Turbine research package for research and development of high performance axial flow turbine-compressor Final report
Turbine research package for research and development of high performance axial flow turbine compressor
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Turbine research package for research and development of high performance axial flow turbine compressor
Feasibility of electron beam welding for repairing cracked compressor blades
Downstream stator contribution to interaction noise of single-stage axial flow compressor
Compressor research package to provide aerodynamic performance data for Brayton-cycle axial flow turbomachinery
Axial-flow medium aspect ratio compressor rotor blade rows designed to evaluate use of blade camberline shape to minimize blade element losses at high transonic speed
Design of compressor end, stator interface, and stator pivot seals for advanced air breathing engines
Axial flow compressor study to increase pressure ratio and reduce overall length
Prediction theory for effect of shear flows on outlet angle in axial compressor cascades, taking into account effects of secondary flow, Bernoolli surface rotation and spanwise flow displacement
Transmission buffer overflow prevention in telemetry data compressors using adaptive queueing control system
The carpet-plotting technique is presented in this paper as a more useful and concise method of summarizing cascade data on the NACA 65-series compressor blades given in NACA Technical Note 3916. Carpet plots included permit the selection of the blade camber and the design angle of attack required to fulfill a design vector diagram. Other carpet plots provide means for the prediction of off-design turning angles. Also presented are carpet plots of an isentropic pressure-rise coefficient as a entering Mach number.
A two-dimensional low-speed porous-wall cascade tunnel investigation has been conducted to establish the performance of the NACA 65-series compressor blade sections over the useful range of inlet angle, solidity, and section camber. Design points for optimum high-speed operation are presented. The loading limitation is determined for some conditions. Trends of section operating range with increasing section camber are determined for the four inlet angles tested.
The vibration characteristics of a group of axial-flow compressor blades of similar geometry were investigated. Empirical-mode constants were determined for the first three bending and torsional modes. A comparison of experimentally determined frequencies of a second group of blades with frequencies computed using these mode constants showed that the computed values were correct within 10 percent. The approximate limiting ratios of depth to chord and length to chord below which these constants could not be used to compute the natural frequencies were also found experimentally.
A complete stage of an axial-flow compressor was designed and built to investigate the possibility of obtaining a high pressure ratio with an acceptable efficiency through the use of the optimum combination of high blade loading and high relative inlet Mach number. Over-all stage performance was investigated over a range of flows at equivalent tip speeds of 418 to 836 feet per second. At design speed (836 ft/sec), a peak total-pressure ration of 1.445 was obtained with an adiabatic efficiency of 0.89. For design angle of attack at the mean radius, a total-pressure ratio of 1.392 was obtained.
A 30-inch tip-diameter axial-flow compressor stage was investigated with and without rotor to determine individual blade-row performance, interblade-row effects, and outer-wall boundary-layer conditions. Velocity gradients at guide-vane outlet without rotor approximated design assumptions, when the measured variation of leaving angle was considered. With rotor in operation, Mach number and rotor-blade effects changed flow distribution leaving guide vanes and invalidated design assumption of radial equilibrium. Rotor-blade performance correlated interpolated two-dimensional results within 2 degrees, although tip stall was indicated in experimental and not two-dimensional results. Boundary-displacement thickness was less than 1.0 and 1.5 percent of passage height after guide vanes and after rotor, respectively, but increased rapidly after rotor when tip stall occurred.
As a portion of an over-all performance investigation of the prototype J47D (RX-1) turbojet engine, performance of the compressor, combustor, and turbine components has been determined in the Lewis altitude wind tunnel over a range of altitude from 5000 to 55,000 feet and at flight Mach numbers from 0.19 to 0.92. Investigations were conducted with the engine operating on an electronic control schedule and slow with a two-lever control system by which fuel flow and exhaust-nozzle area could be controlled separately. Two combustor configurations were investigated.
A typical inlet axial-flow compressor inlet stage, which was designed on the basis of constant total enthalpy with symmetrical velocity diagram at all radii, was investigated. At a tip speed of 1126 feet per second, a peak pressure ratio of 1.28 was obtained at an efficiency of 0.76. At a tip speed, the highest practical flow was 28 pounds per second per square foot frontal area with an efficiency of 0.78. Data for a rotor relative inlet Mach number range of from 0.5 to 0.875 indicates that the critical value for any stage radial element is approximately 0.80 for the stage investigated.
Comparative cascade tests of the NGTE (National Gas Turbine Establishment of Great Britain) 10C4/30C50 and NACA 65-(12)10 axial flow compressor blade sections were conducted in a 5-inch low-speed cascade tunnel at the Langley Laboratory at air-inlet angles of 30 degrees, 45 degrees, and 60 degrees and a solidity of 1.0 by using the porous-wall technique. These NACA data for the NGTE 10C4/30C50 section were also compared with data from NGTE design charts for the same section. British and NACA incompressible cascade force-analysis equations are included.
A method was devised for estimating the incompressible-flow pressure distribution over compressor blade sections at design angle of attack. The theoretical incremental velocities due to camber and thickness of the section as an isolated airfoil are assumed proportional to the average passage velocity and are modified by empirically determined interference factors. Comparisons were made between estimated and test pressure distributions of NACA 65-series sections for typical conditions. Good agreement was obtained.