2,590 Matching Results

Search Results

Advanced search parameters have been applied.

Chemical Action of Halogenated Agents in Fire Extinguishing

Description: From Summary: "The action of halogenated agents in preventing flame propagation in fuel-air mixtures in laboratory tests is discussed in terms of a possible chemical mechanism. The mechanism chosen is that of chain-breaking reactions between agent and active particles (hydrogen and oxygen atoms and hydroxyl radicsls). Data from the literature on the flammability peaks of n-heptane agent-air mixtures are treated. Ratings of agent effectiveness in terms of the fuel equivalent of the agent, based on both fuel and agent concentrations at the peak, are proposed as preferable to ratings in terms of agent concentration alone."
Date: September 1955
Creator: Belles, Frank E.
Partner: UNT Libraries Government Documents Department

Interferometer corrections and measurements of laminar boundary layers in supersonic stream

Description: Report presenting an investigation of the laminar boundary layer on a flat plate in a supersonic stream by means of a Zehnder-Mach interferometer and a total-pressure probe. Results regarding the velocity and density profiles, skin friction, and recovery factor are provided.
Date: June 1950
Creator: Blue, Robert E.
Partner: UNT Libraries Government Documents Department

Method of designing cascade blades with prescribed velocity distributions in compressible potential flows

Description: By use of the assumption that the pressure-volume relation is linear, a solution to the problem of designing a cascade for a given turning and with a prescribed velocity distribution along the blade in a potential flow of a compressible perfect fluid was obtained by a method of correspondence between potential flows of compressible and incompressible fluids. The designing of an isolated airfoil with a prescribed velocity distribution along the airfoil is considered as a special case of cascade. If the prescribed velocity distribution is not theoretically attainable, the method provides a means of modifying the distribution so as to obtain a physically significant blade shape. Numerical examples are included.
Date: October 1, 1949
Creator: Costello, George R.
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

Performance of a blunt-lip side inlet with ramp bleed, bypass, and a long constant-area duct ahead of the engine : Mach number 0.66 and 1.5 to 2.1

Description: Unsteady shock-induced separation of the ramp boundary layer was reduced and stabilized more effectively by external perforations than by external or internal slots. At Mach 2.0 peak total-pressure recovery was increased from 0.802 to 0.89 and stable mass-flow range was increased 185 percent over that for the solid ramp. Peak pressure recovery occurred just before instability. The 7 and one-third-diameter duct ahead of the engine reduced large total-pressure distortions but was not as successful for small distortions as obtained with throat bleed. By removing boundary-layer air the bypass nearly recovered the total-pressure loss due to the long duct.
Date: December 28, 1956
Creator: Allen, John L.
Partner: UNT Libraries Government Documents Department

Preliminary investigation of effect on performance of dividing conical-spike nose inlets into halves at Mach numbers 1.5 to 2.0

Description: Inserting a splitter plate in the subsonic diffuser caused a pressure-recovery loss of about 1 percent for an inlet with a long nearly constant-area throat section. The loss was due to the increased surface area. Another inlet, which had a comparatively rapid area increase immediately after the throat, experienced pressure-recovery losses of 5 and 6 percent at Mach numbers of 1.8 and 2.0, respectively, and about 1 percent at Mach 1.5.
Date: December 19, 1955
Creator: Allen, John L.
Partner: UNT Libraries Government Documents Department

Effects of internal corner fillets on pressure recovery: Mass flow characteristics of scoop-type conical supersonic inlets

Description: Report presenting an investigation in the 8- by 6-foot supersonic tunnel at a range of free-stream Mach numbers at zero angle of attack to determine the effects of internal corner fillets on the pressure recovery characteristics of twin-scoop conical-type inlets utilizing boundary layer removal and mounted on the RM-10 body. Without boundary layer removal, the use of fillets resulted in substantial improvements in pressure recoveries and near critical mass flows up to a certain Mach number.
Date: December 8, 1952
Creator: Valerino, Alfred S.
Partner: UNT Libraries Government Documents Department

Performance characteristics at Mach numbers to 2.0 of various types of side inlets mounted on fuselage of proposed supersonic airplane 1: two-dimensional compression-ramp inlets with semicircular cowls

Description: Report presenting an experimental investigation to determine the performance of twin-scoop side inlets located on the fuselage of a proposed aircraft in a region of large boundary-layer thickness. Inlet configurations with subsonic and supersonic cowlings which utilized two-dimensional compression ramps and ram-type scoops for boundary-layer-removal systems were investigated at several Mach number ranges. Results regarding supersonic Mach number range, angle of attack, subsonic Mach number, and static conditions are provided.
Date: July 16, 1952
Creator: Valerino, Alfred S.
Partner: UNT Libraries Government Documents Department

Performance of supersonic ramp-type side inlet with combinations of fuselage and inlet throat boundary-layer removal

Description: Report presenting an experimental investigation to evaluate combinations of fuselage and inlet throat boundary-layer removal for a ramp-type side inlet in the 8- by 6-foot supersonic wind tunnel at Mach numbers 1.5, 1.8, and 2.0. Optimum combinations of fuselage and inlet throat boundary-layer removal showed gains in available thrust from 3 to 10 percent over the case of no inlet throat bleed. Results regarding variations of diffuser total-pressure distortion, recovery and external drag coefficients, and net gains in available thrust are provided.
Date: April 25, 1956
Creator: Campbell, Robert C.
Partner: UNT Libraries Government Documents Department

Performance of an Inlet Having a Variable-angle Two-dimensional Compression Surface and a Fixed-geometry Subsonic Diffuser for Application to Reduced Engine Rotative Speeds- Mach Numbers 0.66, 1.5, 1.7, and 2.0

Description: Report presenting the performance of a two-dimensional side inlet with a technique of varying compression-surface angle while retaining a fixed-geometry diffuser at several Mach numbers and zero angle of attack. A 12 degree compression ramp was faired into the diffuser contour in this conventional manner. Results regarding the inlet flow field, application to reduced engine speeds, and a inlet performance with a sudden expansion in the diffuser are provided.
Date: January 30, 1958
Creator: Allen, John L.
Partner: UNT Libraries Government Documents Department

Performance of mixed-flow impeller, model MFI-1B, with diffuser vanes at equivalent impeller speeds from 1100 to 1700 feet per second

Description: Report presenting an investigation of the performance characteristics of a mixed-flow impeller (Model MFI-1B) in combination with a vaned diffuser. The results indicated that the peak pressure ratio and maximum efficiency were not being obtained at overdesign speeds because of premature surge. Increasing inlet angle at the leading edge of the vanes improved the pressure ratio and efficiency at overdesign speeds with little to no effect on underdesign speeds.
Date: June 16, 1954
Creator: Osborn, Walter M.
Partner: UNT Libraries Government Documents Department

Jet effects on pressure loading of all-movable horizontal stabilizer

Description: Report presenting an investigation in the 8- by 6-foot supersonic tunnel to determine the effects of a cold exhaust jet on the pressure loadings of an all-movable, 45 degree sweptback horizontal stabilizer located in a region influenced by the jet. Results indicated that at jet pressure ratios of 1 to 9, the exhaust jet did not appreciably affect the pressure loadings of the stabilizer.
Date: June 10, 1954
Creator: Valerino, Alfred S.
Partner: UNT Libraries Government Documents Department

Effect of spark repetition rate on the ignition limits of a single tubular combustor

Description: The effect of spark repitition rate on the altitude ignition limits of a single tubular (turbojet engine) combustor was investigated. An increase in sparking rate from 3 to 140 sparks per second reduced the ignition limiting combustor-inlet pressure about 2 to 4 inches of mercury for air-flow rates of 1.87 and 2.80 pounds per second per square foot.520::At 3.75 pounds pe At 3.75 pounds per second per square foot, the corresponding reduction was 4 to 12 inches of mercury. The trend was similar for both low-and high-volatility fuels and for two spark-energy levels.
Date: December 6, 1951
Creator: Foster, Hampton H.
Partner: UNT Libraries Government Documents Department

Determination of elastic stresses in gas-turbine disks

Description: A method is presented for the calculation of elastic stresses in symmetrical disks typical of those of a high-temperature gas turbine. The method is essentially a finite-difference solution of the equilibrium and compatibility equations for elastic stresses in a symmetrical disk. Account can be taken of point-to-point variations in disk thickness, in temperature, in elastic modulus, in coefficient of thermal expansion, in material density, and in Poisson's ratio. No numerical integration or trial-and-error procedures are involved and the computations can be performed in rapid and routine fashion by nontechnical computers with little engineering supervision. Checks on problems for which exact mathematical solutions are known indicate that the method yields results of high accuracy. Illustrative examples are presented to show the manner of treating solid disks, disks with central holes, and disks constructed either of a single material or two or more welded materials. The effect of shrink fitting is taken into account by a very simple device.
Date: 1947
Creator: Manson, S. S.
Partner: UNT Libraries Government Documents Department

Arrangements of jet engine and airframe for increased range

Description: Report presenting an evaluation of a number of factors affecting engine-airframe arrangements in terms of range. Appropriate equations are developed and evaluated for a range of Mach numbers, ramjet and turbojet engines at several cycle temperatures, and two airplane lift-drag ratios. Some of the factors explored include inlet locations, jet cant for lift, engine moments for trim, a combination of the three factors, and the use of boundary layer in the engine.
Date: July 26, 1957
Creator: Luidens, Roger W.
Partner: UNT Libraries Government Documents Department

Correlations of heat-transfer data and of friction data for interrupted plane fins staggered in successive rows

Description: Report presenting data from five reference reports and correlate the available heat-transfer and friction data on plane fin surfaces that are interrupted and staggered in successive rows in the fluid-flow direction. A single heat-transfer correlation equation was obtained that satisfactory represents the heat-transfer data over the entire range of conditions investigated.
Date: December 1950
Creator: Manson, S. V.
Partner: UNT Libraries Government Documents Department

Determination of average heat-transfer coefficients for a cascade of symmetrical impulse turbine blades 1: heat transfer from blades to cold air

Description: Report presenting an investigation to determine average outside surface heat-transfer coefficients for a cascade of symmetrical impulse turbine blades. Results regarding recovery factor, heat-transfer coefficients, effective gas temperature, turbine cascades, cylinders and streamline bodies, and application to rim-cooling theory are provided.
Date: November 10, 1948
Creator: Meyer, Gene L.
Partner: UNT Libraries Government Documents Department

Use of source distributions for evaluating theoretical aerodynamics of thin finite wings at supersonic speeds

Description: From Summary: "A series of publications on the source-distribution methods for evaluating the aerodynamics of thin wings at supersonic speeds is summarized, extended, and unified. Included in the first part are the deviations of: (a) the linearized partial-differential equation for unsteady flow at a substantially constant Mach number. b) The source-distribution solution for the perturbation-velocity potential that satisfies the boundary conditions of tangential flow at the surface and in the plane of the wing; and (c) the integral equation for determining the strength and the location of sources to describe the interaction effects (as represented by upwash) of the bottom and top wing surfaces through the region between the finite wing boundary and the foremost Mach wave. The second part deals with steady-state thin-wing problems. The third part of the report approximates the integral equation for unsteady upwash and includes a solution of approximate equation. Expressions are then derived to evaluate the load distributions for time-dependent finite-wing motions."
Date: June 17, 1949
Creator: Evvard, John C.
Partner: UNT Libraries Government Documents Department

Design and test of mixed-flow impellers 7: experimental results for parabolic-bladed impeller with alternate blades cut back to form splitter vanes

Description: Report presenting an experimental investigation of a modified parabolic-bladed centrifugal impeller that was altered by cutting back every other blade to form splitter vanes. It was investigated over a range of equivalent impeller tip speeds and a range of flow rates. Results regarding the overall performance characteristics, a comparison of the splitter vane impeller and the fully bladed impeller, the maximum weight flow, and static-pressure ratios are provided.
Date: March 16, 1956
Creator: Osborn, Walter M.
Partner: UNT Libraries Government Documents Department

Analytical relation for wake momentum thickness and diffusion ratio for low-speed compressor

Description: From Introduction: "The present report presents the derivation of a simple equation for blade-wake mometum thickness as a function of suction-surface diffusion ratio based on the one-dimensional boundary-layer mometum equation in conjunction with simplifying approximations."
Date: August 1958
Creator: Lieblein, Seymour
Partner: UNT Libraries Government Documents Department

Analytical investigation of the effect of water injection on supersonic turbojet-engine - inlet matching and thrust augmentation

Description: From Introduction: "In order to provide engine-inlet matching to prevent such mass flow spillage and the attendant drags, much mechanical complication has been introduced. References 1 and 2 propose employing this principle at subsonic and supersonic speeds to achieve thrust augmentation. The merits of the system for supersonic engine-inlet airflow matching, as well as thrust augmentation, appear considerable; and a comparative study with existing fixed- and variable-geometry inlets was therefore undertaken."
Date: January 1957
Creator: Beke, Andrew
Partner: UNT Libraries Government Documents Department

An analytical study of turbulent and molecular mixing in rocket combustion

Description: From Introduction: "The many physical processes which occur simultaneously in rocket combustion make the entire process extremely complex (ref. 1). The combustion chamber length required for evaporation of liquid-propellant sprays has already been studied (refs. 2, 3, and 4)."
Date: September 1958
Creator: Bittker, David A.
Partner: UNT Libraries Government Documents Department

Combustion of gaseous hydrogen at low pressures in a 35 degree sector of a 28-inch-diameter ramjet combustor

Description: Report presenting testing of gaseous hydrogen fuel burned in a connected-pipe combustor with a cross section equal to 35 degrees sector of a 28-inch diameter. Eleven shrouded fuel-injector configurations were used to obtain combustion data at specified high-altitude ramjet combustor conditions. Results regarding shroud air blockage, mixing tabs, higher equivalence-ratio burning, injector size, flameholder durability, burner length, combustion efficiency, and temperature profile are provided.
Date: April 22, 1958
Creator: Kerslake, William R.
Partner: UNT Libraries Government Documents Department

Analysis of part-speed operation for high-pressure-ratio multistage axial-flow compressors

Description: From Introduction: "For the analysis reported herein, the same hypothetical 12-stage compressor discussed in reference 6 was chosen, and the effects of inlet-stage stall characteristics and stage interactions were estimated by arbitrary adjustment of the stall characteristics and stage interactions were estimated by arbitrary adjustment of the stalled characteristics of the individual stages."
Date: December 4, 1953
Creator: Benser, William A.
Partner: UNT Libraries Government Documents Department