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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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1991

Application of an unsteady Navier-Stokes solver to transonic turbine design

This study presents a numerical evaluation of the performance of the first stage of a new-generation turbine design. The numerical method solves the two-dimensional Navier-Stokes equations using a system of patched grids. Three-dimensional effects of stream-tube contraction are also modeled. The study focuses on the effects of axial gap variation on the unsteady rotor-stator interactions and on stage performance. Results are presented for three different axial gaps. The results indicate that the unsteady interactions can be very large in this design. These interactions affect not only the stage efficiency but also substantially alter the time-averaged features of the flow. In particular, for the case of the smallest axial gap, it was found that there was an unsteady shock on the stator suction surface which spanned the gap region and impinged upon the moving rotor airfoils.

Rangwalla, Akil A.↗
NASA NTRS1951

Comparison of measured efficiencies of nine turbine designs with efficiencies predicted by two empirical methods

Empirical methods of Ainley and Kochendorfer and Nettles were used to predict performances of nine turbine designs. Measured and predicted performances were compared. Appropriate values of blade-loss parameter were determined for the method of Kochendorfer and Nettles. The measured design-point efficiencies were lower than predicted by as much as 0.09 (Ainley and 0.07 (Kochendorfer and Nettles). For the method of Kochendorfer and Nettles, appropriate values of blade-loss parameter ranged from 0.63 to 0.87 and the off-design performance was accurately predicted.

FLOW-TURBINES↗
NASA NTRS1972

Supersonic turbine design and performance.

Methods for designing supersonic stator and rotor blading corrected for boundary layer displacement thickness are summarized. Computer programs based on these methods have been reported in NASA publications. Analytical blader blading of this type are presente and design limitations resulting from consideration of flow separation and supersonic srting are discussed. In additiona summary of the experimental perormance of a single-stage turbine designed by these methods is given.

Goldman, L. J.↗
NASA NTRS1971

Supersonic turbine design and performance

Methods for designing supersonic stator and rotor blading corrected for boundary layer displacement thickness are summarized. Computer programs based on these methods have been reported in NASA publications. Analytical blade losses for blading of this type are presented and design limitations resulting from consideration of flow separation and supersonic starting are discussed. In addition, a summary of the experimental performance of a single-stage turbine designed by these methods is given.

Goldman, L. J.↗
NASA NTRS1982

Inherent uncertainties in meteorological parameters for wind turbine design

Major difficulties associated with meteorological measurments such as the inability to duplicate the experimental conditions from one day to the next are discussed. This lack of consistency is compounded by the stochastic nature of many of the meteorological variables of interest. Moreover, simple relationships derived in one location may be significantly altered by topographical or synoptic differences encountered at another. The effect of such factors is a degree of inherent uncertainty if an attempt is made to describe the atmosphere in terms of universal laws. Some of these uncertainties and their causes are examined, examples are presented and some implications for wind turbine design are suggested.

Doran, J. C.↗
NASA NTRS1972

Turbine Design and Application, Volume 1

Review of turbine technology including thermodynamics, compressible fluid mechanics, fundamental turbine concepts, and velocity diagram design

Arthur J. Glassman↗
NASA NTRS1976

A review of the Mark 48-F, 3.50 pitch diameter, 2-stage reaction turbine designed for the staged combustion cycle requirements of an advanced space engine

The Mark 48-F two-stage reaction turbine was designed as a component for an advanced space engine propellant feed system, high-pressure liquid hydrogen turbopump. The turbine total inlet temperature and total inlet pressure were designed to be 1860 R and 3420 psia, respectively. At a design speed of 95,000 rpm, the turbine will develop 2543 horsepower with LO2/LH2 working fluid. The aerothermodynamic performance of a prototype turbine assembly was evaluated with gaseous nitrogen working fluid. Turbine performance was evaluated at turbine velocity ratios ranging from 0.250 to 0.782, and turbine speeds up to 25,250 rpm. Turbine test efficiency at the design velocity ratio of 0.483 was found to be 79.5% total-to-total.

Macaluso, S. B.↗
NASA NTRS1953

Investigation of Distribution of Losses in a Conservatively Designed Turbine

A primary objective of turbine research is to obtain information that will aid in the design of gas turbines for any given application with minimum losses. As part of a program to obtain such information, flow surveys downstream of both the stator and the rotor of an experimental turbine were made in order to obtain detailed information about the flow conditions and the losses within the machine. The single-stage, low-radius-ratio turbine studied is relatively conservative in design, having low rotor-inlet relative Mach number, low turning angle, and high reaction at the rotor-root section. Surveys of the flow conditions and of the losses within the turbine are presented. The measured over-all losses are analyzed in order to approximate the magnitudes of the various components of loss. It was found that the major losses in the turbine were in the rotor near the blade extremities. The losses in the tip region were considerably greater than those near the hub. The existence of secondary flows at the exit of both the stator and the rotor was indicated by the presence of low-velocity cores near both the hub and the tip sections. Analysis of the losses by an empirical method indicated that the rotor-profile and tip-clearance losses are 31 and 9 percent of the adjusted measured total rotor loss, respectively. The remaining 60 percent loss was attributed to secondary flows.

TURBINES - AXIAL-FLOW↗
NASA NTRS1978

Cold-air performance of a tip turbine designed to drive a lift fan. 3: Effect of simulated fan leakage on turbine performance

Performance data were obtained experimentally for a 0.4 linear scale version of the LF460 lift fan turbine for a range of scroll inlet total to diffuser exit static pressure ratios at design equivalent speed with simulated fan leakage air. Tests were conducted for full and partial admission operation with three separate combinations of rotor inlet and rotor exit leakage air. Data were compared to the results obtained from previous investigations in which no leakage air was present. Results are presented in terms of mass flow, torque, and efficiency.

Haas, J. E.↗
NASA NTRS1973

Calculated performance map of a 4 1/2-stage 15.0 centimeter (5.9 inch) mean diameter turbine designed for a turbofan simulator

The overall performance of an existing high-ratio turbine is calculated analytically over a range of speed and pressure ratio in order to determine its capability for other applications. The analytical performance covers a speed range from 50 to 120 percent of design and a pressure-ratio range from 5.0 to 35.0. The turbine was designed for a 50.8 centimeter (20.0 in.) tip diameter turbofan simulator. Computed results are compared with the experimental turbine data obtained from testing three fan configurations with the turbofan simulator in air. The comparison indicates good agreement over the range of speeds and pressure ratios covered by the experimental data.

Wasserbauer, C. A.↗
NASA NTRS1988

Integration of rocket turbine design and analysis through computer graphics

An interactive approach with engineering computer graphics is used to integrate the design and analysis processes of a rocket engine turbine into a progressive and iterative design procedure. The processes are interconnected through pre- and postprocessors. The graphics are used to generate the blade profiles, their stacking, finite element generation, and analysis presentation through color graphics. Steps of the design process discussed include pitch-line design, axisymmetric hub-to-tip meridional design, and quasi-three-dimensional analysis. The viscous two- and three-dimensional analysis codes are executed after acceptable designs are achieved and estimates of initial losses are confirmed.

Hsu, Wayne↗
NASA NTRS1978

Fatigue impact on Mod-1 wind turbine design

Fatigue is a key consideration in the design of a long-life Wind Turbine Generator (WTG) system. This paper discusses the fatigue aspects of the large Mod-1 horizontal-axis WTG design starting with the characterization of the environment and proceeding through the design. Major sources of fatigue loading are discussed and methods of limiting fatigue loading are described. NASTRAN finite element models are used to determine dynamic loading and internal cyclic stresses. Recent developments in determining the allowable fatigue stress consistent with present construction codes are discussed relative to their application to WTG structural design.

Stahle, C. V., Jr.↗