Download or read book Structure and Dynamics of Fuel Jets Injected Into a High Temperature Subsonic Crossflow written by and published by . This book was released on 2015 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: An investigation of subsonic transverse jet injection into a subsonic vitiated crossflow is discussed. The reacting jet in crossflow (RJIC) system investigated as a means of secondary injection of fuel in a staged combustion system. The measurements were performed in test rigs featuring (a) a steady, swirling crossflow and (b) a crossflow with low swirl but significant oscillation in the pressure field and in the axial velocity. The rigs are referred to as the steady state rig and the instability rig. Rapid mixing and chemical reaction in the near field of the jet injection is desirable in this application. Temporally resolved velocity measurements within the wake of the reactive jets using 2D-PIV and OH-PLIF at a repetition rate of 5 kHz were performed on the RJIC flow field in a steady state water-cooled test rig. The reactive jets were injected through an extended nozzle into the crossflow which is located in the downstream of a low swirl burner (LSB) that produced the swirled, vitiated crossflow. Both H2/N2 and natural gas (NG)/air jets were investigated. OH-PLIF measurements along the jet trajectory show that the auto-ignition starts on the leeward side within the wake region of the jet flame. The measurements show that jet flame is stabilized in the wake of the jet and wake vortices play a significant role in this process. PIV and OH-PLIF measurements were performed at five measurement planes along the cross- section of the jet. The time resolved measurements provided significant information on the evolution of complex flow structures and highly transient features like, local extinction, re-ignition, vortex-flame interaction prevalent in a turbulent reacting flow. Nanosecond-laser-based, single-laser-shot coherent anti-Stokes Raman scattering (CARS) measurements of temperature and H2 concentraiton were also performed. The structure and dynamics of a reacting transverse jet injected into a vitiated oscillatory crossflow presents a unique opportunity for applying advanced experimental diagnostic techniques with increasing fidelity for the purposes of computational validation and model development. Numerical simulation of the reacting jet in crossflow is challenging because of the complex vortical structures in the flowfield and compounded by an unsteady crossflow. The resulting benchmark quality data set will include comprehensive, accurate measurements of mean and fluctuating components of velocity, pressure, and flame front location at high pressure and with crossflow conditions more representative of modern gas turbine engines. A proven means for producing combustion dynamics is used for the performing combustion instability experimental study on a reacting jet in crossflow configuration. The method used to provide an unsteady flowfield into which the transverse jet is injected is a unique and novel approach that permits elevated temperature and pressure conditions. A model dump combustor is used to generate and sustain an acoustically oscillating vitiated flow that serves as the crossflow for transverse jet injection studies. A fully optically accessible combustor test section affords full access surrounding the point of jet injection. High speed 10 kHz planar measurements OH PLIF and high frequency 180 kHz wall pressure measurements are performed on the injected reacting transverse jet and surrounding flowfield, respectively, under simulated unstable conditions. The overlay of the jet velocity flowfield and the flame front will be investigated using simultaneous 10 kHz OH PLIF and PIV in experiments to be performed in the near future.
Download or read book Numerical Investigations of a High Frequency Pulsed Gaseous Fuel Jet Injection Into a Supersonic Crossflow written by Nehemiah Joel Williams and published by . This book was released on 2016 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: The investigation of fuel delivery mechanisms is a critical design point in the development of supersonic combustion ramjet (scramjet) technology. Primary challenges include proper penetration of the jet in the supersonic crossflow while keeping total pressure losses and wall drag to a minimum. To reduce drag and heat loads especially at high burner entry Mach numbers it is desirable to use a minimally intrusive means of fuel delivery. Pulsation of gaseous jets has been shown to increase penetration and mixing in subsonic flows. A limited number of experimental studies and even fewer numerical studies have suggested that when applied to supersonic crossflows, gaseous jets pulsed in the kilohertz range of frequencies improve jet penetration and mixing. To improve on the limited number of numerical studies of pulsed jets in supersonic crossflows (PJISF), 2D and 3D computational fluid dynamics (CFD) simulation models of non-excited (steady) and sinusoidally excited (pulsed) jets were constructed using ANSYS FLUENT 15.0. The 2D investigation included pulsation at 8,16, 32 and 48 kHz. These simulation results showed that pulsation at 16 kHz provided the best jet penetration improvement in the jet near field and far field among all frequencies sampled. A 3D wall-modeled Large Eddy Simulation (WMLES) was constructed with the goals resolving large scale turbulent flow structure and observing the time evolution of a jet pulsed in a supersonic crossflow, as well as to compare the effects of sinusoidal pulsation at 16 kHz with steady injection for the same flow conditions as the 2D case. A comparison of the jet trajectories between the steady and pulsed injection cases demonstrated that for sinusoidal pulsation of a jet at 16 kHz over the equivalent cycle averaged injection total pressure and momentum flux ratio, jet penetration is improved over the steady jet, up to 50% in the near field of the jet. Furthermore, improved mass concentration decay associated with jet-crossflow mixing and far field total pressure recovery has been demonstrated as a result of pulsation of the jet.
Download or read book Jet in Supersonic Crossflow written by Mingbo Sun and published by Springer. This book was released on 2019-02-18 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Scramjets written by Mostafa Barzegar Gerdroodbary and published by Butterworth-Heinemann. This book was released on 2020-07-21 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: Scramjet engines are a type of jet engine and rely on the combustion of fuel and an oxidizer to produce thrust. While scramjets are conceptually simple, actual implementation is limited by extreme technical challenges. Hypersonic flight within the atmosphere generates immense drag, and temperatures found on the aircraft and within the engine can be much greater than that of the surrounding air. Maintaining combustion in the supersonic flow presents additional challenges, as the fuel must be injected, mixed, ignited, and burned within milliseconds. Fuel mixing, along with the configuration and positioning of the injectors and the boundary conditions, play a key role in combustion efficiency. Scramjets: Fuel Mixing and Injection Systems discusses how fuel mixing efficiency and the advantage of injection systems can enhance the performance of the scramjets. The book begins with the introduction of the supersonic combustion chamber and explains the main parameters on the mixing rate. The configuration of scramjets is then introduced with special emphasis on the main effective parameters on the mixing of fuel inside the scramjets. In addition, basic concepts and principles on the mixing rate and fuel distribution within scramjets are presented. Main effective parameters such as range of fuel concentration for the efficient combustion, pressure of fuel jet and various arrangement of jet injections are also explained. This book is for aeronautical and mechanical engineers as well as those working in supersonic combustion who need to know the effects of compressibility on combustion, of shocks on mixing and on chemical reactions, and vorticity on the flame anchoring. Explains the main applicable approaches for enhancement of supersonic combustion engines and the new techniques of fuel injection Shows how the interaction of main air stream with fuel injections can develop the mixing inside the scramjets Presents results of numerical simulations and how they can be used for the development of the combustion engines
Download or read book Jet in Supersonic Crossflow written by Mingbo Sun and published by . This book was released on 2019 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Surface Measurements of a Supersonic Jet in Subsonic Compressible Crossflow for the Validation of Computational Models written by and published by . This book was released on 2002 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: Despite many decades of jet-in-crossflow experimentation, a distinct lack of data remains for a supersonic jet exhausting into a subsonic compressible crossflow. The present investigation seeks to address this deficiency by examining the flowfield structure of a Mach 3.73 jet injected transversely from a flat plate into a subsonic compressible freestream. The experimental results described herein include the mean surface pressure field as mapped using static pressure taps on the flat plate and an identification of flow features by employing an oil-based surface flow tracer. The possibility of flow separation within the nozzle itself also is addressed using pressure taps along the nozzle interior wall, as is the asymmetry of the separation line due to the variation of the local backpressure around the perimeter of the nozzle orifice resulting from the jet-in-crossflow interaction. Pressure data both on the flat plate and within the nozzle are presented at numerous angles with respect to the crossflow freestream direction to provide a breadth of measurements throughout the interaction region. Since the data are intended for use in validating computational models, attention is paid to providing details regarding the experimental geometry, boundary conditions, flowfield nonuniformities, and uncertainty analyses. Eight different sets of data are provided, covering a range of values of the jet-to-freestream dynamic pressure ratio from 2.8 to 16.9 and a freestream Mach number range of 0.5 to 0.8.
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1978 with total page 540 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Energy Research Abstracts written by and published by . This book was released on 1993-02 with total page 366 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Current Hydraulic Laboratory Research in the United States written by and published by . This book was released on 1970 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 702 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NBS Special Publication written by and published by . This book was released on 1968 with total page 540 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hydraulic Research in the United States 1970 written by United States. National Bureau of Standards and published by . This book was released on 1971 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hydraulic Research in the United States written by and published by . This book was released on 1969 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hydraulic Research in the United States and Canada written by United States. National Bureau of Standards and published by . This book was released on 1968 with total page 1046 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Experimental Simulation of Liquid Fuel Injection Into a Heated Subsonic Gas Crossflow written by Patrick William Hewitt and published by . This book was released on 1982 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA Technical Memorandum written by and published by . This book was released on 1994 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Engineering Index Annual written by and published by . This book was released on 1992 with total page 2264 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since its creation in 1884, Engineering Index has covered virtually every major engineering innovation from around the world. It serves as the historical record of virtually every major engineering innovation of the 20th century. Recent content is a vital resource for current awareness, new production information, technological forecasting and competitive intelligence. The world?s most comprehensive interdisciplinary engineering database, Engineering Index contains over 10.7 million records. Each year, over 500,000 new abstracts are added from over 5,000 scholarly journals, trade magazines, and conference proceedings. Coverage spans over 175 engineering disciplines from over 80 countries. Updated weekly.
