance of the test valves during actual operations using acoustical monitoring instrumentation.

Endicott, D. L.↗

NASA NTRS1974

Explosive-actuated valve design concept that eliminates blow-by

A method of evaluating the normally open normally closed, explosive actuated valves that were selected for use in the trajectory correction propulsion subsystem of the Thermoelectric Outer Planet Spacecraft (TOPS) program is presented. The design philosophy which determined the requirements for highly reliable valves that could provide the performance capability during long duration (10 year) missions to the outer planets is discussed. The techniques that were used to fabricate the valves and manifold ten valves into an assembly with the capability of five propellant-flow initiation/isolation sequences are described. The test program, which was conducted to verify valve design requirements, is outlined and the more significant results are shown.

Hagler, R., Jr.↗

NASA NTRS1975

Line Fluid Actuated Valve Development Program

The feasibility of a line-fluid actuated valve design for potential application as a propellant-control valve on the space shuttle was examined. Design and analysis studies of two prototype valve units were conducted and demonstrated performance is reported. It was shown that the line-fluid actuated valve concept offers distinct weight and electrical advantages over alternate valve concepts. Summaries of projected performance and design goals are also included.

Lynch, R. A.↗

NASA NTRS1971

Space shuttle main engine definition (phase B). Volume 5: Valves and interconnects

The steady state thermodynamic cycle balance of the single preburner staged combustion engine, coupled with dynamic transient analyses, dictated in detail the location and requirements for each valve defined in this volume. Valve configuration selections were influenced by overall engine and vehicle system weight and failure mode determinations. Modulating valve actuators are external to the valve and are line replaceable. Development and satisfactory demonstration of a high pressure dynamic shaft seal has made this configuration practical. Pneumatic motor driven actuators that use engine pumped hydrogen gas as the working fluid are used. The helium control system is proposed as a module containing a cluster of solenoid actuated valves. The separable couplings and flanges are designed to assure minimum leakage with minimum coupling weight. The deflection of the seal surface in the flange is defined by finite element analysis that has been confirmed with test data. The seal design proposed has passed preliminary pressure cycling and thermal cycling tests.

Schultz, D. F.↗

NASA NTRS1975

Actuation and system design and evaluation OMS engine shutoff valve, Volume 1

A technology program was conducted to identify and verify the optimum valve and actuation system concept for the Space Shuttle Orbit Maneuvering System engine. Of major importance to the valve and actuation system selection was the ten-year, 100-mission, 10,000-cycle life requirement, while maintaining high reliability, low leakage, and low weight. Valve and actuation system concepts were comparatively evaluated against past valve failure reports and potential failure modes due to the shuttle mission profile to aid in the selection of the most optimum concept for design, manufacture and verification testing. Two valve concepts were considered during the preliminary design stage; i.e., the moving seat and lifting ball. Two actuation systems were manufactured and tested. Test results demonstrate the viability of a lifting ball concept as well as the applicability of an ac motor actuation system to best meet the requirements of the shuttle mission.

Dunn, V. B.↗