Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “kW”

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 415 records · Page 23
All sourcesNASA NTRSDOE OSTI
NASA NTRS1982

Experience and Assessment of the DOE/NASA Mod-1 2000 Kw Wind Turbine Generator at Boone, North Carolina

The Mod 1 program objectives are defined. The Mod 1 wind turbine is described. In addition to the steel blade operated on the wind turbine, a composite blade was designed and manufactured. During the early phase of the manufacturing cycle of Mod 1A configuration was designed that identified concepts such as partial span control, a soft tower, and upwind teetered rotors that were incorporated in second and third generation industry designs. The Mod 1 electrical system performed as designed, with voltage flicker characteristics within acceptable utility limits.

Collins, J. L.↗
NASA NTRS1984

Preliminary design of a 10-kW thermophotovoltaic system for space applications

A very high degree of reflection of sub-bandgap energy photons from the cell back to the emitter was found to be crucial in achieving high efficiencies for a TPV system. Results show that small increases in reflectance above 0.85 lead to progressively larger increases in cell efficiency. In general, for a required power output, the radiator area, emitter temperature, emitter material and cell temperature may be chosen to satisfy various external constraints. The results can then be used to determine the optimum cell material and its operating temperature.

Piszczor, M. F., Jr.↗
NASA NTRS1982

A high efficiency 3 kW switchmode battery charger

This paper discusses the design approach and status of a high-efficiency switchmode battery charger designed to charge a 108 V battery from the 115 Vac line. The charger contains a transformer isolated boost chopper operating at 20 kHz. The boost inductor current is programmed to follow the ac line voltage such that high power factor operation and low line distortion are obtained.

Latos, T. S.↗
NASA NTRS1982

New component development for multi-100 kW low-cost solar array applications

Studies of the cost and performance of flexible arrays have shown that the most dramatic reductions in the $/Watt figure of merit are achieved by increasing performance. An examination of those properties that contribute to array performance indicated areas where radical changes in current design practice and philosophy would result in significant cost and performance impacts. To take advantage of the predicted cost reductions, modules were fabricated and tested that had ultra-thin superstrates as a load carrying member and large area dielectric wraparound (DWA), gridded back surface and copper contacted solar cells.

Pack, G. J.↗
NASA NTRS1984

Thermal management considerations for 100 kW(e) In-Core Thermionic Space Nuclear Power System

The general thermal management approach for the SP-100 In-Core Thermionic Space Nuclear Power System is presented. Thermal advantages and design features of the heat transport subsystem are addressed, including the selection of parameters, heat transport fluid, and materials. Pumping considerations, thermal insulation requirements, and radiator design are discussed, and the impacts of system scaling to higher power levels are projected.

Van Hagan, T. H.↗
NASA NTRS1984

Preliminary design of a 10 kW thermophotovoltaic system for space applications

A very high degree of reflection of sub-bandgap energy photons from the cell back to the emitter was found to be crucial in achieving high efficiencies for a TPV system. Results show that small increases in reflectance above 0.85 lead to progressively larger increases in cell efficiency. In general, for a required power output, the radiator area, emitter temperature, emitter material and cell temperature may be chosen to satisfy various external constraints. The results can then be used to determine the optimum cell material and its operating temperature.

Piszczor, M. F., Jr.↗
NASA NTRS1985

Test results of a 40 kW Stirling engine and comparison with the NASA-Lewis computer code predictions

A Stirling engine was tested without auxiliaries at NASA-Lewis. Three different regenerator configurations were tested with hydrogen. The test objectives were (1) to obtain steady-state and dynamic engine data, including indicated power, for validation of an existing computer model for this engine; and (2) to evaluate structurally the use of silicon carbide regenerators. This paper presents comparisons of the measured brake performance, indicated mean effective pressure, and cyclic pressure variations with those predicted by the code. The measured data tended to be lower than the computer code predictions. The silicon carbide foam regenerators appear to be structurally suitable, but the foam matrix tested severely reduced performance.

Allen, D.↗
NASA NTRS1987

Ion accelerator system mounting design and operating characteristics for a 5 kW 30-cm xenon ion engine

Results from a series of experiments to determine the effect of accelerator grid mount geometry on the performance of the J-series ion optics assembly are described. Three mounting schemes, two flexible and one rigid, are compared for their relative ion extraction capability over a range of total accelerating voltages. The largest ion beam current, for the maximum total voltage investigated, is shown to occur using one of the flexible grid mounting geometries. However, at lower total voltages and reduced engine input power levels, the original rigid J-series ion optics accelerator grid mounts result in marginally better grid system performance at the same cold interelectrode gap.

Aston, Graeme↗
NASA NTRS1988

Test results of a 40-kW Stirling engine and comparison with the NASA Lewis computer code predictions

A Stirling engine was tested without auxiliaries at Nasa-Lewis. Three different regenerator configurations were tested with hydrogen. The test objectives were: (1) to obtain steady-state and dynamic engine data, including indicated power, for validation of an existing computer model for this engine; and (2) to evaluate structurally the use of silicon carbide regenerators. This paper presents comparisons of the measured brake performance, indicated mean effective pressure, and cyclic pressure variations from those predicted by the code. The silicon carbide foam generators appear to be structurally suitable, but the foam matrix showed severely reduced performance.

Allen, David J.↗
NASA NTRS1988

Minimizing the total harmonic distortion for a 3 kW, 20 kHz ac to dc converter using SPICE

This paper describes the SPICE model of a transformer-rectified-filter (TRF) circuit and the Micro-CAP (Microcomputer Circuit Analysis Program) model and their application. The models were used to develop an actual circuit with reduced input current THD. The SPICE analysis consistently predicted the THD improvements in actual circuits as various designs were attempted. In an effort to predict and verify load regulation, the incorporation of saturable inductor models significantly improved the fidelity of the TRF circuit output voltage.

Lollar, Louis F.↗
NASA NTRS1989

The 10-100 kW submillimeter gyrotron

High frequency high harmonic gyrotrons; cyclotron autoresonance maser (CARM); CARM amplifier schematics; MIT electron gun; and baseline design for the 140 GHz CARM amplifier are briefly reviewed. This presentation is represented by viewgraphs only.

Spira, S.↗
NASA NTRS1991

Status of the advanced Stirling conversion system project for 25 kW dish Stirling applications

Heat engines were evaluated for terrestrial Solar Distributed Heat Receivers. The Stirling engine was identified as one of the most promising heat engines for terrestrial applications. Technology development is also conducted for Stirling convertors directed toward a dynamic power source for space applications. Space power requirements include high reliability with very long life, low vibration, and high system efficiency. The free-piston Stirling engine has the potential for future high power space conversion systems, either nuclear or solar powered. Although both applications appear to be quite different, their requirements complement each other.

Shaltens, Richard K.↗
NASA NTRS1991

Calorimetric output power measurements on a CW 20 kW 7.16 GHz microwave transmitter

A calorimetric measurement technique developed for NASA's Deep Space Network (DSN) transmitters that does not require data on the coolant's thermal parameters is described. Calibration of the measurement system is achieved by measuring the DC input power to the klystron and relating coolant temperature increases to this known power dissipation. Agreement between calorimetric and electrical measurements of total system power was good, the difference being less than 2 percent. The operation of the system was not greatly affected by the composition of the coolant, which was varied from pure water to 40 percent ethylene glycol by mass. Good accuracy was also shown at output power levels, which varied over a 3.6:1 range.

Perez, Raul M.↗
NASA NTRS1992

Scaling of 100 kW class applied-field MPD thrusters

Three cylindrical applied-field magnetoplasmadynamic thrusters were tested with argon propellant over a broad range of operating conditions to establish empirical scaling laws for thruster performance. Argon flow rates, discharge currents, and applied-field strengths were varied between 0.025 and 0.14 g/s, 750 to 2000 A, and 0.034 to 0.20 T, respectively. The results showed that the thrust reached over five times the self-field value, and that thrust increased linearly with the product of discharge current and applied-field strength, and quadratically with the anode radius. While increasing the propellant flow rate increased the thrust, it did not affect the rate of thrust increase with applied-field strength, and, at low propellant flow rates, the self-field thrust approached 30 percent of the measured thrust. The voltage increased linearly with applied-field strength but was insensitive to the discharge current. The rate of voltage increase with applied-field strength was strongly dependent on anode radius. Thruster efficiency increased monotonically with applied-field strength and propellant flow rate.

Myers, Roger M.↗
NASA NTRS1992

Ammonia arcjet engine behavior in a cyclic endurance test at 10 kW

The behavior of a 30 kWe-class ammonia arcjet operated at 10 kWe during the 707 successful cycles of an endurance test is described. The propellant flow rate was 0.170 g/s, and the measured performance was about 630 s specific impulse at an efficiency of 0.34. Data obtained indicate that the terminal voltage increased over the first 300 cycles, and then remained approximately constant for the remainder of the test, which suggests that the cathode eroded initially and then reached a stable geometry. No major changes were observed in thruster performance. The test was terminated by a series of external arcs.

Polk, J. E.↗
NASA NTRS1992

Scaling of 100 kW class applied-field MPD thrusters

Three cylindrical applied-field magnetoplasmadynamic thrusters were tested with argon propellant over a broad range of operating conditions to establish empirical scaling laws for thruster performance. Argon flow rates, discharge currents, and applied-field strengths were varied between 0.025 and 0.14 g/s, 750 to 2000 A, and 0.034 to 0.20T, respectively. The results showed that the thrust reached over five times the self-field value, and that thrust increased linearly with the product of discharge current and applied-field strength and quadratically with the anode radius. While increasing the propellant flow rate increased the thrust, it did not affect the rate of thrust increase with applied-field strength, and at low propellant flow rates the self-field thrust approached 30 percent of the measured thrust. The voltage increased linearly with applied-field strength but was insensitive to the discharge current. The rate of voltage increase with applied-field strength dependent on anode radius. Thruster efficiency increased monotonically with applied-field strength and propellant flow rate. Peak thruster efficiencies were insensitive to changes in anode radius. Electrode power loss and thruster efficiency measurements showed that while the electrode losses decreased with increasing anode radius the plasma losses increased. The opposite behaviors of electrode and plasma losses demonstrates the need to identify ways of independently controlling the thruster loss mechanisms.

Myers, Roger M.↗