Download or read book Study of Effects of Injector Geometry on Fuel air Mixing and Combustion written by Louis Hilmer Bangert and published by . This book was released on 1977 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Influence of Injector Geometry on Fuel air Mixing and Combustion Performance of a Model Combustor written by Leonel Arellano-Ochoa and published by . This book was released on 2000 with total page 308 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 Computational and Experimental Study of Geometry Modifications Inside a Flow blurring Injector written by Nathan James Vardaman and published by . This book was released on 2018 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt: Liquid fuel atomization is widely used for combustion in many applications. With the strong emphasis on emissions regulations coupled with the ever increasing drive to improve energy efficiency, all aspects of combustion are being thoroughly researched. One key way to achieve the above goals is further improvement in the liquid fuel atomization process. Better atomization improves mixing of fuel and air, thus results in lower emissions, whereas improved liquid fuel injector designs can improve energy efficiency. The flow-blurring (FB) atomization technique, developed recently and investigated at the University of Alabama, has shown promise in both these areas. Previous research has shown that the FB injector produces smaller droplets and a more desirable droplet distribution than the commercial air-blast injector. In addition, the FB injector is able to successfully atomize a wider range of fuels, and it is much less susceptible to the change in surface tension or viscosity of the liquid fuel. In this study, a computational fluid dynamics (CFD) model is created to mimic the mixing of the fuel and air inside the injector, and thus, understand the underlying physics of the FB atomization process. The 2D model is assumed to be asymmetric and incompressible, and it uses the mixture model for the two-phase flow. A transient solution is found and analyzed revealing a recirculation zone, due to a stagnation point near the exit, is formed within the fuel tube of the injector. The recirculation zone is responsible for the mixing of fuel and air and the formation of bubbles. Prior experimental research conclusions are compared with the model as various operating conditions are implored for verification of the models accuracy. Finally, the model is utilized by simulating and studying the effect of geometric modifications within the wall gap of the FB injector. An inner-slant wall gap provides promising results compared to the original geometry. The geometry modifications are then implemented in an actual injector tested in an atmospheric burner. Emissions measurements, thermal imaging of the combustor surface, and OH* chemiluminescence imaging of the flame are used to first verify proper operation of the combustor and then to characterize the flame structure. Several operating conditions are altered and the influence of these changes is studied. OH* chemiluminescence images reveal the flame is stable and a better distribution of OH* signals represents improved atomization. Finally, the geometric modifications to the injector are tested to determine the performance improvements with respect to the baseline design. Experimental results of the different geometries indicate the injector with inner-slant seems to improve the atomization process. The inner-slant injector has lower emissions for a range of ALR values and a lower pressure drop though the injector compared to the original geometry.
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 The Effect of Fuel Injector Geometry on the Flow Structure of a Swirl Stabilized Gas Turbine Burner microform written by Anning, Grant H. G. (Grant Hugh Gary) and published by Ann Arbor, Mich. : University Microfilms International. This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents an experimental study on the effect of geometry on the flow structure of experimental swirl-stabilized gas turbine burners. The purpose of this project was to test a number of geometric changes to a burner and determine how these changes affected the flow field in order to evaluate how they might affect a combustion process. Tests were initially conducted in a water channel on several full-scale experimental burner models, which included the use of elliptic outlet geometries and a vortex breakdown stabilizer. Velocity and phase-averaged PLIF measurements are presented for the different burner configurations. More extensive measurements were then conducted in a cold flow air channel on a series of one-quarter scale experimental swirlers. The scale models were designed with different geometries in order to test the effect of different blade angles and spacings. The models were also tested with a vortex breakdown stabilizer and a mixing section located between the swirler outlet and the sudden expansion. A scale model burner with an elliptic outlet was also tested. Stereo PIV measurements are presented for the different configurations. Water channel measurements identified axial oscillation of the vortex breakdown bubble as the primary driving mechanism behind combustion instabilities. Tests showed that the elliptic geometry damped oscillation of the breakdown bubble and the vortex breakdown stabilizer physically anchored the breakdown bubble inside the burner cone. Tests in the air channel showed that wider blade spacing resulted in a reduced swirl number and a weaker vortex breakdown. A wider blade angle was observed to increase the swirl and the strength of the vortex breakdown. Certain configurations of the breakdown stabilizer were seen to increase the strength of the vortex breakdown while other configurations forced it to form in an unstable configuration. The use of a mixing section at the swirler outlet caused the vortex breakdown bubble to propagate upstream inside of the mixing tube. The elliptic swirler exhibited a very complex flow structure, indicative of axis-switching.
Download or read book NASA s University Program written by United States. National Aeronautics and Space Administration. Office of University Affairs and published by . This book was released on with total page 696 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modeling the Effects of Engine Speed and Fuel Injection Strategies on Power Density and Emission Levels written by Michael F. Stoia and published by . This book was released on 1998 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of the Fuel Air Mixing on Combustion Instabilities and NOx Emissions in Lean Premixed Combustion written by Wessam Estefanos and published by . This book was released on 2016 with total page 205 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental study was conducted to investigate the effects of the fuel-air mixing on combustion instabilities and NO x emissions in lean premixed combustion. High speed PIV measurements in water were conducted to capture the mean and dynamic behavior of the cold flow generated by a 3X model of the tested premixer. High speed PLIF in water measurements were conducted to quantify the mean and unsteady fuel-air mixing at different momentum flux ratios. Atmospheric combustion tests using the original premixer, were conducted using natural gas and propane at the same momentum flux ratios of the PLIF mixing tests. An emissions analyzer was used to measure the emissions from combustion tests. Dynamic pressure transducers were used to measure the amplitude and the frequency of the dynamic pressure oscillations associated with the combustion instabilities. CHEMKIN-PRO was used to model the atmospheric combustion and predict NO x emissions at different conditions. Results showed that unsteady fuel-air mixing was concentrated at the center and near the outer edges of the premixer. These regions were characterized by high fuel concentration gradients. With the increase in the momentum flux ratio, the concentration gradient and the level of unsteady mixing increased, indicating that the fuel-air spatial unmixedness was the source of the unsteady mixing. It was found that local flow turbulence tended to decrease the concentration gradient through enhancing the fuel-air mixing, which resulted in decreasing the level of unsteady mixing. NO x emissions from atmospheric combustion increased with the increase in the momentum flux ratio due to the increase in the flame temperature and the fuel-air spatial and temporal unmixedness. The intensity of the combustion dynamics increased with the increase in the level of unsteady mixing. Axial injection of the fuel into the regions of strong unsteady mixing eliminated the combustion dynamics through damping the unsteady mixing. Results of CHEMKIN-PRO agreed very well with the experimental results and showed that the spatial and temporal unmixedness have a significant effect on NO x emissions for very lean combustion (F = 0.4). With the increase in the equivalence ratio, their relative contribution decreased.
Download or read book Effects of Intake Flow on Mixing and Combustion in Direct Injection Diesel Engines Using Multidimensional Modeling written by Philip William Stephenson and published by . This book was released on 1995 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Gas Turbine Combustion written by Arthur H. Lefebvre and published by CRC Press. This book was released on 2010-04-26 with total page 560 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reflecting the developments in gas turbine combustion technology that have occurred in the last decade, Gas Turbine Combustion: Alternative Fuels and Emissions, Third Edition provides an up-to-date design manual and research reference on the design, manufacture, and operation of gas turbine combustors in applications ranging from aeronautical to po
Download or read book The Scramjet Engine written by Corin Segal and published by Cambridge University Press. This book was released on 2009-06-22 with total page 271 pages. Available in PDF, EPUB and Kindle. Book excerpt: Demand for high-speed propulsion has renewed development of the supersonic combustion ramjet engine (Scramjet engine) for hypersonic flight applications.
Download or read book NASA s University Program Active Grants and Research Contracts written by and published by . This book was released on 1976 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Visual Study of Influence of Combustion Chamber Configurations on Fuel air Mixing Process in D I Diesel Engine Using Liquid liquid Injection Technique written by Takashi Watanabe and published by . This book was released on 1990 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fuel air Mixing and Combustion in Swirl Direct Injection Diesel Engines written by A. Y. O. Barrishi and published by . This book was released on 1990 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Scramjet Fuel Injector Design Parameters and Considerations Development of a Two dimensional Tangential Fuel Injector with Constant Pressure at the Flame written by and published by . This book was released on 1972 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt:
