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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 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1994

Self-Calibrating, Variable-Flow Pumping System

Pumping system provides accurate, controlled flows of two chemical liquids mixed in spray head and react to form rigid or flexible polyurethane or polyisocyanurate foam. Compatible with currently used polyurethane-based coating materials and gas-bubble-forming agents (called "blowing agents" in industry) and expected to be compatible with materials that used in near future. Handles environmentally acceptable substitutes for chlorofluorocarbon foaming agents.

Walls, Joe T.↗
NASA NTRS1989

Convergent strand array liquid pumping system

A surface-tension liquid pumping system is provided by one or more arrays of converging solid monofilament fibers or metal wires (strands) spaced apart at an input end to gather liquid, and gathered close together at the opposite end where menisci forms between wetted strands to force liquid in the direction of convergence of the strands. The liquid pumping system is independent of gravity. It is illustrated as being used in a heat pump having a heating box to vaporize the liquid and a condensing chamber. Condensed liquid is returned by the pumping system to the heating box where it is again vaporized. A vapor tube carries the vapor to the condensing chamber. In that way, a closed system pumps heat from the heating box to the evaporating chamber and from there radiated to the atmosphere.

Collins, Earl R., Jr.↗
NASA NTRS1981

Reciprocating piston pump system with screw drive

A pump system of the reciprocating piston type is described, which facilitates direct motor drive and cylinder sealing. A threaded middle potion of the piston is engaged by a nut connected to rotate with the rotor of an electric motor, in a manner that minimizes loading on the rotor by the use of a coupling that transmits torque to the nut but permits it to shift axially and radially with respect to the rotor. The nut has a threaded hydrostatic bearing for engaging the threaded piston portion, with an oil-carrying groove in the nut being interrupted. A fluid emitting seal located at the entrance to each cylinder, can serve to center the piston within the cylinder, wash the piston, and to aid in sealing. The piston can have a long stroke to diameter ratio to minimize reciprocations and wear on valves at high pressures. The voltage applied to the motor can be reversed prior to the piston reaching the end of its stroke, to permit pressure on the piston to aid in reversing the motor.

Perkins, Gerald S.↗
NASA NTRS1981

Vacuum pumping system for spaceborne passive hydrogen masers

The ultimate utility of hydrogen masers as highly accurate clocks aboard navigation satellites depends on the feasibility of making the maser lightweight, compact, and capable of a 5 to 7 year unattended operation. A vacuum pumping system for the maser that is believed to meet these criteria was designed and fabricated. The pumping system was fabricated almost completely from 6Al-4V titanium alloy and incorporates two or four sintered zirconium carbon getter pumps with integral activation heaters. The manner in which the getter pumps were mounted to insure that they will stand both the activation and the shock of launch is illustrated. Data on the total hydrogen capacity and pumping of this system is also presented.

Wolf, S. A.↗
NASA NTRS1981

Assessment of solar-assisted gas-fired heat pump systems

As a possible application for the Goldstone Energy Project, the performance of a 10 ton heat pump unit using a hybrid solar gas energy source was evaluated in an effort to optimize the solar collector size. The heat pump system is designed to provide all the cooling and/or heating requirements of a selected office building. The system performance is to be augmented in the heating mode by utilizing the waste heat from the power cycle. A simplified system analysis is described to assess and compute interrrelationships of the engine, heat pump, and solar and building performance parameters, and to optimize the solar concentrator/building area ratio for a minimum total system cost. In addition, four alternative heating cooling systems, commonly used for building comfort, are described; their costs are compared, and are found to be less competitive with the gas solar heat pump system at the projected solar equipment costs.

Lansing, F. L.↗
NASA NTRS1973

Contamination Effects of Getter Ion and Titanium Sublimation Pumped Systems on Optical Surfaces

Previous studies have indicated that ultraclean vacuum can be produced when titanium sublimation pumps are used in conjunction with getter-ion pumps. Experiments are described in which the degrees of cleanliness of a typical getter-ion, titanium sublimation-pumped system were monitored by measuring the effects of surface contamination on the reflectance of evaporated vacuum ultraviolet mirrors. Results are presented which indicate that severe reflectance losses occurred when startup of a getter-ion pump was initiated at too high a chamber pressure. Significant reflectance losses also occurred as a result of titanium sublimation-pump operation. These data are reviewed and recommendations for improved system performance are presented.

Visentine, James T.↗
NASA NTRS1981

Low-thrust chemical propulsion system pump technology

Candidate pump and driver systems for low thrust cargo orbit transfer vehicle engines which deliver large space structures to geosynchronous equatorial orbit and beyond are evaluated. The pumps operate to 68 atmospheres (1000 psi) discharge pressure and flowrates suited to cryogenic engines using either LOX/methane or LOX/hydrogen propellants in thrust ranges from 445 to 8900 N (100 to 2000 lb F). Analysis of the various pumps and drivers indicate that the low specific speed requirement will make high fluid efficiencies difficult to achieve. As such, multiple stages are required. In addition, all pumps require inducer stages. The most attractive main pumps are the multistage centrifugal pumps.

Sabiers, R. L.↗
NASA NTRS1951

Combustion Instability in an Acid-Heptane Rocket with a Pressurized-Gas Propellant Pumping System

Results of experimental measurements of low-frequency combustion instability of a 300-pound thrust acid-heptane rocket engine were compared to the trends predicted by an analysis of combustion instability in a rocket engine with a pressurized-gas propellant pumping system. The simplified analysis, which assumes a monopropellant model, was based on the concept of a combustion the delay occurring from the moment of propellant injection to the moment of propellant combustion. This combustion time delay was experimentally measured; the experimental values were of approximately half the magnitude predicted by the analysis. The pressure-fluctuation frequency for a rocket engine with a characteristic length of 100 inches and operated at a combustion-chamber pressure of 280 pounds per square inch absolute was 38 cycles per second; the analysis indicated. a frequency of 37 cycles per second. Increasing combustion-chamber characteristic length decreased the pressure-fluctuation frequency, in conformity to the analysis. Increasing the chamber operating pressure or increasing the injector pressure drop increased the frequency. These latter two effects are contrary to the analysis; the discrepancies are attributed to the conflict between the assumptions made to simplify the analysis and the experimental conditions. Oxidant-fuel ratio had no apparent effect on the experimentally measured pressure-fluctuation frequency for acid-heptane ratios from 3.0 to 7.0. The frequencies decreased with increased amplitude of the combustion-chamber pressure variations. The analysis indicated that if the combustion time delay were sufficiently short, low-frequency combustion instability would be eliminated.

Tischler, Adelbert O.↗
NASA NTRS1990

A modified pump laser system to pump the titanium sapphire laser

As a result of the wide tunability of the titanium sapphire laser NASA has sited it to be used to perform differential absorption lidar (DIAL) measurements of H2O vapor in the upper and lower troposphere. The titanium sapphire laser can provide a spectrally narrow (0.3 to 1.0 pm), high energy (0.5 to 1.0 J) output at 727, 762, and 940 nm which are needed in the DIAL experiments. This laser performance can be obtained by addressing the line-narrowing issues in a master oscillator and the high energy requirement in a fundamental mode oscillator. By injection seeding, the single frequency property of the master oscillator can produce a line narrow high energy power oscillator. A breadboard model of the titanium sapphire laser that will ultimately be used in NASA lidar atmospheric sensing experiment is being designed. The task was to identify and solve any problem that would arise in the actual laser system. One such problem was encountered in the pump laser system. The pump laser that is designed to pump both the master oscillator and power oscillator is a Nd:YLF laser. Nd:YLF exhibits a number of properties which renders this material an attractive option to be used in the laser system. The Nd:YLF crystal is effectively athermal; it produces essentially no thermal lensing and thermally induced birefringence is generally insignificant in comparison to the material birefringence resulting from the uniaxial crystal structure. However, in application repeated fracturing of these laser rods was experience. Because Nd:YLF rods are not commercially available at the sizes needed for this application a modified pump laser system to replace the Nd:YLF laser rod was designed to include the more durable Nd:YAG laser rods. In this design, compensation for the thermal lensing effect that is introduced because of the Nd:YAG laser rods is included.

Petway, Larry B.↗
NASA NTRS1982

A proposed optical pumping system requiring no electric power

A method for optically pumping a fluid without electrical power is described. The method is based on utilizing the radiation from a metal oxidant combustion reaction that is contained within a transparent tube that is immersed in the medium to be pumped. The reaction initiation and maintenance occurs by gas dynamically induced resonance within the transparent cavity. All that is required is a supply of high pressure oxidant and metallic powder. Materials that were successfully evaluated to date include aluminum, steel, magnesium, and titanium.

Phillips, B. R.↗
NASA NTRS2022

Performance Evaluation of a Vapor-compression-cycle Based Heat Pump System for a Lunar Habitat under the Impact of Dust Deposits on the Coupled Radiators

Space exploration gains new momentum. A near goal is set by NASA to return humans to the Moon andestablish a sustainable presence on the lunar surface for more repeatable and affordable expeditions.The lunar dust is one of the dangerous environment hazard causing serious problems for explorationactivities. In this paper, in order to study the impact of lunar dust on the performance of a thermalmanagement system for a lunar habitat, a dynamical model of an active thermal control system that iscomprised of a vapor-compression cycle heat pump and a radiator loop is developed. A heat pump to liftthe heat rejection temperature is required due to high lunar daytime surface temperature. Parametricstudies on radiator size, percentage of dust coverage on the radiator, and lunar habitat location arecarried out. The results show that lunar deposits can significantly increase the power consumption ofthe thermal management system. A dust covered radiator panel results in net heat input to the heattransfer fluid during the period of strong solar irradiance, causing deteriorated performance of theradiator loop. The lunar dust contamination problem raises the requirement of redundancy design of asystem for fault tolerance. A synergetic design of a thermal management system, a power generationsystem and robotic maintenance system is proposed to achieve maximal mass cut for a whole lunarhabitat system.

Chunjian Pan↗
NASA NTRS1974

Geothermal down well pumping system

A key technical problem in the exploitation of hot water geothermal energy resources is down-well pumping to inhibit mineral precipitation, improve thermal efficiency, and enhance flow. A novel approach to this problem involves the use of a small fraction of the thermal energy of the well water to boil and super-heat a clean feedwater flow in a down-hole exchanger adjacent to the pump. This steam powers a high-speed turbine-driven pump. The exhaust steam is brought to the surface through an exhaust pipe, condensed, and recirculated. A small fraction of the high-pressure clean feedwater is diverted to lubricate the turbine pump bearings and prevent leakage of brine into the turbine-pump unit. A project demonstrating the feasibility of this approach by means of both laboratory and down-well tests is discussed.

Matthews, H. B.↗
NASA NTRS1980

Low-thrust chemical propulsion system pump technology

A study was conducted within the thrust range 450 to 9000 N (100 to 2000 pounds). Performance analyses were made on centrifugal, pitot, Barske, drag, Tesla, gear, piston, lobe, and vane pumps with liquid hydrogen, liquid methane, and liquid oxygen as propellants. Gaseous methane and hydrogen driven axial impulse turbines, vane expanders, piston expanders, and electric motors were studied as drivers. Data are presented on performance, sizes, weights, and estimated service lives and costs.

Meadville, J. W.↗