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Investigation of First Stage of Two-Stage Turbine Designed for Free-Vortex Flow

Description: Note presenting an experimental investigation of the first stage of a two-stage turbine designed for free-vortex flow. The results of the investigation showed that highest adiabatic efficiency was attained when the turbine was operating near the design total-pressure ratio. Results regarding power and efficiency, weight rate of gas flow through the turbine, weight-flow distribution at stator-cascade outlets, stator and rotor flow angles at mean radii, radial distribution of flow angle, radial distribution of the rotor-outlet flow angle, radial distribution of the total pressures at the stator-cascade outlet, and radial distribution of rotor-outlet pressure are provided.
Date: June 1950
Creator: Englert, G. W. & Ross, A. O.
Partner: UNT Libraries Government Documents Department

Design and Experimental Investigation of Light-Weight Bases for Air-Cooled Turbine Rotor Blades

Description: Memorandum presenting an investigation of the problem of air-cooled turbine rotor-blade weight reduction for aircraft gas turbines as part of the NACA turbine-cooling research program. A bulb-root-type blade-base design was achieved which utilized forming and brazing techniques in its manufacture and was combined with an axial-flow turbojet engine aerodynamic profile. Results regarding the sheet-metal bulb-root-type air-cooled base designs, air-cooled pinned-type base design, and some weight reduction considerations are provided.
Date: July 2, 1954
Creator: Freche, John C. & McKinnon, Roy A.
Partner: UNT Libraries Government Documents Department

Experimental Investigation of Stage Performance of J71 Three-Stage Turbine

Description: "An experimental investigation of the stage performance of the J71 three-stage turbine at design speed and pressure ratio was conducted as part of a program involving research on the design and operational characteristics of high-work-output multistage axial-flow turbines. The investigation indicated that the over-all work output of the turbine based on temperature measurements at design speed and pressure ratio was 95 percent of the design value, with the greatest loss in work output and efficiency occurring in the first stage. Choking in the second-stage stator over most of the pressure ratios investigated prevented the attainment of design first-stage work output and also prevented any increase in work output of the first stage with increasing over-all pressure ratio at design speed" (p. 1).
Date: December 20, 1954
Creator: Forrette, Robert E.
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

Correlation of turbine-blade-element losses based on wake momentum thickness with diffusion parameter for a series of subsonic turbine blades in two-dimensional cascade and for four transonic turbine rotors

Description: Report presenting an analysis of losses occurring in a series of subsonic turbine blades in a low-speed two-dimensional cascade and in a related series of four transonic rotors. Results regarding the two-dimensional cascade loss correlations, transonic turbine loss correlations, effect of unsteady flows, and mixing of stator wakes are provided.
Date: April 21, 1955
Creator: Wong, Robert Y. & Stewart, Warner L.
Partner: UNT Libraries Government Documents Department

Effect of rotor leading-edge sweepback on performance of a transonic turbine

Description: Report presenting an experimental investigation to determine the effect of rotor leading-edge sweepback on the aerodynamic performance of a transonic turbine. Using an unmodified stator with the modified rotor resulted in large incidence angles at the rotor mean and tip sections.
Date: April 29, 1955
Creator: Stewart, Warner L. & Wong, Robert Y.
Partner: UNT Libraries Government Documents Department

Investigation of two-stage air-cooled turbine suitable for flight at Mach number of 2.5 1: Velocity-diagram study

Description: Report presenting a two-stage air-cooled turbine configuration and its velocity diagrams for use in the design of blade shapes for a set of engine conditions suitable for flight at Mach number 2.5. The method used to determine the velocity diagrams was one in which the turbine frontal areas and rotor hub inlet and outlet velocities were minimized by varying the hub-tip ratio, turbine- to compressor-tip-diameter ratio, and the work split between the first and second stages.
Date: October 22, 1956
Creator: Miser, James W. & Stewart, Warner L.
Partner: UNT Libraries Government Documents Department

Investigation of turbines suitable for use in a turbojet engine with high compressor ratio and low compressor-tip speed 5: experimental performance of two-stage turbine with downstream stator

Description: An experimental investigation of a highly loaded two-stage turbine with a downstream stator revealed that (1) at equivalent design work and speed the brake internal efficiency was 0.81 and the maximum efficiency obtained was 0.85, and (2) the downstream stator left very little energy in the form of tangential velocity in the gas and, in general, performed well with 0.78 recovery being obtained at equivalent design work and speed.
Date: October 21, 1951
Creator: Davison, Elmer H.; Petrash, Donald A. & Schum, Harold J.
Partner: UNT Libraries Government Documents Department

Investigation of turbines suitable for use in a turbojet engine with high compressor pressure ratio and low compressor-tip speed 8: Internal flow conditions of a two-stage turbine with a downstream stator

Description: Report presenting an investigation of a two-stage turbine with a downstream stator to determine the interstage flow conditions of the turbine. Results regarding stage efficiency and work output, first-stage performance, second-stage performance, and downstream-stator performance are provided.
Date: November 13, 1957
Creator: Petrash, Donald A.; Davison, Elmer H. & Schum, Harold J.
Partner: UNT Libraries Government Documents Department

Investigation of turbines suitable for use in a turbojet engine with high compressor pressure ratio and low compressor-tip speed 4: effect of increasing blade speed on velocity diagrams of turbine for engine operation at constant rotative speed

Description: Report presenting the use of a simplified method of analysis in order to estimate the turbine blade-tip speed required to design satisfactory two-stage turbines. The investigation allows for certain conditions for optimal two-stage turbine design to be determined.
Date: November 24, 1952
Creator: Davison, Elmer H. & English, Robert E.
Partner: UNT Libraries Government Documents Department

Investigation of turbines suitable for use in a turbojet engine with high compressor pressure ratio and low compressor-tip speed 1: turbine-design requirements for several engine operating conditions

Description: In order to insure satisfactory turbine performance under five turbojet-engine operating conditions, turbine design requirements were determined for the following operating conditions: take-off, maximum thrust at altitude, altitude cruising at rated rotative speed, altitude cruising with maximum-thrust exhaust nozzle area, and engine acceleration at 80 percent equivalent design rotative speed. If cruising is to be at rated engine speed, both cruising and take-off should be considered in turbine design. Design requirements for the other conditions are nearly identical. Without compressor-exit bleed, a turbine cannot accelerate this compressor at 80 percent of rated speed; with 28.6-percent bleed, the design requirements are within those for take-off.
Date: March 4, 1952
Creator: English, Robert E.; Silvern, David H. & Davison, Elmer H.
Partner: UNT Libraries Government Documents Department

Component performance investigation of L71 experimental turbine 10: effect of first-stator adjustment; internal flow conditions of J71-97 turbine with 132-percent-design stator area

Description: Report presenting an investigation of the changes in the internal flow conditions resulting from adjusting the first-stator throat area of the J71 experimental three-stage turbine. The results of interstage flow measurements obtained from a radial survey investigation conducted on the turbine when equipped with a first-stage stator with the throat area increased to 132 percent of the design area and operated at a single predetermined turbine match point are also provided.
Date: January 16, 1958
Creator: Petrash, Donald A.; Schum, Harold J. & Davison, Elmer H.
Partner: UNT Libraries Government Documents Department

Component performance investigation of J71 experimental turbine 1: Over-all performance with 97-percent-design stator areas

Description: From Summary: "The over-all component performance characteristics of a J71 experimental three-stage turbine with 97 percent design stator areas were determined over a range of speed and pressure ratio at inlet-air conditions of approximately 35 inches of mercury absolute and 700 degrees R. The turbine break internal efficiency at design operating conditions was 0.877; the maximum efficiency of 0.886 occurred at a pressure ratio of 4.0 at 120 percent of design equivalent rotor speed. In general, the turbine yielded a wide range of efficient operation, permitting flexibility in the choice of different modes of engine operation."
Date: April 11, 1956
Creator: Schum, Harold J. & Davison, Elmer H.
Partner: UNT Libraries Government Documents Department

Investigation of turbines suitable for use in a turbojet engine with high compressor pressure ratio and low compressor-tip speed 3: velocity-diagram study of two-stage and downstream-stator turbines for engine operation at constant rotative speed

Description: Report presenting the use of a simplified method of analysis in order to relate the turbine operations for take-off and cruise at rotative speed. This allows turbine velocity diagrams to consider both take-off and cruising operation. Results regarding the two-stage turbine design and the downstream-stator turbine design are provided.
Date: November 21, 1952
Creator: English, Robert E. & Davison, Elmer H.
Partner: UNT Libraries Government Documents Department

Investigation of turbines suitable for use in a turbojet engine with high compressor pressure ratio and low compressor tip-speed 2: velocity-diagram study of turbine for engine operation with constant exhaust-nozzle area

Description: Report presenting an investigation of whether or not a two-stage turbine with the frontal area no larger than the compressor frontal area could be satisfactorily designed to drive a particular compressor under take-off conditions. The low blade-tip speed, high work, and high air flow per unit of frontal area of the compressor make it critical that a two-stage turbine is designed to drive it. Results regarding the effect of work division, effect of variation in cone angle, and effects of radial variations on velocity diagrams are provided.
Date: June 19, 1952
Creator: Davison, Elmer H. & English, Robert E.
Partner: UNT Libraries Government Documents Department

Visualization of rotor tip secondary flows with blade tip air discharge and suction in a low-speed turbine

Description: Smoke was used to visualize outer-wall secondary flows in a low-speed turbine utilizing rotor tip air discharge and suction. Photographs as well as visual observations of the effect of tip air discharge and suction were made by independently varying the direction and quantity of the tip air discharge and suction, and varying tip clearance, and main-stream air speed. In addition, the cross-sectional area of the hollow blade discharge opening was varied for the case of tip air discharge.
Date: August 17, 1956
Creator: Kofskey, Milton G. & Allen, Hubert W.
Partner: UNT Libraries Government Documents Department