Endurance Evaluation of Sintered, Porous, Strut-Supported Turbine Blades made by Federal-Mogul-Bower-Bearings, Incorporated, under Bureau of Aeronautics Contract NOas 55-124-C

Endurance Evaluation of Sintered, Porous, Strut-Supported Turbine Blades made by Federal-Mogul-Bower-Bearings, Incorporated, under Bureau of Aeronautics Contract NOas 55-124-C

Date: November 26, 1957
Creator: Hickel, Robert O.
Description: Four strut-supported, transpiration-cooled turbine blades were investigated experimentally in a turbojet engine. The blade shells were fabricated by the mold-sintering method with spherical stainless-steel powder. Two blades were investigated in order to evolve suitable capping methods for the blade tip. Two other blades were used to evaluate the durability of the porous-shell material. The blades were investigated at a turbine-tip speed of 1305 feet per second, an average turbine-inlet temperature of about 1670 F, and at a porous-shell temperature limited to a maximum of approximately 1040 F.
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An Analysis of the Full-Floating Journal Bearing

An Analysis of the Full-Floating Journal Bearing

Date: January 28, 1947
Creator: Shaw, M.C.
Description: An analysis of the operating characteristics of a full-floating bearing - a bearing in which a floating sleeve is located between the journal and bearing surfaces - is presented together with charts - from which the performance of such bearings may be predicted. Examples are presented to illustrate the use of these charts and a limited number of experiments conducted upon a glass full-floating bearing to verify some results of the analysis are reported. The floating sleeve can operate over a wide range of speeds for a given shaft speed, the exact value depending principally upon the ratio of clearances and upon the ratio of radii of the bearing. Lower operating temperatures at high rotative speeds are to be expected by using a full-floating bearing. This lower operating temperature would be obtained at the expense of the load-carrying capacity of the bearing if, for comparison, the clearances remain the same in both bearings. A full-floating bearing having the same load capacity as a conventional journal bearing may be designed if decreased clearances are allowable.
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Performance of Single-Stage Turbine of Mark 25 Torpedo Power Plant with Two Special Nozzles, 1, Efficiency with 0.45-inch Rotor Blades

Performance of Single-Stage Turbine of Mark 25 Torpedo Power Plant with Two Special Nozzles, 1, Efficiency with 0.45-inch Rotor Blades

Date: May 4, 1949
Creator: Schum, Harold J.
Description: An investigation was made of the first-stage turbine of a Mark 25 torpedo power plant to determine the performance of the unity with two nozzle configurations and a special rotor having 0.45-inch blades instead of the standard length of 0.40 inch. Both nozzles had smaller passages than the nozzles of similar shape that were previously investigated. The performance of the nozzle-blade combinations is evaluated in terms of brake, rotor, and blade efficiency as functions of blade-jet speed ratio for three pressure ratios. Over the range of speeds and pressure ratios investigated, the efficiency with the nozzle having rectangular passages (J) was higher than that with a nozzle having circular passages (K). The difference in blade efficiencies varied from less than 0.010 at the lower blade-jet speed ratios for the three pressure ratios investigated to 0.030 at a pressure ratio of 8 and a blade-jet speed ratio of 0.295. The efficiencies with these tow nozzles were generally lower than those obtained with nozzles previously reported in combination with the 0.45-inch blades.
Contributing Partner: UNT Libraries Government Documents Department
Permeability and Strength Measurements on Sintered, Porous, Hollow Turbine Blades Made by the American Electro Metal Corporation under Office of Naval Research Contract N-ONR-295 (01)

Permeability and Strength Measurements on Sintered, Porous, Hollow Turbine Blades Made by the American Electro Metal Corporation under Office of Naval Research Contract N-ONR-295 (01)

Date: September 17, 1954
Creator: Richards, Hadley T.
Description: An experimental investigation was made to determine the permeability and strength characteristics of a number of sintered, porous, hollow turbine rotor blades and to determine the effectiveness of the blade fabrication method on permeability control. The test blades were fabricated by the American Electro Metal Corporation under a contract with the Office of Naval Research, Department of the Navy, and were submitted to the NACA for testing. Of the 22 test blades submitted, ten were sintered but not coined, five were sintered and coined, and seven were sintered and not coined but contained perforated reinforcements integral with the blade shells. Representative samples of each group of blades were tested. Large variations in permeability in both chordwise and spanwise directions were found. Local deviations as large as 155 to -85 percent from prescribed values were found in chordwise permeability. Only one blade, an uncoined one, had a chordwise permeability variations which reasonably approached that specified. Even for this blade, local deviations exceeded 10 percent. Spanwise permeability, specified to be held constant, varied as much as 50 percent from root to tip for both an uncoined and a coined blade. Previous NACA analyses have shown that in order to maintain proper control ...
Contributing Partner: UNT Libraries Government Documents Department
Vibration Survey of Blades in 19XB Axial-Flow Compressor, 2, Dynamic Investigation

Vibration Survey of Blades in 19XB Axial-Flow Compressor, 2, Dynamic Investigation

Date: April 9, 1947
Creator: Meyer, Andre J., Jr.
Description: Strain-gage measurements were taken under operating conditions from blades of various stages of the 19XB axial-flow compressor in an effort to determine the reason for failures in the seventh and tenth stages. First bending-mode vibrations were detected in the first five stages of the compressor caused by each integral multiple of rotor speed from three through ten. Lead-wire failures in the last five stages resulted in incomplete data. The dynamic-vibration frequencies at various rotor speeds were compared with statically measured frequencies analytically corrected for the influence of centrifugal force. Large increases in vibration ani~litude with increased pressure ratio were observed. During surging operation, blade vibrations were not present. The effects of pressure ratio and surge indicate the existence of aerodynamic excitation as the cause of the blade vibrations.
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Investigations on Experimental Impellers for Axial Blowers

Investigations on Experimental Impellers for Axial Blowers

Date: April 1, 1947
Creator: Encke, W.
Description: A selection of measurements obtained on experimental impellers for axial blowers will be reported. In addition to characteristic curves plotted for low and for high peripheral velocities, proportions and blade sections for six different blower models and remarks on the design of blowers will be presented.
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Investigation of Turbine of Mark 25 Torpedo Power Plant with Five Nozzle Designs

Investigation of Turbine of Mark 25 Torpedo Power Plant with Five Nozzle Designs

Date: October 8, 1947
Creator: Hoyt, Jack W.
Description: Efficiency investigations were made on the two-stage turbine from a Mark 25 aerial torpedo to determine the performance of the unit with five different turbine nozzles. The output of the turbine blades was computed by analyzing the windage and mechanical-friction losses of the unit. A method was developed for measuring the change in turbine clearances with changed operating conditions. The turbine was found to be most efficient with a cast nozzle having a sharp-edged inlet to the nine nozzle ports.
Contributing Partner: UNT Libraries Government Documents Department
Experimental Investigation of a Model of a Two-Stage Turboblower

Experimental Investigation of a Model of a Two-Stage Turboblower

Date: April 1, 1943
Creator: Dovjik, s.
Description: In the present paper an investigation is made of two stages of a multistage turboblower having a vaneless diffuser behind the impeller and guide vanes at the inlet to the nest stage. The method employed was that of investigating the performance of the successive elements of the blower (the impeller, vaneless diffuser, ets.) whereby the kinematics of the flow through the blower could be followed and the pressure at the different points computed. The character of the flow and the physical significance of the loss coefficients could thereby be determined so as to secure the best agreement of the computed with the actual performance of the blower. Since the tests were carried out for various delivery volumes, the dependence of the coefficients on a number of factors (angle of attack, velocities, etc.) could be obtained. The distribution of the losses that occur during the transformation of dynamic pressure at the impeller exit into static pressure could be found and likewise the range within which the friction coefficient varies in the vaneless diffuser. With the aid of factors having a certain physical significance, the centrifugal blower could be computed on the basis of a more or less schematical consideration of the ...
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Determination of the Stress Concentration Factor of a Stepped Shaft Stressed in Torsion by Means of Precision Strain Gages

Determination of the Stress Concentration Factor of a Stepped Shaft Stressed in Torsion by Means of Precision Strain Gages

Date: September 1, 1947
Creator: Weigand, A.
Description: The stress distribution in stepped shafts stressed in torsion is determined by means of the electric precision strain gage the stress concentration factor is ascertained from the measurements. It is shown that the test values always are slightly lower than the values resulting from an approximate formula.
Contributing Partner: UNT Libraries Government Documents Department
Measurement of Oil-Film Pressures in Journal Bearings under Constant and Variable Loads

Measurement of Oil-Film Pressures in Journal Bearings under Constant and Variable Loads

Date: November 1, 1949
Creator: Buske, A.
Description: In a study of journal bearings, the measurement of the oil-film strength produces some significant information. A new instrument is described by means of which the pressure of the oil film in bearings (under constant or alternating load) can be measured and recorded. With this device, the pressure distribution in the lubricating film of a bearing bushing was measured (under different operating conditions on a journal bearing) in the pulsator-bearing-testing machine. These tests are described and discussed in the present report.
Contributing Partner: UNT Libraries Government Documents Department
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