Results for “CRYOGENIC FLUID” — Page 15

NASA NTRS2024

Solid-State Thermodynamic Vent System (STVS) for Control of Cryogenic Propellants

A Solid-State Thermodynamic Vent System (STVS) is a novel Cryogenic Fluid Management (CFM) technology for spacecraft cryogenic propellant tanks that may reduce boiloff while providing greater control over the propellant condition. By exploiting the vacuum-induced cryocooling (VIC) potential of cryogen-saturated silica aerogel material, an internal STVS heat exchanger (HX) can expel some sacrificial cryogenic propellant to the vacuum of space to produce cooling within the storage tank. This cooling is transferred directly to the stored fluid, thereby reducing boiloff and increasing hold times. Testing proved the effectiveness of the concept by reducing the liquid nitrogen (LN 2 ) boiloff rate and tank pressure by roughly 70% and 77%, respectively, during a single pump-down cycle, which sacrificed around 1.8 kg of propellant.

Cryogenic Fluid↗

NASA NTRSDate not supplied

Long Duration Storage of Liquid Hydrogen via Two-Stage Active Cooling Hardware Characterization and Test Planning

The zero boil-off storage of liquid hydrogen using active cooling (cryocoolers) with a two-stage cooling approach is being investigated by NASA. In interest of advancing the technology to enable extended duration storage for the agency’s future long duration missions, NASA’s Technology Demonstration Mission Program has funded this five-year effort which includes the design, build and testing of a test article to demonstrate this concept. This paper includes discussions of the multiple Cryogenic Fluid Management technologies that were studied under NASA’s Cryogenic Propellant Storage and Transfer project, design of the test article to be demonstrated, then the planned test objectives which include characterization testing of the active cooling system, demonstration of the control system, preliminary testing with liquid nitrogen, and a complete demonstration of zero boil-off storage of liquid hydrogen. The full demonstration will be conducted in the East Test Area at NASA Marshall Space Flight Center and is currently scheduled to begin on October 1st, 2024.

Cryogenic Fluid Management↗

NASA NTRS2017

Zero-Boil-Off Tank (ZBOT) Experiment: Ground-Based Validation of Self-Pressurization and Pressure Control Two-Phase CFD Model

Integral to all phases of NASA's projected space and planetary expeditions is affordable and reliable cryogenic fluid storage for use in propellant or life support systems. Cryogen vaporization due to heat leaks into the tank from its surroundings and support structure can cause self-pressurization relieved through venting. This has led to a desire to develop innovative pressure control designs based on mixing of the bulk tank fluid together with some form of active or passive cooling to allow storage of the cryogenic fluid with zero or reduced boil-off. The Zero-Boil-Off Tank (ZBOT) Experiments are a series of small scale tank pressurization and pressure control experiments aboard the International Space Station (ISS) that use a transparent volatile simulant fluid in a transparent sealed tank to delineate various fundamental fluid flow, heat and mass transport, and phase change phenomena that control storage tank pressurization and pressure control in microgravity. The hardware for ZBOT-1 flew to ISS on the OA-7 flight in April 2017 and operations are planned to begin in September 2017, encompassing more than 90 tests. This paper presents preliminary results from ZBOT's ground-based research delineating both pressurization and pressure reduction trends in the sealed test tank. Tank self-pressurization tests are conducted under three modes: VJ heating, strip heating and simultaneous VJ and strip heating in attempt to simulate heat leaks from the environment, the support structure and both. The jet mixing pressure control studies are performed either from an elevated uniform temperature condition or from thermally stratified conditions following a self-pressurization run. Jet flow rates are varied from 2-25 cm/s spanning a range of jet Re number in laminar, transitional, and turbulent regimes and a range of Weber numbers covering no ullage penetration, partial penetration and complete ullage penetration and break-up (only in microgravity). Numerical prediction of a two-phase CFD model are compared to experimental 1g results to both validate the model and also indicate the effect of the residual non-condensable gas on evolution of pressure and temperature distributions in the tank during pressurization and pressure control.

microgravity evaporation condensatio↗

NASA NTRS1995

Fluid Film Bearing Code Development

The next generation of rocket engine turbopumps is being developed by industry through Government-directed contracts. These turbopumps will use fluid film bearings because they eliminate the life and shaft-speed limitations of rolling-element bearings, increase turbopump design flexibility, and reduce the need for turbopump overhauls and maintenance. The design of the fluid film bearings for these turbopumps, however, requires sophisticated analysis tools to model the complex physical behavior characteristic of fluid film bearings operating at high speeds with low viscosity fluids. State-of-the-art analysis and design tools are being developed at the Texas A&M University under a grant guided by the NASA Lewis Research Center. The latest version of the code, HYDROFLEXT, is a thermohydrodynamic bulk flow analysis with fluid compressibility, full inertia, and fully developed turbulence models. It can predict the static and dynamic force response of rigid and flexible pad hydrodynamic bearings and of rigid and tilting pad hydrostatic bearings. The Texas A&M code is a comprehensive analysis tool, incorporating key fluid phenomenon pertinent to bearings that operate at high speeds with low-viscosity fluids typical of those used in rocket engine turbopumps. Specifically, the energy equation was implemented into the code to enable fluid properties to vary with temperature and pressure. This is particularly important for cryogenic fluids because their properties are sensitive to temperature as well as pressure. As shown in the figure, predicted bearing mass flow rates vary significantly depending on the fluid model used. Because cryogens are semicompressible fluids and the bearing dynamic characteristics are highly sensitive to fluid compressibility, fluid compressibility effects are also modeled. The code contains fluid properties for liquid hydrogen, liquid oxygen, and liquid nitrogen as well as for water and air. Other fluids can be handled by the code provided that the user inputs information that relates the fluid transport properties to the temperature.

Source record↗

NASA NTRSDate not supplied

Axisymmetric Two-Dimensional Modeling of No Vent Filling of a Cryogenic Tank using Generalized Fluid System Simulation Program

Filling a tank with cryogenic fluid is more challenging than filling a tank with water or any other fluid that is in liquid state at atmospheric condition. Filling a tank with cryogenic fluid is a two-step process. First the tank and the transfer line mustbe chilled. Liquid cryogens start flowing into the tank only after the tank and transfer lines are chilled to the fluid saturation temperature. In normal gravity, cryogenic tanks are usually filled from the bottom at nearly atmospheric pressure. The vapor, caused by heat transfer from the warm tank walls, is allowed to vent from the top of the tank while the tank is being filled. Filling a cryogenic tank in the absence of gravity is more challenging because in a non-stratified environment liquid propellantmay not settle at the tank bottom as it does on earth. There is a strong possibility that liquid propellant may exit through the vent valve, which is typically located at the top of the tank to vent propellant vapor. There are several methodsof filling atank in space: Charge-Hold-Vent method [1], Vented-Chill / No-Vent-Fill (VCNVF)[2],and No Vent Fill with TVS assisted injector [3].This paper addressesnumerical modelingofthe No Vent Fill (NVF) processwhere a TVS (Thermodynamic Vent System) augmented injector was used with the vent valve closed during the entire filling process. NVF tests were conducted in the CRYOgenic Orbital Testbed (CRYOTE) tankat NASA/Marshall Space Flight Centerin 2018.The Generalized Fluid System Simulation Program (GFSSP), a general-purpose flow network code [4] was used to simulate the chilland fill process.

Cryogenics↗

NASA NTRS1990

Cryogenic On-Orbit Liquid Depot Storage, Acquisition, and Transfer satellite (COLD-SAT) feasibility study

The Cryogenic On-Orbit Liquid Depot Storage, Acquisition, and Transfer Satellite (COLD-SAT) is an experimental spacecraft launched from an expendable launch vehicle which is designed to investigate the systems and technologies required for efficient, effective, and reliable management of cryogenic fluid in the reduced gravity space environment. The COLD-SAT program will provide the necessary data base and provide low-g proving of fluid and thermal models of cryogenic storage, transfer, and resupply concepts and processes. A conceptual approach was developed and an overview of the results of the 24 month COLD-SAT Phase A feasibility is described which includes: (1) a definition of the technology needs and the accompanying experimental 3 month baseline mission; (2) a description of the experiment subsystem, major features and rationale for satisfaction of primary and secondary experiment requirements using liquid hydrogen as the test fluid; and (3) a presentation of the conceptual design of the COLD-SAT spacecraft subsystems which support the on-orbit experiment with emphasis on areas of greatest challenge.

Bailey, William J.↗

NASA NTRS1974

Heater-mixer for stored fluids

A fluid storage vessel for containing cryogenic fluids is described. The storage vessel contains an auxiliary chamber which is connected to the main container by a jet nozzle. The wall of the auxiliary vessel is heat cycled to produce a corresponding expansion and contraction of the fluid within the auxiliary chamber. This action causes heating and mixing of the stored fluid by means of jetting the expanded fluid to and from relative to the stored fluid contents of the vessel.

Canning, T. N.↗

NASA NTRS1993

Low-g fluid mixing - Further results from the Tank Pressure Control Experiment

The Tank Pressure Control Experiment (TPCE) made its first space flight on STS-43 in 1991. Its objective was to test the effectiveness of low-energy axial jet mixing at controlling pressures in low gravity. The experiment used refrigerant 113 at near-saturation conditions, at an 83 percent fill level, to simulate the fluid dynamics and thermodynamics of cryogenic fluids in future space applications. Results from this flight were reported previously. TPCE was again flown in space on STS-52 in 1992, this time primarily to study boiling and related thermal phenomena which will be reported elsewhere. However additional mixing and pressure control data were obtained from the reflight that supplement the data from the first flight.

Bentz, M. D.↗

NASA NTRS2009

Boiler and Pressure Balls Monopropellant Thermal Rocket Engine

The proposed technology is a rocket engine cycle utilizing as the propulsive fluid a low molecular weight, cryogenic fluid, typically liquid hydrogen, pressure driven, heated, and expelled through a nozzle to generate high velocity and high specific impulse discharge gas. The proposed technology feeds the propellant through the engine cycle without the use of a separate pressurization fluid and without the use of turbomachinery. Advantages of the proposed technology are found in those elements of state-of-the-art systems that it avoids. It does not require a separate pressurization fluid or a thick-walled primary propellant tank as is typically required for a classical pressure-fed system. Further, it does not require the acceptance of intrinsic reliability risks associated with the use of turbomachinery

Greene, William D.↗

NASA NTRS2019

High Efficiency Megawatt Machine Rotating Cryocooler Conceptual Design

Some of the challenges associated with developing electric aircraft propulsion systems include developing powertrain components that are both efficient and light-weight. In particular, electric motors must simultaneously achieve high efficiency by minimizing electrical and mechanical losses while also achieving high specific power by increasing the torque and/or speed. Normally increasing torque or speed will increase electrical and mechanical losses. The High Efficiency Megawatt Machine (HEMM) minimizes electrical losses by incorporating a superconductor to enable increased current on the rotor. And the rotor spins in a vacuum to minimize thermal and mechanical losses. Some organizations have been developing superconducting rotors for similar reasons using either cryogenic fluid transfer systems, fully immersed cryogenic cooling, and in a few cases utilized built-in cryogenic cooling on the rotor using a Brayton or Stirling system but the implementation was too large or inefficient for effective motor integration. Instead, a new approach for cryogenically cooling the superconducting rotor coil with an embedded rotating cryocooler is presented that fits completely within the rotating shaft.

Dyson, Rodger W.↗

NASA NTRS2019

High Efficiency Megawatt Machine Rotating Cryocooler Conceptual Design

Some of the challenges associated with developing electric aircraft propulsion systems include developing powertrain components that are both efficient and light-weight. In particular, electric motors must simultaneously achieve high efficiency by minimizing electrical and mechanical losses while also achieving high specific power by increasing the torque and/or speed. Normally increasing torque or speed will increase electrical and mechanical losses. The High Efficiency Megawatt Machine (HEMM) minimizes electrical losses by incorporating a superconductor to enable increased current on the rotor. And the rotor spins in a vacuum to minimize thermal and mechanical losses. Some organizations have been developing superconducting rotors for similar reasons using either cryogenic fluid transfer systems, fully immersed cryogenic cooling, and in a few cases utilized built-in cryogenic cooling on the rotor using a Brayton or Stirling system but the implementation was too large or inefficient for effective motor integration. Instead, a new approach for cryogenically cooling the superconducting rotor coil with an embedded rotating cryocooler is presented that fits completely within the rotating shaft.

Dyson, Rodger W.↗

NASA NTRS2007

Propulsion Technology Needs for Exploration

The objectives of currently planned exploration efforts, as well as those further in the future, require significant advancements in propulsion technologies. The current Lunar exploration architecture has set goals and mission objectives that necessitate the use of new systems and the extension of existing technologies beyond present applications. In the near term, the majority of these technologies are the result of a need to apply high performing cryogenic propulsion systems to long duration in-space applications. Advancement of cryogenic propulsion to these applications is crucial to provide higher performing propulsion systems that reduce the vehicle masses; enhance the safety of vehicle systems and ground operations; and provide a path for In-situ Resource Utilization (ISRU).Use of a LOX/LH2 main propulsion system for Lunar Lander Descent is a top priority because more conventional storable propellants are far from meeting the performance needs of the current architecture. While LOX/LH2 pump feed engines have been used in flight applications for many years, these engines have limited throttle capabilities. Engines that are capable of much greater throttling while still meeting high performance goals are a necessity to achieving exploration goals. Applications of LOX/CH4 propulsion to Lander ascent propulsion systems and reaction control systems are also if interest because of desirable performance and operations improvements over conventional storable systems while being more suitable for use of in-situ produced propellants. Within the current lunar architecture, use of cryogenic propulsion for the Earth Departure Stage and Lunar Lander elements also necessitate the need for advanced Cryogenic Fluid Management technologies. These technologies include long duration propellant storage/distribution, low-gravity propellant management, cryogenic couplings and disconnects, light weight composite tanks and support structure, and subsystem integration. In addition to the propulsive and fluid management system technologies described, many component level technologies are also required to enable to the success if the integrated systems. The components include, but are not limited to, variable/throttling valves, variable position actuators, leak detectors, light weight cryogenic fluid pumps, sensor technology and others. NASA, partnering with the Aerospace Industry must endeavor to develop these, and other promising propulsion technologies, to enable the implements of the country's goals in exploration of the Moon, Mars and beyond.

Brown, Thomas↗

NASA NTRSDate not supplied

Feasibility and Utility of a Cryogenic Integrated RCS

Traditional in-space propulsion systems use storable propellants, such as MMH/NTO, for applications beyond Low Earth Orbit (LEO). Modern advancements in Cryogenic Fluid Management (CFM) technologies opens the door for use of more efficient cryogenic propellants, such as LOX/LCH4 or LOX/LH2, in these long-duration missions beyond LEO. As these Main Propulsion Systems (MPS) transition to cryogenic propellants, a cryogenic solution for Reaction Control Systems (RCS) becomes attractive for several reasons. A mixed-fluid vehicle solution with cryogenic (cool) MPS and storable (warm) RCS complicates thermal management. Additionally, a vehicle with common cryogenic propellant across the MPS and RCS could take advantage of shared hardware such as tanks, thermal management equipment, and pressurization system, reducing mass and development time. The fluid system design proposed in this presentation features shared hardware, leading to the designation of Cryogenic Integrated Reaction Control System (iRCS). The iRCS design stores cryogenic propellant in the low-pressure (10’s psia) MPS tanks, creates steady high-pressure (100’s psia) flow through an electric pump (e-pump), feeds pulse-firing RCS thrusters, and returns any excess flow to the tank through a pressure control device on a recirculation line. This iRCS design is inspired by the automotive fuel-rail, where similar elevated-pressure and pulse-firing requirements are levied. This design has several inherent advantages. Because this design is pump-fed rather than pressure-fed, heavy, high-pressure propellant storage is not required. The RCS propellant can therefore be stored by increasing MPS tank volume. Furthermore, by increasing the pressure of the circulated fluid through an e-pump, the propellant quality moves further into the sub-cooled regime. Sub-cooled liquid is desirable for accurate pressure and flow control at the thruster inlet. Lastly, the iRCS allows the distribution system hardware to maintain cryogenic temperatures by slowly recirculating liquid in a low-energy “Idle Mode”. Altogether, the iRCS concept enables a more efficient cryogenic vehicle design.

Integrated Reaction Control System↗

NASA NTRS2023

Solid-State Thermodynamic Vent System for Control of Cryogenic Propellants

A Solid-State Thermodynamic Vent System (STVS) is a novel Cryogenic Fluid Management (CFM) technology for spacecraft cryogenic propellant tanks that may reduce boiloff while providing greater control over the propellent condition. By exploiting the vacuum-induced cryocooling potential of cryogen-saturated silica aerogel material, an internal STVS heat exchanger expels some sacrificial cryogenic propellant to the vacuum of space to produce cooling within the storage tank. This cooling is transferred directly to the stored fluid, thereby reducing boiloff and increasing hold times. The primary STVS project objective was to design and build a bespoke STVS heat exchanger that employed aerogel blanket material and perform a ground demonstration of the technology using liquid nitrogen (LN2) as the cryogenic propellant. This demonstration aimed to prove that an STVS can have a positive influence on the tank boiloff, shown through a reduction in mass flow rate out of the system during operation, and exercise control over the tank pressure. Testing proved the effectiveness of the concept by reducing the LN2 boiloff rate and tank pressure by roughly 70% and 77% respectively during a single pump-down cycle, which sacrificed around 1.8 kg of propellant.

Propellant Production↗

NASA NTRSDate not supplied

Cryocooler Technology Opportunities within Space Exploration

As the demands for extended space missions and sustained lunar and Martian presence grow, the need for power and mass-efficient cryogenic fluid production and storage becomes paramount. The exploration and advancement of space technologies necessitate the development of innovative cryogenic storage solutions to ensure reliable, long-term production and preservation of cryogens in space environments for propulsion, life-support, and power applications. This paper covers an analysis of the challenges posed by long-duration cryogen storage and production for in-space and surface applications for NASA’s upcoming missions, as well as highlighting cryocooler technology opportunities and gaps to encourage industry stakeholders to contribute innovative solutions to advance the field of cryogenic storage for space applications.

Cryogenic Fluid Management↗

NASA NTRSDate not supplied

Feasibility and Utility of a Cryogenic Integrated RCS

Traditional in-space propulsion systems use storable propellants, such as MMH/NTO, for applications beyond Low Earth Orbit (LEO). Modern advancements in Cryogenic Fluid Management (CFM) technologies opens the door for use of more efficient cryogenic propellants, such as LOX/LCH4 or LOX/LH2, in these long-duration missions beyond LEO. As these Main Propulsion Systems (MPS) transition to cryogenic propellants, a cryogenic solution for Reaction Control Systems (RCS) becomes attractive for several reasons. A mixed-fluid vehicle solution with cryogenic (cool) MPS and storable (warm) RCS complicates thermal management. Additionally, a vehicle with common cryogenic propellant across the MPS and RCS could take advantage of shared hardware such as tanks, thermal management equipment, and pressurization system, reducing mass and development time. The fluid system design proposed in this presentation features shared hardware, leading to the designation of Cryogenic Integrated Reaction Control System (iRCS). The iRCS design stores cryogenic propellant in the low-pressure (10’s psia) MPS tanks, creates steady high-pressure (100’s psia) flow through an electric pump (e-pump), feeds pulse-firing RCS thrusters, and returns any excess flow to the tank through a pressure control device on a recirculation line. This iRCS design is inspired by the automotive fuel-rail, where similar elevated-pressure and pulse-firing requirements are levied. This design has several inherent advantages. Because this design is pump-fed rather than pressure-fed, heavy, high-pressure propellant storage is not required. The RCS propellant can therefore be stored by increasing MPS tank volume. Furthermore, by increasing the pressure of the circulated fluid through an e-pump, the propellant quality moves further into the sub-cooled regime. Sub-cooled liquid is desirable for accurate pressure and flow control at the thruster inlet. Lastly, the iRCS allows the distribution system hardware to maintain cryogenic temperatures by slowly recirculating liquid in a low-energy “Idle Mode”. Altogether, the iRCS concept enables a more efficient cryogenic vehicle design.

Integrated↗

NASA NTRS1975

Bibliography on contaminants and solubility of organic compounds in oxygen

A compilation of a number of document citations is presented which contains information on contaminants in oxygen. Topics covered include contaminants and solubility of organic compounds in oxygen, reaction characteristics of organic compounds with oxygen, and sampling and detection limits of impurities. Each citation in the data bank contains many items of information about the document. Some of the items are title, author, abstract, corporate source, description of figures pertinent to hazards or safety, key references, and descriptors (keywords) by which the document can be retrieved. Each citation includes an evaluation of the technical contents as to being good/excellent, acceptable, or poor. The descriptors used to define the contents of the documents and subsequently used in the computerized search operations were developed for the cryogenic fluid safety by experts in the cryogenics field.

Ordin, P. M.↗

NASA NTRS1987

Advanced long term cryogenic storage systems

Long term, cryogenic fluid storage facilities will be required to support future space programs such as the space-based Orbital Transfer Vehicle (OTV), Telescopes, and Laser Systems. An orbital liquid oxygen/liquid hydrogen storage system with an initial capacity of approximately 200,000 lb will be required. The storage facility tank design must have the capability of fluid acquisition in microgravity and limit cryogen boiloff due to environmental heating. Cryogenic boiloff management features, minimizing Earth-to-orbit transportation costs, will include advanced thick multilayer insulation/integrated vapor cooled shield concepts, low conductance support structures, and refrigeration/reliquefaction systems. Contracted study efforts are under way to develop storage system designs, technology plans, test article hardware designs, and develop plans for ground/flight testing.

Brown, Norman S.↗