Download or read book Numerical Study of Cavity Based Flameholder with Slot Injection for Supersonic Combustion written by Independently Published and published by . This book was released on 2016-06-30 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: The current work has focused on finding the optimum cavity properties to enhance themixing phenomenon and combustion processes in supersonic flow using ComputationalFluid Dynamics (CFD) ANSYS Fluent. Various models has been modeled with differentvalues of offset ratios (OR) and aft ramp angles (ϴ) while keeping the length-to-depth ratioconstant. All cavity flows have taken open type i.e. length-to-depth ratio

Download or read book Scramjet Combustion written by Gautam Choubey and published by Butterworth-Heinemann. This book was released on 2022-07-08 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt: Scramjet Combustion explores the development of a high-speed scramjet engine operating in the supersonic/hypersonic range for various air and space transport applications. The book explains the basic structure, components, working cycle, and the relevant governing equations in a clear manner that speaks to both advanced and more novice audiences. Particular attention is paid to efficient air–fuel combustion, looking at both the underlying fundamentals of combustion as well strategies for obtaining optimum combustion efficiency. Methods for reaching the chemically correct air–fuel ratio, subsequent flame, and combustion stabilization as air enters at supersonic speed are also outlined. Further, it includes the continuous on-going efforts, innovations, and advances with respect to the design modification of scramjet combustors, as well as different strategies of fuel injections for obtaining augmented performance while highlighting the current and future challenges. - Outlines the fundamentals of scramjet engines including their basic structure and components, working cycle, governing equations, and combustion fundamentals affecting the combustion and mixing processes - Presents new design modifications of scramjet combustors and different fuel injection strategies including combined fuel injection approaches - Discusses core topics such as chemical kinetics in supersonic flow, fuel–air mixing methods, strategies for combating combustion difficulties, and subsequent flame and combustion stabilization that can be applied to scramjets - Describes the pedagogy for computational approaches in simulating supersonic flows

Download or read book Fuel Air Injection Effects on Combustion in Cavity Based Flameholders in a Supersonic Flow Postprint written by and published by . This book was released on 2005 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effect of direct fuel and air injection was experimentally studied in a cavity-based flameholder in a supersonic flow. Cavity- based fuel injection and flameholding offer an obstruction-free flow path in hydrocarbon-fueled supersonic combustion ramjet (scram jet) engines. Additionally, this study included characterization of the operational limits (i.e., sustained combustion limits) over a variety of fuel and air flow rates. The cavity rearward ramp includes 10 spanwise injection ports at each of 3 axial stations configured to inject air, fuel, and air, respectively. Planar laser-induced fluorescence (PLIF) techniques were utilized to collect planar distributions of the OH radical at various axial locations within the cavity under different flow conditions. A high-speed emissions camera was used to evaluate the combustion across the cavity. Direct injection of both fuel and air provided additional capability to tune the cavity such that a more stable decentralized flame results. The addition of air injection provided the most improvement over the baseline case (fuel only) near the upstream portion of the cavity close to the cavity step.

Download or read book Design and Analysis of Cavity Based Flameholder Using in Supersonic Combustion Flow written by and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental Study of Cavity strut Combustion in Supersonic Flow postprint written by K.-Y. Hsü and published by . This book was released on 2007 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental investigation of cavity-based flameholders with strut injectors in a supersonic flow is reported. In this ongoing research program, emphases are placed on understanding cavity-based flameholders and providing alternative methods for improving overall combustor performance in scramjet engines. Three different struts with fuel injectors are mounted near the cavity leading edge to study flame propagation and ignition of fuel in the core flow region. OH-PLIF (planar laser induced fluorescence) is used to identify the flame zone around the cavity and strut-wake regions over a range of conditions. Shadowgraphy is used to capture the flow features around the strut and cavity. In-stream probing is conducted to characterize the flow features associated with the different strut configurations. Stagnationtemperature profiles are obtained for all struts operating over the same conditions in the combusting-flow study. Two cavity fueling schemes are used to compare flameholder performance. Direct cavity air injection is found to improve combustion significantly. For each strut, upstream and downstream fueling schemes are compared over a range of conditions.--P. i.

Download or read book Fuel air Injection Effects on Combustion in Cavity based Flameholders in a Supersonic Flow written by William H. Allen (Jr.) and published by . This book was released on 2005 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Performance Measurements of Direct Air Injection in a Cavity based Flameholder for a Supersonic Combustor written by Scott G. Edens and published by . This book was released on 2005 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advances in Fluid and Thermal Engineering written by Basant Singh Sikarwar and published by Springer Nature. This book was released on 2021-04-21 with total page 891 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book comprises the select proceedings of the International Conference on Future Learning Aspects of Mechanical Engineering (FLAME 2020). This volume focuses on current research in fluid and thermal engineering and covers topics such as heat transfer enhancement and heat transfer equipment, heat transfer in nuclear applications, microscale and nanoscale transport, multiphase transport and phase change, multi-mode heat transfer, numerical methods in fluid mechanics and heat transfer, refrigeration and air conditioning, thermodynamics, space heat transfer, transport phenomena in porous media, turbulent transport, theoretical and experimental fluid dynamics, flow measurement techniques and instrumentation, computational fluid dynamics, fluid machinery, turbo machinery and fluid power. Given the scope of its contents, this book will be interesting for students, researchers as well as industry professionals.

Download or read book A Computational Fluid Dynamics Analysis of a Cavity Based Flameholder for Scramjet Combustor Applications written by Stephen Alexander Schumaker and published by . This book was released on 2004 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Analysis of Two and Three Dimensional Recessed Flame Holders for Scramjet Applications written by Douglas L. Davis and published by . This book was released on 1996-09-01 with total page 239 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study investigated the flame holding properties of recessed cavities in supersonic flow using numerical analysis techniques. A simplified analytical model indicated that an important property for flame holding was the lower residence time. Several chemical kinetic rate models for hydrogen and hydrocarbon combustion were compared. The perfectly stirred reactor model also indicated that trace species diffusion should increase flame spreading rate, and that heat loss reduces flame holding limits. After nonreacting calibration, two- dimensional simulations confirmed the perfectly stirred reactor results for blowout limits. Also, the effect of trace species diffusion on flame spreading was shown to be negligible, and the reduced flammability with heat loss was confirmed. Lowering the temperature of the inflow boundary layer was shown to reduce the flammability limits. Three-dimensional cavities were shown to generate axial vorticity and slightly enhance flame spreading. The methodology developed in this research provides a design guide for the size of cavity required to provide flame holding for a scramjet combustor. Also, reduction of heat losses was shown to be a method to improve flame holding performance without increasing the cavity size.

Download or read book Supersonic Combustion Experiments with a Cavity Based Fuel Injector Postprint written by and published by . This book was released on 2001 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent results from combustion experiments in a direct-connect supersonic combustor are presented. Successful ignition and sustained combustion of gaseous ethylene have been achieved using an injector/flameholder concept with low-angle, flush-wall fuel injection upstream of a wall cavity. Two interchangeable facility nozzles (Mach 1.8 and 2.2) were used to obtain combustor inlet flow properties that simulate flight conditions between Mach 4 and 6 at a dynamic pressure of 47.9 kPa. Mainstream combustion was achieved at equivalence ratios between 0.25 and 0.75 using only a spark plug and no other external ignition aids. Delta-force levels between 667 and 1779 N were measured, with corresponding combustor pressure ratios between 3.1 and 4.0. Video records of the flame zone show an intensely active combustion zone with rapid flame spreading. One-dimensional performance analysis of the test data indicates a combustion efficiency around 80% with an average combustor skin friction coefficient of 0.0028.

Download or read book Fundamental Studies of Cavity based Flameholder Concepts for Supersonic Combustors written by M. R. Gruber and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fundamental Investigations of an Integrated Fuel Injector Flameholder Concept for Supersonic Combustion written by and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes the results of a recent series of experiments designed to examine the fundamental behavior of several cavity-based flameholder candidates in a non-reacting supersonic flow. Seven geometries were tested in conjunction with a new facility nozzle. Results indicate that the cavity aft ramp plays a strong role in determining the character of the shear layer which spans the length of the cavity. For rectangular cavities, a compression wave forms as the flow separates from the upstream corner of the cavity. Thus, the pressure on the upstream face increases above the freestream value. In these cases, the recompression which occurs at the aft wall is very sharp with strong pressure gradients at the axial location corresponding to the aft wall. These cases are also visibly unsteady. Reductions in the ramp angle yield more stable, two-dimensional flowfields. However, the character of the separation wave changes gradually from compressive to expansive as the ramp angle is reduced. As such, the shear layer tends to dip into the cavity and the recompression occurs more gradually as the shear layer reattaches to the aft wall. Changes in cavity offset ratio result in more dramatic changes in the cavity flowfield. The separation wave becomes strongly expansive leading to severe shear layer intrusion into the cavity. Aft wall changes do not strongly impact the character of the shear layer, although stability is enhanced and recompression is more gradual for shallower ramp angles.

Download or read book Fluid Mechanics and Fluid Power Contemporary Research written by Arun K. Saha and published by Springer. This book was released on 2016-09-20 with total page 1638 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume comprises the proceedings of the 42nd National and 5th International Conference on Fluid Mechanics and Fluid Power held at IIT Kanpur in December, 2014.The conference proceedings encapsulate the best deliberations held during the conference. The diversity of participation in the conference, from academia, industry and research laboratories reflects in the articles appearing in the volume. This contributed volume has articles from authors who have participated in the conference on thematic areas such as Fundamental Issues and Perspectives in Fluid Mechanics; Measurement Techniques and Instrumentation; Computational Fluid Dynamics; Instability, Transition and Turbulence; Turbomachinery; Multiphase Flows; Fluid‐Structure Interaction and Flow‐Induced Noise; Microfluidics; Bio‐inspired Fluid Mechanics; Internal Combustion Engines and Gas Turbines; and Specialized Topics. The contents of this volume will prove useful to researchers from industry and academia alike.

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 291 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 Performance of Pylons Upstream of a Cavity Based Flameholder in Non Reacting Supersonic Flow Postprint written by and published by . This book was released on 2006 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cavity-based fuel injection and flame holding, typically found in hydrocarbon-fueled scramjet applications, are of current interest for use in supersonic combustors. The Air Force Research Lab (AFRL) and the Air Force Institute of Technology (AFlT) are investigating the enhancement of fuel-air mixing with small pylons that project into the supersonic flow upstream of a flame holder. The pylons were of three sizes and were shaped as a thin triangular wedge with a 300 inclination angle. Four configurations (pylons plus baseline) were tested at two different fuel injection pressures in a Mach continuous flow wind tunnel housed at AFRL. The goal was to measure the mixing efficiency and shock loss of each pylon setup for comparison to the baseline condition of transverse injection without pylons. Intrusive and non intrusive techniques were used to obtain pitot pressure, total temperature, cone-static pressure, and laser induced Raman spectroscopy to determine species concentration over the cavity downstream of the injection port. Results showed that pylons increase fuel penetration, while not adding significantly to shock losses or overall mixing.

Download or read book Numerical Study of Innovative Scramjet Inlets Coupled to Combustors Using Hydrocarbon air Mixture written by Faure Joel Malo-Molina and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: To advance the design of hypersonic vehicles, high-fidelity multi-physics CFD is used to characterize 3-D scramjet flow-fields in two novel streamline traced configurations. The two inlets, Jaws and Scoop, are analyzed and compared to a traditional rectangular inlet used as a baseline for on/off-design conditions. The flight trajectory conditions selected are Mach 6 and a dynamic pressure of 1,500 psf (71.82 kPa). Analysis of these hypersonic inlets is performed to investigate distortion effects downstream with multiple single cavity combustors acting as flame holders, and several fuel injection strategies. The best integrated scramjet inlet/combustor design is identified. The flow physics is investigated and the integrated performance impact of the two innovative scramjet inlet designs is quantified. Frozen and finite rate chemistry is simulated with 13 gaseous species and 20 reactions for an Ethylene/air finite-rate chemical model. In addition, URANS and LES modeling are compared to explore overall flow structure and to contrast individual numerical methods. The flow distortion in Jaws and Scoop is similar to some of the distortion in the traditional rectangular inlet, despite design differences. The baseline and Jaws performance attributes are stronger than Scoop, but Jaws accomplishes this while eradicating the cowl lip interaction, and lessening the total drag and spillage penalties.