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Altitude-Wind-Tunnel Investigation of a 4000-Pound-Thrust Axial-Flow Turbojet Engine, 5, Analysis of Turbine Performance

Description: From Summary: "Performance characteristics of the turbine of a 4000-pound-thrust axial-flow turbojet engine was determined in investigations of the complete engine in the NACA Cleveland altitude wind tunnel. Characteristics are presented as functions of the total-pressure ratio across the turbine and of turbine speed and gas flow corrected to sea-level conditions. Three turbine nozzles of different areas were used to determine the area that gave optimum performance. Inasmuch as tail-pipe nozzles of different diameters were investigated in combination with the standard turbine nozzle, the effect of varying discharge conditions on turbine operation could be observed."
Date: August 4, 1948
Creator: Krebs, Richard P. & Hensley, Reece V.
Partner: UNT Libraries Government Documents Department

Cooling of Gas Turbines, 2, Effectiveness of Rim Cooling of Blades

Description: An analysis is presented of rim cooling of gas-turbine blades; that is, reducing the temperature at the base of the blade (wheel rim), which cools the blade by conduction alone. Formulas for temperature and stress distributions along the blade are derived and, by the use of experimental stress-rupture data for a typical blade alloy, a relation is established between blade life (time for rupture), operating speed, and amount of rim cooling for several gas temperatures. The effect of blade parameter combining the effects of blade dimensions, blade thermal conductivity, and heat-transfer coefficient is determined. The effect of radiation on the results is approximated. The gas temperatures ranged from 1300F to 1900F and the rim temperature, from 0F to 1000F below the gas temperature. This report is concerned only with blades of uniform cross section, but the conclusions drawn are generally applicable to most modern turbine blades. For a typical rim-cooled blade, gas temperature increases are limited to about 200F for 500F of cooling of the blade base below gas temperature, and additional cooling brings progressively smaller increases. In order to obtain large increases in thermal conductivity or very large decreases in heat-transfer coefficient or blade length or necessary. The increases in gas temperature allowable with rim cooling are particularly small for turbines of large dimensions and high specific mass flows. For a given effective gas temperature, substantial increases in blade life, however, are possible with relatively small amounts of rim cooling.
Date: March 18, 1947
Creator: Wolfenstein, Lincoln; Meyer, Gene L. & McCarthy, John S.
Partner: UNT Libraries Government Documents Department

Investigation of high-temperature operation of liquid-cooled gas turbines I: turbine wheel of aluminum alloy, a high-conductivity nonstrategic material

Description: Report presenting an investigation of turbine operating temperatures as affected by liquid cooling, especially if materials of high conductivity are used, at gas temperatures up to 1925 degrees Fahrenheit. Results regarding the statio heat-transfer rig and turbine rig are provided. The investigation showed that nonstrategic material such as aluminum alloy can be used in liquid-cooled turbine wheels at high gas temperatures.
Date: July 22, 1948
Creator: Kottas, Harry & Sheflin, Bob W.
Partner: UNT Libraries Government Documents Department

Experimental Permeability Measurements on a Strut-Supported Transpiration-Cooled Turbine Blade with Stainless-Steel Shell made by the Federal-Mogul Corporation under Bureau of Aeronautics Contract N0as 51613-C

Description: A turbine blade with a porous stainless-steel shell sintered to a supporting steel strut has been fabricated for tests at the NACA by Federal-Mogul Corporation under contract from the Bureau of Aeronautics, Department of the Navy. The apparent permeability of this blade, on the average, more nearly approaches the values specified by the NAGA than did two strut-supported bronze blades in a previous investigation. Random variations of permeability in the present blade are substantialy greater than those of the bronze blades, but projected improvements in certain phases of the fabrication process are expected to reduce these variations.
Date: April 30, 1954
Creator: Richards, Hadley T.
Partner: UNT Libraries Government Documents Department

Turbine performance characteristics of a python turbine-propeller engine investigated in altitude wind tunnel

Description: Report presenting the performance of the turbine component of a Python turbine-propeller engine with four tail-pipe configurations determined over a range of altitudes, engine speeds, and fuel flows. Results regarding the corrected turbine speed, corrected turbine enthalpy drop, pressure ratio, and efficiency were established on a turbine-characteristic plot.
Date: May 1, 1951
Creator: Farley, John M. & Prince, William R.
Partner: UNT Libraries Government Documents Department

Performance of Single-Stage Turbine of Mark 25 Torpedo Power Plant with Two Nozzles and Three Rotor-Blade Designs

Description: From Summary: "A single-stage modification of the turbine from a Mark 25 torpedo power plant was investigated to determine the performance with two nozzles and three rotor-blade designs. The performance was evaluated in terms of brake, rotor, and blade efficiencies at pressure ratios of 8, 15 (design), and 20. The blade efficiencies with the two nozzles are compared with those obtained with four other nozzles previously investigated with the same three rotor-blade designs."
Date: September 9, 1949
Creator: Schum, Harold J. & Whitney, Warren J.
Partner: UNT Libraries Government Documents Department

Use of effective momentum thickness in describing turbine rotor-blade losses

Description: Report presenting a discussion of the use of an effective rotor-blade momentum thickness in describing rotor-blade loss characteristics. A derivation of the necessary equations is presented for obtaining momentum thickness for given overall turbine performance, stator performance, and rotor geometric quantities.
Date: May 14, 1956
Creator: Stewart, Warner L.; Whitney, Warren J. & Miser, James W.
Partner: UNT Libraries Government Documents Department

Vibrational modes of several hollow turbine blades and of solid turbine blade of similar aerodynamic design

Description: Experimental study to determine the vibrational modes of several hollow turbine blades and a solid turbine blade of similar aerodynamic design. Results regarding the significance of nodal patterns, vibrational modes of six blade types, and the probability of excitation in some of the blades are provided.
Date: October 3, 1949
Creator: Kemp, R. H. & Shifman, J.
Partner: UNT Libraries Government Documents Department

Effect of nozzle secondary flows on turbine performance as indicated by exit surveys of a rotor

Description: Report presenting detailed circumferential and radial surveys of total pressure and total temperature made downstream of the turbine rotor of a high-speed, high-specific-mass-flow turbine at design operating conditions. The purpose of this testing was to determine the sources and magnitudes of losses in turbines. Results regarding total pressure ratio, total-temperature-drop ratio, contours of efficiency, and location of the losses are provided.
Date: April 5, 1954
Creator: Whitney, Warren J.; Buckner, Howard A., Jr. & Monroe, Daniel E.
Partner: UNT Libraries Government Documents Department

Component and over-all performance evaluation of a J47-GE-25 turbojet engine over a range of engine-inlet Reynolds number indices

Description: Report presenting an investigation in the altitude test chamber to evaluate the performance of an axial-flow turbojet engine over a range of engine-inlet Reynolds number indices. Secondary effects of exhaust-nozzle flow coefficient, air-flow leakage, and inlet temperature should be considered before analyzing the effect of variations in engine-inlet Reynolds number index. Several minor design modifications proposed by the manufacturer did not produce any measurable improvement in engine performance.
Date: September 29, 1953
Creator: Walker, Curtis L.; Braithwaite, Willis M. & Fenn, David B.
Partner: UNT Libraries Government Documents Department

Component performance investigation of J71 experimental turbine IX: effect of first-stator adjustment;internal flow conditions of J71-97 turbine with 87-percent-design stator area

Description: From Summary: "An experimental radial-survey investigation of the J71-97 three-stage turbine equipped with a first stator having a throat area 87 percent of the design value was conducted at one turbine operating point. The first-, second-, and third-stage mass-averaged efficiencies were 0.897, 0.843, and 0.755, respectively. The corresponding over-all turbine efficiency was 0.856."
Date: April 30, 1957
Creator: Schum, Harold J.; Petrash, Donald A. & Davison, Elmer H.
Partner: UNT Libraries Government Documents Department

Component performance investigation of J71 experimental turbine: IV - Effect of first-stator adjustment; over-all performance of J71-97 turbine with 132-percent-design stator area

Description: An experimental invesitgation of the effect of increasing the first-stator area of the J71-97 experimental three-stage turbine from 97 percent of design to 132 percent revealed (1) the maximum efficiency obtained decreased from 0.891 to 0.869, (2) the choking equivalent weight flows increased by approximately 13.6 percent, and (3) at the turbine match points required to maintain the compressor at constant design equivalent conditions the turbine efficiency decreased from 0.87 to 0.86.
Date: April 17, 1956
Creator: Davison, Elmer H.; Petrash, Donald A. & Schum, Harold J.
Partner: UNT Libraries Government Documents Department

Experimental study of flow past turbine blades

Description: From Introduction: "The requirements on gas turbines for aircraft power units, namely, adequate efficiency, operation at high gas temperatures, low weight, and small dimensions, must be taken into consideration during the design of the blading. To secure good efficiency, it is necessary that the gas flow past the blades as smoothly as possible without separation. This is relatively easily obtainable in the accelerated flow of turbine blading, if the blade spacing is chosen small enough. A small blade spacing, however, is detrimental to the other requirements outlined above. Operation at high gas temperatures usually calls for blade cooling. This cooling is associated with a power input that lowers the turbine efficiency. Since the amount of heat that must be carried off for coding a blade can be influenced rather little, the gross power input for a turbine stage can be reduced by keeping the number of blades to a minimum, that is, with blades of high spacing ratio. But here also a limit is imposed, the exceeding of which is followed by separation of flow. Hence the requirement of finding blade forms on which the flow separates at rather high spacing ratios."
Date: June 1949
Creator: Eckert, E. & Vietinghoff-Scheel, K. V.
Partner: UNT Libraries Government Documents Department

Secondary flows and boundary-layer accumulations in turbine nozzles

Description: An investigation of secondary-flow loss patterns originating in three sets of turbine nozzle blade passages was conducted by means of flow-visualization studies and detailed flow measurements. For all cases, high loss values were measured in the fluid downstream of the corners formed by the suction surfaces of the blades and the shrouds, and these losses were accompanied by discharge-angle deviations from design values. Despite the size of the loss regions and angle gradients, over-all mass-average blade efficiencies were of the order of 0.99 and 0.98 and, therefore, are not a good index of blade performance.
Date: April 30, 1953
Creator: Rohlik, Harold E.; Kofskey, Milton G.; Allen, Hubert W. & Herzig, Howard Z.
Partner: UNT Libraries Government Documents Department

Performance of Single-Stage Turbine of Mark 25 Torpedo Power Plant with Two Special Nozzles, III, Efficiency with Standard Rotor Blades

Description: A Mark 25 torpedo power plant modified to operate as a single-stage turbine was investigated to determine the performance with two nozzle designs and a standard first-stage rotor having 0.40-inch blades with a 17O met-air angle. Both nozzles had smaller port cross-sectional areas than those nozzles of similar design, which were previously investigated. The performance of the two nozzles was compared on the basis of blade, rotor, and brake efficiencies as a function of blade-jet speed ratio for pressure ratios of 8, 15 (design), and 20. At pressure ratios of 15 and 20, the blade efficiency obtained with the nozzle having circular passages (K) was higher than that obtained with the nozzle having rectangular passages (J). At a pressure ratio of 8, the efficiencies obtained with the two nozzles were comparable for blade-jet speed ratios of less than 0.260. For blade-jet speed ratios exceeding this value, nozzle K yielded slightly higher efficiencies. The maximum blade efficiency of 0.569 was obtained with nozzle K at a pressure ratio of 8 and a blade-jet speed ratio of 0.295. At design speed and pressure ratio, nozzle K yielded a maximum blade efficiency of 0.534, an increase of 0.031 over that obtained with nozzle J. When the blade efficiencies of the two nozzles were compared with those of four other nozzles previously investigated, the maximum difference for the six nozzles with this rotor was 0.050. From, this comparison, no specific effect of nozzles size or shape on over-all performance was discernible.
Date: January 1, 1949
Creator: Schum, Harold J. & Whitney, Warren J.
Partner: UNT Libraries Government Documents Department

Cooling of Gas Turbines, 3, Analysis of Rotor and Blade Temperatures in Liquid-Cooled Gas Turbines

Description: A theoretical analysis of the radial temperature distribution through the rotor and constant cross sectional area blades near the coolant passages of liquid cooled gas turbines was made. The analysis was applied to obtain the rotor and blade temperatures of a specific turbine using a gas flow of 55 pounds per second, a coolant flow of 6.42 pounds per second, and an average coolant temperature of 200 degrees F. The effect of using kerosene, water, and ethylene glycol was determined. The effect of varying blade length and coolant passage lengths with water as the coolant was also determined. The effective gas temperature was varied from 2000 degrees to 5000 degrees F in each investigation.
Date: February 11, 1947
Creator: Brown, W. Byron & Livingood, John N. B.
Partner: UNT Libraries Government Documents Department

Performance evaluation of reduced-chord rotor blading as applied to J73 two-stage turbine 5: effect of inlet pressure on over-all performance at design speed and inlet temperature of 700 degrees R

Description: Report presenting an investigation of a reduced-chord multistage turbine at design speed and various turbine-inlet pressures from 12 to 40 inches of mercury absolute. At each inlet pressure, the turbine was operated over a range of overall turbine total-pressure ratios; turbine-inlet temperature was maintained at 700 degrees R. The results indicated that no appreciable effect on turbine overall performance was observed over the range of turbine-inlet total pressures investigated.
Date: July 5, 1957
Creator: Schum, Harold J.
Partner: UNT Libraries Government Documents Department

A general representation for axial-flow fans and turbines

Description: From Summary: "A general representation of fan and turbine arrangements on a single classification chart is presented which is made possible by a particular definition of the stage of an axial-flow fan or turbine. Several unconventional fan and turbine arrangements are indicated and the applications of these arrangements are discussed."
Date: June 1945
Creator: Perl, W. & Tucker, M.
Partner: UNT Libraries Government Documents Department

Aerodynamic Heat-Power Engine Operating on a Closed Cycle

Description: "Hot-air engines with dynamic compressors and turbines offer new prospects of success through utilization of units of high efficiencies and through the employment of modern materials of great strength at high temperature. Particular consideration is given to an aerodynamic prime mover operating on a closed circuit and heated externally. Increase of the pressure level of the circulating air permits a great increase of limit load of the unit. This also affords a possibility of regulation for which the internal efficiency of the unit changes but slightly. The effect of pressure and temperature losses is investigated" (p. 1).
Date: November 1942
Creator: Ackeret, J. & Keller, D. C.
Partner: UNT Libraries Government Documents Department

Flight Performance of a Jet Power Plant, 3, operating characteristics of a jet power plant as a function of altitude

Description: The performance of a jet power plant consisting of a compressor and a turbine is determined by the characteristic curves of these component parts and is controllable by the characteristics of the compressor and the turbine in relation to each other. The normal. output, overload, and throttled load of the Jet power plant are obtained on the basis of assumed straight-line characteristics.
Date: May 1951
Creator: Weinig, F.
Partner: UNT Libraries Government Documents Department

Performance evaluation of reduced-chord rotor blading as applied to J73 two-stage turbine 1: over-all performance with standard rotor blading at inlet conditions of 35 inches of mercury absolute and 700 degrees R

Description: Report presenting an investigation conducted to determine the overall performance of the J73 two-stage turbine with a standard rotor-blade configuration. The turbine operated with a maximum brake internal efficiency between 0.91 and 0.92 at an overall pressure ratio of about 3.4 and 120 percent equivalent design rotor speed. Results regarding the overall performance, variation of equivalent weight flow with overall pressure ratio, and effect of limiting blade loading are provided.
Date: July 11, 1957
Creator: Berkey, William E.; Rebeske, John J., Jr. & Forrette, Robert E.
Partner: UNT Libraries Government Documents Department

Experimental Investigation of an 0.8 Hub-Tip Radius-Ratio, Nontwisted-Rotor-Blade Turbine

Description: "An experimental investigation of a 0.8 hub-tip radius ratio, nontwisted-rotor-blade turbine designed for a stagnation-pressure ratio of 2.5 and an equivalent mean blade speed of 643 feet per second was made in a cold-air turbine with (a) nontwisted stator blades, and (b) twisted stator blades designed to maintain zero rotor-inlet incidence angles. Turbine efficiencies of the order of 0.85 at the design point were obtained with a nontwisted-rotor-blade turbine with a hub-tip radius ratio of 0.80. The turbine with the twisted stator blades gave higher efficiencies at the design point (of the order of 1.5 percentage points) than the turbine with the nontwisted stator blades" (p. 1).
Date: December 12, 1951
Creator: Silvern, David H. & Slivka, William R.
Partner: UNT Libraries Government Documents Department

Investigation of a Related Series of Turbine-Blade Profiles in Cascade

Description: From Summary: "An application of airfoil design methods was used to design series of related turbine-blade profiles to satisfy the conditions of inlet flow angle and turning angle encountered in the usual range of turbine operation. A series of blade profiles applicable to most turbine blading requirements and a secondary series with particular reference to impulse conditions were designed. Five blade sections from these series ranging in mean-line turning angles from 63 deg. to 120 deg. were tested in low-speed cascade tunnels."
Date: December 7, 1953
Creator: Dunavant, James C. & Erwin, John R.
Partner: UNT Libraries Government Documents Department