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Combustion instability in an acid-heptane rocket with a pressurized-gas propellant pumping system

Description: Report presenting results of experimental measurements of low-frequency combustion instability of a 300-pound-thrust acid-heptane rocket engine as compared with the trends predicted by an analysis of combustion instability in a rocket engine. Results regarding the chugging frequency, combustion time delay, effect of rocket combustion-chamber characteristic length, effect of throttling, effect of injection velocity, effect of oxidant-fuel ratio, variation of chugging frequency with amplitude of chamber pressure fluctuations, and evaluation of the analysis are provided.
Date: May 1953
Creator: Tischler, Adelbert O. & Bellman, Donald R.
Partner: UNT Libraries Government Documents Department

Some screeching-combustion characteristics of a transpiration-cooled afterburner having a porous wall of wire cloth

Description: Report presenting an investigation of the screeching characteristics of two flame-holder configurations in a full-scale transpiration-cooled afterburner. The investigation indicated that a porous wall of wire cloth may be effective in eliminating or reducing the tendency to screech in some high-performance afterburners, but further testing is required. Results regarding the diametrical V-gutter, single-ring V-gutter, and durability of wire cloth are provided.
Date: November 29, 1954
Creator: Koffel, William K.; Harp, James L., Jr. & Bryant, Lively
Partner: UNT Libraries Government Documents Department

Effects of air-fuel spray and flame formation in a compression-ignition engine

Description: "High-speed motion pictures were taken at the rate of 2,500 frames per second of the fuel spray and flame formation in the combustion chamber of the NACA combustion apparatus. The compression ratio was 13.2 and the speed 1,500 revolutions per minute. An optical indicator was used to record the time-pressure relationship in the combustion chamber. The air-fuel ratio was varied from 10.4 to 365. The results showed that as the air-fuel ratio was increased definite stratification of the charge occurred in the combustion chamber even though moderate air flow existed. The results also showed the rate of vapor diffusion to be relatively slow" (p. 119).
Date: August 26, 1935
Creator: Rothrock, A. M. & Waldron, C. D.
Partner: UNT Libraries Government Documents Department

A Study of Combustion in a Flowing Gas

Description: Note presenting the results of a preliminary study of combustion in flowing gases and apparatus for obtaining high rates of heat release per unit volume of combustion space are described. Tests were made over a wide range of fuel-air ratios, inlet-mixture velocities, and electrical heat inputs, using propane gas as the fuel. Results indicate that the greater the surface-volume ratio, or the greater the amount of heat addible to the gas stream, the greater the inlet-mixture velocity at which appreciable combustion can be obtained.
Date: April 1946
Creator: Gilbert, Mitchell; Haddock, Gordon & Metzler, Allen
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

Analysis of spark-ignition engine knock as seen in photographs taken at 200,000 frames per second

Description: Report discussing a motion picture of the development of knock in a spark-ignition engine, which consists of 20 photographs taken at intervals of 5 microseconds, or at a rate of 200,000 photographs per second, with an equivalent wide-open exposure time of 6.4 microseconds for each photograph.
Date: 1946~
Creator: Miller, Cearcy D.; Olsen, H. Lowell; Logan, Walter O., Jr. & Osterstrom, Gordon E.
Partner: UNT Libraries Government Documents Department

Experimental Behavior of Pentaborane-Air Combustion Products During Expansion in a Convergent Divergent Nozzle

Description: In order to evaluate the post combustion behavior of boric oxide, pentaborane-air mixtures, burned to completion at a combustor pressure of 3 atmospheres, were expanded through a 7.1-inch-long convergent-divergent nozzle having a 4-inch-diameter throat and an exit-to-throat area ratio of 1.68. The experimentally determined thrust performance was in good agreement with the ideal equilibrium performance at stagnation temperatures of 3300 deg R and lower. The boric oxide vapor at the combustor exit required about 400 F deg supercooling before any condensed phase was observed. For a given thrust, fuel consumption was as much as 20 percent greater than predicted from vapor-pressure data for combustor outlet temperatures i n the vicinity of 3600 deg R. A similar result could be expected in full-scale engines, since the test combustor provided an unusually long dwell time and a highly turbulent environment. During the expansion process, the vapor (when present) did not condense to the extent predicted for an equilibrium expansion process. Moreover, condensation was observed only i n the form of small, abrupt phase changes i n the subsonic flow near the throat. Friction, due to liquid boric oxide films on the nozzle surfaces, was negligible when the surface temperature was above 800 F.
Date: February 18, 1958
Creator: Branstetter, J. R. & Setze, P. C.
Partner: UNT Libraries Government Documents Department

Tests of Run-of-Mine and Briquetted Coal in a Locomotive Boiler

Description: From Object of Tests: "The primary object of the tests was to study the relative performances of the two types of briquets and of the coal, with reference to efficiency, tendency to smoke, and the ease with which steam could be kept up, when each of the three varieties of fuel was burned at several rates of combustion. Many secondary objects were in mind, the data concerning which are discussed under "Effect of varying rates of combustion," pages 20-27."
Date: 1911
Creator: Ray, Walter T. & Kreisinger, Henry
Partner: UNT Libraries Government Documents Department

An Investigation of Powdered Coal as Fuel for Power-Plant Boilers: Tests at Oneida Street Power Station, Milwaukee, Wisconsin

Description: From Introduction: "This bulletin presents the results of 36 tests made on a 468-horse-power Edge Moor boiler fired with pulverized coal at the Oneida Street Station of the Milwaukee Electric Railway & Light Co., Milwaukee, Wis."
Date: 1923
Creator: Kreisinger, Henry; Blizard, John; Augustine, C. E. & Cross, B. J.
Partner: UNT Libraries Government Documents Department

Addition of heat to a compressible fluid in motion

Description: From Introduction: "The purpose of this report is to summarize, without extended proofs, the results of a study of a simplified model of nonadiabiatic, compressible fluid flow, both subsonic and supersonic, and to state these results in a form that will make them immediately useful in providing a theoretical background for current technical problems of high-speed combustion.
Date: February 1945
Creator: Hicks, Bruce L
Partner: UNT Libraries Government Documents Department

Experimental Study of Ignition by Hot Spot in Internal Combustion Engines

Description: "In order to carry out the contemplated study, it was first necessary to provide hot spots in the combustion chamber, which could be measured and whose temperature could be changed. It seemed difficult to realize both conditions working solely on the temperature of the cooling water in a way so as to produce hot spots on the cylinder wall capable of provoking autoignition. Moreover, in the majority of practical cases, autoignition is produced by the spark plug, one of the least cooled parts in the engine. The first procedure therefore did not resemble that which most generally occurs in actual engine operation" (p. 1).
Date: August 1938
Creator: Serruys, Max
Partner: UNT Libraries Government Documents Department

Some Factors Affecting Combustion in an Internal-Combustion Engine

Description: "An investigation of the combustion of gasoline, safety, and diesel fuels was made in the NACA combustion apparatus under conditions of temperature that permitted ignition by spark with direct fuel injection, in spite of the compression ratio of 12.7 employed. The influence of such variables as injection advance angle, jacket temperature, engine speed, and spark position was studied. The most pronounced effect was that an increase in the injection advance angle (beyond a certain minimum value) caused a decrease in the extent and rate of combustion. In almost all cases combustion improved with increased temperature" (p. 125).
Date: September 11, 1934
Creator: Rothrock, A. M. & Cohn, Mildred
Partner: UNT Libraries Government Documents Department

Effect of inlet-air parameters on combustion limit and flame length in 8-inch-diameter ram-jet combustion chamber

Description: Report presenting an investigation with a ram-jet combustion chamber to determine the effect of fuel-air ratio and the inlet-air parameters of pressure, temperature, and velocity on combustion limit, combustion efficiency, and flame length.
Date: July 22, 1948
Creator: Cervenka, A. J. & Miller, R. C.
Partner: UNT Libraries Government Documents Department

Combustion Velocity of Benzine-Benzol-Air Mixtures in High-Speed Internal-Combustion Engines

Description: "The present paper describes a device whereby rapid flame movement within an internal-combustion engine cylinder may be recorded and determined. By the aid of a simple cylindrical contact and an oscillograph the rate of combustion within the cylinder of an airplane engine during its normal operation may be measured for gas intake velocities of from 30 to 35 m/s and for velocities within the cylinder of from 20 to 25 m/s. With it the influence of mixture ratios, of turbulence, of compression ratio and kind of fuel on combustion velocity may be determined" (p. 1).
Date: April 1932
Creator: Schnauffer, Kurt
Partner: UNT Libraries Government Documents Department

Development of Coal Combustion Sensitivity Tests for Smoke Detectors

Description: Standard smoldering and flaming combustion tests using small coal samples have been developed by the U.S. Bureau of Mines as a method to evaluate the response of a smoke detector. The tests are conducted using a standard smoke box designed and constructed according to Underwriters Laboratories. The tests provide a standard, easily reproducible smoke characteristic for smoldering and flaming coal combustion, based upon a comparison of the smoke optical density and the response of a standard ionization chamber to the smoke. With these standard tests, the range of threshold limits for the response of a smoke detector and the detector's reliability can be evaluated for nearly identical smoke visibility and smoke physical characteristics. The detector's threshold response limits and reliability need to be well defined prior to the instrument's use as part of a mine fire warning system for improved mine safety.
Date: 1995
Creator: Edwards, John C. & Morrow, Gerald S.
Partner: UNT Libraries Government Documents Department