Download or read book Combustion of the Fuel air Mixture in the Vicinity of a Cantilevered Ramp Fuel Injector in a Hypervelocity Flow written by Viorel Turcu and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The flow field in the immediate vicinity of a cantilevered ramp fuel injector is investigated in order to determine whether premature ingition occurs while the fuel/air mixing process is taking place. Two configurations of cantilevered ramp injectors are studied: the "A" configuration injector (with non-zero compression and expansion angles), and the "B" configuration injector (with zero compression angle and non-zero expansion angle). The study was conducted using a laminar, three-dimensional, multispecies flowsolver developed in generalized coordinates to solve the Navier-Stokes equations with hydrogen/air finite rate chemistry. The method consists of an upwind TVD scheme for the discretization of the convective fluxes coupled with a semi-implicit LU-SGS scheme for temporal discretization. The finite-rate chemistry model chosen for the present study includes 9 species (H2, O2, H, O, OH, H2O, HO2, and N2) and 20 reactions. The chemical solver assumes that the nitrogen is inert, which is a valid assumption when the static temperatures do not exceed 3000 K. The analysis of the numerical solutions shows that premature ignition occurs for both configurations considered in the present study. The fuel is ignited by the hot air which is raising from the boundary layers corresponding to the lower wall of the channel that contains the fuel injectors.

Download or read book Combustion of the Fuel air Mixture in the Vicinity of a Cantilevered Ramp Fuel Injector in a Hypervelocity Flow written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Simulation of Cantilevered Ramp Injector Flow Fields for Hypervelocity Fuel air Mixing Enhancement written by Jurgen Schumacher and published by . This book was released on 2000 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Increasing demand for affordable access to space and high speed terrestrial transport has spawned research interest into various air-breathing hypersonic propulsion systems. Propulsion concepts such as the supersonic combustion ramjet (scramjet) and the shock-induced combustion ramjet (shcramjet) utilize oxygen freely available in the atmosphere and thereby substantially reduce the weight penalty of on-board oxidizer tankage used in rocket based systems. Of key importance to the ultimate success of an air-breathing concept is the ability to efficiently mix the fuel with atmospheric air. In the case of a hypersonic air-breather the challenge is accentuated due to the requirement of supersonic combustion. Flow velocities through the combustor on the order of thousands of meters per second provide the fuel and air with only a brief time to adequately combine. Contemporary mixing augmentation methods to address this issue have focused on fuel injection devices which promote axial vortices to enhance the mixing process. Much research effort has been expended on investigation of ramp injectors for this purpose. The present study introduces a new ramp injector design, based on the conventional ramp injector, dubbed the cantilevered ramp injector. A two-pronged numerical approach was employed to investigate the mixing performance and characteristics of the cantilevered injector consisting of, (1) comparison with conventional designs and (2) a parametric study of various cantilevered injector geometries. A laminar, three-dimensional, multispecies flowsolver was developed in generalized coordinates to solve the Navier-Stokes equations for the flow fields of injected H2 into high-enthalpy air. The scheme consists of an upwind TVD scheme for discretization of the convective fluxes coupled with a semi-implicit LU-SGS scheme for temporal discretization. Through analysis of the numerical solutions, it has been shown that the cantilevered ramp injector is a viable fuel injection system facilitating enhanced mixing of fuel and air. Comparison with conventional designs have revealed a competitive and, in most cases, superior design in the context of mixing performance. A strong counter-rotating vortex pair generated under the cantilevered injector was shown to be the distinguishing characteristic of this design and largely accounted for improved mixing performance. Results also elucidated the importance of a coupled design approach between the fuel injector and propulsive duct to optimize mixing performance.

Download or read book Numerical Simulation of Cantilevered Ramp Injector Flow Fields for Hypervelocity Fuel air Mixing Enhancement written by and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Progress Report on Research Supported by Grants from the Defense Research Board of Canada written by University of Toronto. Institute for Aerospace Studies and published by . This book was released on 2000 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Simulation of Cantilevered Ramp Injector Flow Fields for Hypervelocity Fuel written by Jurgen Schumacher and published by National Library of Canada = Bibliothèque nationale du Canada. This book was released on 2000 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book AIAA Journal written by American Institute of Aeronautics and Astronautics and published by . This book was released on 2006 with total page 1380 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Altitude Performance of an Afterburner with Pentaborane Fuel written by James W. Useller and published by . This book was released on 1957 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 1042 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental Behavior of Combustion Products of HEF 2 and Air During Expansion in Exhaust Nozzles written by J. Robert Branstetter and published by . This book was released on 1960 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Hypersonic Mixed compression Inlet Shock induced Combustion Ramjets written by Derrick Alexander and published by . This book was released on 2006 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study investigates the performance and flow field features of a mixed-compression inlet shock-induced combustion ramjet (shcramjet). In a shcramjet, oncoming air is compressed with shocks in the inlet and then further compressed and mixed with hydrogen fuel in a duct prior to shock-induced combustion and expansion of the combustion products through a divergent nozzle to provide thrust. Numerical studies are undertaken using the WARP code that solves the Favre-averaged Navier-Stokes equations closed by the Wilcox k-o turbulence model. Hydrogen/air combustion is solved via the twenty reaction, nine species combustion model of Jachimowski. Mixing augmentation through the use of cantilevered ramp injector arrays on opposite shcramjet inlet walls is studied and the influence of relative array locations is quantified. Increased spanwise distance between adjacent injectors on opposite walls allows for increased jet penetration and fuel distributions in the center of the engine duct. Chemically reacting studies verify an air buffer is created between the fuel and walls that suppresses premature ignition while still allowing for an air based mixing efficiency of up to 0.46-0.54. Combustion is produced over aerodynamic wedges with the spatial flow variation dictating both detonation and shock-induced combustion can be present over constant angle wedges. The initial inlet angle must be as high as possible, while avoiding premature ignition, to generate the pressure in the combustor needed for significant positive thrust. Thrust production from combustion is found to be insensitive to wedge angle if combustion is initiated across the cross-sectional area. Strong recirculation regions are formed via shock/boundary layer interactions in the confined engine duct. Mitigation of the recirculation is demonstrated with correct placement of the nozzle expansion in conjunction with air blowing in the boundary layer at a mass flow rate on the order of that of the fuel injection. For flight at Mach 11 the mixed-compression inlet shcramjet is found to generate a specific impulse of 683 s in the simulation of a realistic three-dimensional flow field.

Download or read book Stability Limits and Efficiency of Swirl can Combustor Modules Burning Natural Gas Fuel written by Nicholas R. Marchionna and published by . This book was released on 1970 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Afterburner Performance of Circular V gutters and a Sector of Parallel V gutters for a Range of Inlet Temperatures to 1255 K 1800 F written by J. Robert Branstetter and published by . This book was released on 1973 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: Combustion tests of two V-gutter types were conducted in a 19.25-in. diameter duct using vitiated air. Fuel spraybars were mounted in line with the V-gutters. Combustor length was set by flame-quench water sprays which were part of a calorimeter for measuring combustion efficiency. Although the levels of performance of the parallel and circular array afterburners were different, the trends with geometry variations were consistent. Therefore, parallel arrays can be used for evaluating V-gutter geometry effects on combustion performance. For both arrays, the highest inlet temperature produced combustion efficiencies near 100 percent. A 5-in. spraybar - to - V-gutter spacing gave higher efficiency and better lean blowout performance than a spacing twice as large. Gutter durability was good.

Download or read book Study of Streamwise Vorticity stirred Combustion written by and published by . This book was released on 1993 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 The Ignition of Various Fuel air Mixtures in High Velocity Flow by Heated Rods written by Moreland Russell Irby and published by . This book was released on 1948 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

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.