Author: Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
An experimental study of compressibility effects on the large scale structure and outer variable scaling laws of a coflowing turbulent jet was partially completed. Results showed distinct large scale structure and classical incompressible scaling where the convective Mach number has decreased to subsonic values. At supersonic convective Mach numbers no large scale structure was seen and incompressible scalings were dramatically modified. Experiments also showed strong effects due to oblique shock wave interactions with combustion in supersonic turbulent jets. OH PLIF imaging measurements comparing subsonic and supersonic jets documented striking differences in their mixing and combustion properties. Combined OH/CH PLIF imaging measurements found large differences in the combustion properties of jet flames created by small differences in the fuel injection design. A theoretical study of density effects due to combustion heat release on the outer variable scalings of turbulent shear flows was completed. This study produced a general methodology for predicting the changes in such quantities as growth rates, velocity decay, and entrainment and mixing rates due to heat release. Comparisons with measured heat release effects in the literature, including planar and axisymmetric jet flames as well as mixing layers, showed excellent agreement with this general approach.
Author: Werner Dahm Publisher: ISBN: Category : Languages : en Pages : 9
Book Description
An initial experimental study of the effects of compressibility on the outer variable scalings and large-scale structure of a supersonic coflowing turbulent jet operating in the wake-like mode was completed. The results showed that the large-scale structure is clearly evident in the downstream portion of the flow, where the convective Mach number has become subsonic. However the structures appear to be suppressed in the upstream portion of the flow, at supersonic convective Mach numbers. The results also showed that the local flow width and growth rate in the downstream portions of the flow are good in agreement with the scaling laws for the corresponding incompressible flow.
Author: David M. Mann Publisher: ISBN: Category : Chemical reactions Languages : en Pages : 302
Book Description
Partial contents: Supercritical droplet behavior; Fundamentals of acoustic instabilities in liquid-propellant rockets; Modeling liquid jet atomization proceses; Liquid-propellant droplets dynamics and combustions in supercritical forced convective environments; Contributions of shear coaxial injectors to liquid rocket motor combustion instabilities; High pressure combustion studies under combustion driven oscillatory flow conditions; Droplet collision on liquid propellant combustion; Combustion and plumes; Development of a collisional radiative emission model for strongly nonequilibrium flows; Energy transfer processes in the production of excited states in reacting rocket flows; modeling nonequilibrium radiation in high altitude plumes; kinetics of plume radiation, and of HEDMs and metallic fuels combustion; Nonsteady combustion mechanisms of advanced solid propellants; Chemical mechanisms at the burning surface. p15
Author: Publisher: ISBN: Category : Languages : en Pages : 0
Book Description
Work completed, or in progress, by the end of the first grant year includes a study of the effects of initial conditions on high Reynolds number shear layers, where it was shown that they also influence molecular mixing far downstream of the splitter plate; moderate Reynolds number, liquid-phase transverse jets in a cross flow, including their three-dimensional structure; the discovery of a power-law similarity in the surface-to root-area ratio of scalar structures in liquid-phase turbulent jets; numerical investigations of hydrocarbon ignition and the effects of additives in a high-strain rate environment, as would be encountered in air-breathing scramjet propulsion; and further advances and applications of velocity-field measurements from image sequences of convected scalars.
Author: Mingbo Sun Publisher: Springer ISBN: 9811360251 Category : Technology & Engineering Languages : en Pages : 284
Book Description
Based on research into jets in supersonic crossflow carried out by the authors’ team over the past 15 years, this book summarizes and presents many cutting-edge findings and analyses on this subject. It tackles the complicated mixing process of gas jets and atomization process of liquid jets in supersonic crossflow, and studies their physical mechanisms. Advanced experimental and numerical techniques are applied to further readers’ understanding of atomization, mixing, and combustion of fuel jets in supersonic crossflow, which can promote superior fuel injection design in scramjet engines. The book offers a valuable reference guide for all researchers and engineers working on the design of scramjet engines, and will also benefit graduate students majoring in aeronautical and aerospace engineering.
Author: Paul B. Gooderum Publisher: ISBN: Category : Aeronautics Languages : en Pages : 74
Book Description
The free turbulent mixing of a supersonic jet was investigated with an interferometer, of which a description is given. Density and velocity distributions through the mixing zone were obtained. The velocity distribution was found to be similar to those for imcompressible jets over only the subsonic portion of the mixing pattern.
Author: Ian Thomas Osgerby Publisher: ISBN: Category : Languages : en Pages : 235
Book Description
Chemical kinetic calculations of the combustion time in a constant area scramjet combustion (Mo=7) indicate reaction times 0.00001 secs., and show that the combustion process is usually controlled by diffusion. The mixing process in concentric fueld/air jets is investigated by means of integral forms of the equations of motion and slow mixing requires about 50 diameter. Initial contraction of the slow inner jet is predicted by the theory, and verified by experiment. The simulation of scramjet combustion conditions by a shock tunnel is considered feasible. (Author).
Author: Paul R. Knott Publisher: ISBN: Category : Languages : en Pages : 396
Book Description
This report discusses detailed accounts of major theoretical and experimental investigations directed toward obtaining better understanding and mathematical specification of supersonic turbulent jets. Complete theoretical discussions are given describing the influence of a jet's mean flow shrouding on acoustic radiation of heated and unheated jets, approximate closed form acoustic expressions for turbulent mixing noise characterized by self-noise and shear-noise are given, and theoretical aero-acoustic formulations for the orderly structure of supersonic jets are reviewed. Extensive theory/data comparisons of developed acoustic models are given. Experimental investigations aimed at studying high velocity jet refraction, and the influence of jet swirl and upstream combustion roughness on jet noise is presented. Additionally, an extensive series of laser velocimeter measurements for high velocity and high temperature simple circular jets is discussed. Results include hot-film/laser velocimeter comparisons for ambient jets, mean velocity and turbulent velocity plume surveys of heated supersonic shock-free and shocked flow nozzles, and a demonstration experiment illustrating the capability of performing in-jet turbulence to far-field acoustic cross-correlation. (Author).
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Author: Werner Dahm
Author: David M. Mann
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Author: Mingbo Sun
Author: Ian Thomas Osgerby
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Author: Paul B. Gooderum
Author: Ian Thomas Osgerby
Author: Paul R. Knott