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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

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

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

Steady Nuclear Combustion in Rockets

Description: "The astrophysical theory of stationary nuclear reactions in stars is applied to the conditions that would be met in the practical engineering cases that would differ from the former, particularly with respect to the much lower combustion pressures, dimensions of the reacting volume, and burnup times. This application yields maximum rates of hear production per unit volume of reacting gas occurring at about 10(exp 8) K in the cases of reactions between the hydrogen isotopes, but yields higher rates for heavier atoms. For the former, with chamber pressures of the order of 100 atmospheres, the energy production for nuclear combustion reaches values of about 10(exp 4) kilocalories per cubic meter per second, which approaches the magnitude for the familiar chemical fuels" (p. 1).
Date: April 1957
Creator: Sänger, E.
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

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

Terascale High-Fidelity Simulations of Turbulent Combustion with Detailed Chemistry: Spray Simulations

Description: The Terascale High-Fidelity Simulations of Turbulent Combustion (TSTC) project is a multi-university collaborative effort to develop a high-fidelity turbulent reacting flow simulation capability utilizing terascale, massively parallel computer technology. The main paradigm of the approach is direct numerical simulation (DNS) featuring the highest temporal and spatial accuracy, allowing quantitative observations of the fine-scale physics found in turbulent reacting flows as well as providing a useful tool for development of sub-models needed in device-level simulations. Under this component of the TSTC program the simulation code named S3D, developed and shared with coworkers at Sandia National Laboratories, has been enhanced with new numerical algorithms and physical models to provide predictive capabilities for turbulent liquid fuel spray dynamics. Major accomplishments include improved fundamental understanding of mixing and auto-ignition in multi-phase turbulent reactant mixtures and turbulent fuel injection spray jets.
Date: April 26, 2009
Creator: Rutland, Christopher J.
Partner: UNT Libraries Government Documents Department

Combustor oscillation pressure stabilizer

Description: In accordance with the objective of the present invention, the active control of unsteady combustion induced oscillations in a combustion chamber fired by a suitable fuel and oxidizer mixture, such as a hydrocarbon fuel and air mixture, is provided by restructuring and moving the position of the main flame front and thereby increasing the transport time and displacing the pressure wave further away from the in-phase relationship with the periodic heat release. The restructuring and repositioning of the main flame are achieved by utilizing a pilot flame which is pulsed at a predetermined frequency corresponding to less than about one-half the frequency of the combustion oscillation frequency with the duration of each pulse being sufficient to produce adequate secondary thermal energy to restructure the main flame and thereby decouple the heat release from the acoustic coupling so as to lead to a reduction in the dynamic pressure amplitude. The pulsating pilot flame produces a relatively small and intermittently existing flame front in the combustion zone that is separate from the oscillating main flame front but which provides the thermal energy necessary to effectively reposition the location of the oscillating main flame front out of the region in the combustion zone where the acoustic coupling can occur with the main flame and thereby effectively altering the oscillation-causing phase relationship with the heat of combustion.
Date: December 31, 1996
Creator: Gemmen, R.S.; Richards, G.A.; Yip, M.T.J.; Robey, E.; Cully, S.R. & Addis, R.E.
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

Self-Ignition and Combustion of Gases

Description: This paper attempts to state laws for the self-ignition and combustion of gases in a comprehensive manner. The primary focus is recent investigations in which new combustion phenomena or new methods of studying them experimentally are brought out and investigations that throw new light on already known phenomena.
Date: August 1942
Creator: Sokolik, A. S.
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

Lagrangian Simulation of Combustion

Description: A Lagrangian approach for the simulation of reactive flows has been developed during the course of this project, and has been applied to a number of significant and challenging problems including the transverse jet simulations. An efficient strategy for parallel domain decomposition has also been developed to enable the implementation of the approach on massively parallel architecture. Since 2005, we focused our efforts on the development of a semi-Lagrangian treatment of diffusion, and fast and accurate Lagrangian simulation tools for multiphysics problems including combustion.
Date: May 1, 2008
Creator: Ghoniem, Ahmed F.
Partner: UNT Libraries Government Documents Department

Displacement speeds in turbulent premixed flame simulations

Description: The theory of turbulent premixed flames is based on acharacterization of the flame as a discontinuous surface propagatingthrough the fluid. The displacement speed, defined as the local speed ofthe flame front normal to itself, relative to the unburned fluid,provides one characterization of the burning velocity. In this paper, weintroduce a geometric approach to computing displacement speed anddiscuss the efficacy of the displacement speed for characterizing aturbulent flame.
Date: July 1, 2007
Creator: Day, Marcus S.; Shepherd, Ian G.; Bell, J.; Grcar, Joseph F. & Lijewski, Michael 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

Combustion of n-heptane in a shock tube and in a stirred reactor: A detailed kinetic modeling study

Description: A detailed chemical kinetic reaction mechanism is used to study the oxidation of n-heptane under several classes of conditions. Experimental results from ignition behind reflected shock waves and in a rapid compression machine were used to develop and validate the reaction mechanism at relatively high temperatures, while data from a continuously stirred tank reactor (cstr) were used to refine the low temperature portions of the reaction mechanism. In addition to the detailed kinetic modeling, a global or lumped kinetic mechanism was used to study the same experimental results. The lumped model was able to identify key reactions and reaction paths that were most sensitive in each experimental regime and provide important guidance for the detailed modeling effort. In each set of experiments, a region of negative temperature coefficient (NTC) was observed. Variation in pressure from 5 to 40 bars were found to change the temperature range over which the NTC region occurred. Both the lumped and detailed kinetic models reproduced the measured results in each type of experiments, including the features of the NTC region, and the specific elementary reactions and reaction paths responsible for this behavior were identified and rate expressions for these reactions were determined.
Date: April 13, 1995
Creator: Gaffuri, P.; Curran, H.J.; Pitz, W.J. & Westbrook, C.K.
Partner: UNT Libraries Government Documents Department

Dust Combustion Safety Issues for Fusion Applications

Description: This report summarizes the results of a safety research task to identify the safety issues and phenomenology of metallic dust fires and explosions that are postulated for fusion experiments. There are a variety of metal dusts that are created by plasma erosion and disruptions within the plasma chamber, as well as normal industrial dusts generated in the more conventional equipment in the balance of plant. For fusion, in-vessel dusts are generally mixtures of several elements; that is, the constituent elements in alloys and the variety of elements used for in-vessel materials. For example, in-vessel dust could be composed of beryllium from a first wall coating, tungsten from a divertor plate, copper from a plasma heating antenna or diagnostic, and perhaps some iron and chromium from the steel vessel wall or titanium and vanadium from the vessel wall. Each of these elements has its own unique combustion characteristics, and mixtures of elements must be evaluated for the mixture’s combustion properties. Issues of particle size, dust temperature, and presence of other combustible materials (i.e., deuterium and tritium) also affect combustion in air. Combustion in other gases has also been investigated to determine if there are safety concerns with “inert” atmospheres, such as nitrogen. Several coolants have also been reviewed to determine if coolant breach into the plasma chamber would enhance the combustion threat; for example, in-vessel steam from a water coolant breach will react with metal dust. The results of this review are presented here.
Date: May 1, 2003
Creator: Cadwallader, L. C.
Partner: UNT Libraries Government Documents Department

Pulsed Atmospheric Fluidized Bed Combustion. Technical Progress Report, July 1993--September 1993

Description: This quarterly report is broken down between design and the status of the fabrication work being performed. The design section is divided between the following sections: Site layout, foundation design, structural design, piping design, pulse combustor components, and electrical & instrumentation design. As reported in the last quarterly report the location area of the PAFBC in the Clemson Energy Facility was inspected with a view to finalize the layout of the PAFBC plant. Some adjustments were made to the layout to accommodate Clemson University`s requirements and the available space. The most important changes are that the boiler and economizer were relocated in the structure above ground level in order to reduce the size of the footprint of the plant. Figure 1 is the plan view of the current layout. Figures 2 through 6 present different elevation views of the layout. The design of foundations for the entire plant is currently being executed by Industra Engineers Inc. of Greenville, SC. The different weights of various equipment located close to each other precludes the provision of independent foundations for each piece of equipment. One monolithic foundation platform for the whole area proves to be more economical for the current layout. In this quarter the design of the plant structures was completed. The drawings were sent out for expert review and approval. The drawings at this stage present complete structural and platform layout requirements. Changes will be made to various structural members based on the structural review and then detailed drawings of joint design and fabrication cutting plans will be prepared and issued for fabrication.
Date: October 30, 1993
Partner: UNT Libraries Government Documents Department

Pulsed atmospheric fluidized bed combustion. Quarterly technical progress report, April--June 1993

Description: In this quarter the design of the plant structures was completed 70%. The design philosophy of the structure economizes on the use of steel by providing supports for the hot cyclone and hot gas duct connecting the cyclone to the boiler while fulfilling the needs for platforms and walkways at the various levels necessary for operational access. Figures 1 through 6 indicate the layout of the plant structure. At the same time the structure for the Coarse Coal Silo V-2 and Limestone Silo V-4 were incorporated and completed. Following completion of the piping pressure drop calculations, pipe sizing and layout drawings, detailed drawings of the piping in different views are being prepared. The pulse combustor is used to burn fine coal particles and provide an ignition source and supplementary heat to the fluid bed. The following is a description of the components: air plenum, fine coal injectors, aerovalves, water jacket, and tailpipe inserts.
Date: July 30, 1993
Partner: UNT Libraries Government Documents Department

Pulsed atmospheric fluidized bed combustion. Quarterly technical progress report, October 1992--December 1992

Description: The Design and Engineering of most components in the Pulsed Atmospheric Fluidized Bed System was completed prior to September 1992. The components remaining to be designed at that time were: Aerovalves for the Pulse Combustor; Gas and coal injectors for the Pulse Combustor; Lines for PC tailpipes; Air plenum and inlet silencer; Refractory lined hot gas duct connecting outlet hot cyclone to boiler; Structure and platforms, and ladders around PAFBC vessel access and major equipment. Design work is currently in progress on all of the above components. Items 1, 2, 3 and 4 are 50% completed, and items 5 & 6 are 75% complete.
Date: January 1, 1993
Partner: UNT Libraries Government Documents Department

Final Report

Description: The research funded by this grant yielded 20 papers with the P.I as the main author or a co-author. In this report, a brief outline of the completed projects is given.
Date: September 1, 2004
Creator: Cioslowski,J.
Partner: UNT Libraries Government Documents Department

Computational economy improvements in PRISM

Description: The PRISM piecewise solution mapping procedure, in which the solution of the chemical kinetic ODE system is parameterized with quadratic polynomials, is applied to CFD simulations of H{sub 2}+air combustion. Initial cost of polynomial construction is expensive, but it is recouped as the polynomial is reused. We present two methods that help us to parameterize only in places that will ultimately have high reuse. We also implement non-orthogonal Gosset factorial designs, that reduce polynomial construction costs by a factor of two over previously used orthogonal factorial designs.
Date: January 29, 2003
Creator: Tonse, Shaheen R. & Brown, Nancy J.
Partner: UNT Libraries Government Documents Department

Pulsed atmospheric fluidized bed combustion. Technical progress report, January--March 1994

Description: Industra has completed design of the structure which surrounds the fluidized bed. Details regarding their efforts are discussed below. Duke/Fluor Daniel has begun overall design review and will provide comments and recommendations early in the second quarter. Foundation and control room design are complete. Drawings have been submitted to Clemson University and bids have been requested from vendors. Structural design is complete and drawings have been submitted for bids. Industra has reviewed design of the bin structures and has provided recommendations for minor additions to them. Revisions have been made to the structure and are described.
Date: April 29, 1994
Partner: UNT Libraries Government Documents Department

Simulation of lean premixed turbulent combustion

Description: There is considerable technological interest in developingnew fuel-flexible combustion systems that can burn fuels such ashydrogenor syngas. Lean premixed systems have the potential to burn thesetypes of fuels with high efficiency and low NOx emissions due to reducedburnt gas temperatures. Although traditional scientific approaches basedon theory and laboratory experiment have played essential roles indeveloping our current understanding of premixed combustion, they areunable to meet the challenges of designing fuel-flexible lean premixedcombustion devices. Computation, with itsability to deal with complexityand its unlimited access to data, hasthe potential for addressing thesechallenges. Realizing this potential requires the ability to perform highfidelity simulations of turbulent lean premixed flames under realisticconditions. In this paper, we examine the specialized mathematicalstructure of these combustion problems and discuss simulation approachesthat exploit this structure. Using these ideas we can dramatically reducecomputational cost, making it possible to perform high-fidelitysimulations of realistic flames. We illustrate this methodology byconsidering ultra-lean hydrogen flames and discuss how this type ofsimulation is changing the way researchers study combustion.
Date: June 25, 2006
Creator: Bell, John B.; Day, Marcus S.; Almgren, Ann S.; Lijewski, MichaelJ.; Rendleman, Charles A.; Cheng, Robert K. et al.
Partner: UNT Libraries Government Documents Department
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