Download or read book Effect of Swirl Cup on Characteristics of Fuel Spray in Gas Turbine Combustors written by Jong-Hoon Park 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 Flashback and Blowoff Characteristics of Gas Turbine Swirl Combustor written by Mohammed Abdulsada and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Gas turbines are extensively used in combined cycle power systems. These form about 20% of global power generating capacity, normally being fired on natural gas, but this is expected in the future to move towards hydrogen enriched gaseous fuels to reduce CO2 emissions. Gas turbine combined cycles can give electrical power generation efficiencies of up to 60%, with the aim of increasing this to 70% in the next 10 to 15 years, whilst at the same time substantially reducing emissions of contaminants such as NOx. The gas turbine combustor is an essential and critical component here. These are universally stabilized with swirl flows, which give very wide blowoff limits, and with appropriate modification can be adjusted to give very low NOx and other emission. Lean premixed combustion is commonly used at pressures between 15 to 30 bar, these even out hot spots and minimise formation of thermal NOx. Problems arise because improving materials technology/improved cooling techniques allow higher turbine inlet temperatures, hence higher efficiencies, but with the drawback of potentially higher emissions and stability problems. This PhD study has widely investigated and analysed two different kinds of gas turbine swirl burners. The research has included experimental investigation and computational simulation. Mainly, the flashback and blowoff limits have been comprehensively analysed to investigate their effect upon swirl burner operation. The study was extended by using different gas mixtures, including either pure gas or a combination of more than one gas like natural gas, methane, hydrogen and carbon dioxide. The first combustor is a 100 kW tangential swirl combustor made of stainless steel that has been experimentally and theoretically analysed to study and mitigate the effect of flashback phenomena. The use of a central fuel injector, cylindrical confinement and exhaust sleeve are shown to give large benefits in terms of flashback resistance and acts to reduce and sometimes eliminate any coherent structures which may be located along the axis of symmetry. The Critical Boundary Velocity Gradient is used for characterisation of flashback, both via the original Lewis and von Elbe formula and via new analysis using CFD and investigation of boundary layer conditions just in front of the flame front. Conclusions are drawn as to mitigation technologies. It is recognized how isothermal conditions produce strong Precessing Vortex Cores that are fundamental in producing the ii final flow field, whilst the Central Recirculation Zones are dependent on pressure decay ratio inside the combustion chamber. Combustion conditions showed the high similarity between experiments and simulation. Flashback was demonstrated to be a factor highly related to the strength of the Central Recirculation Zone for those cases where a Combustion Induced Vortex Breakdown was allowed to enter the swirl chamber, whilst cases where a bluff body impeded its passage showed a considerable improvement to the resistance of the phenomenon. The use of nozzle constrictions also reduced flashback at high Reynolds number (Re). All these results were intended to contribute to better designs of future combustors. The second piece of work of this PhD research included comprehensive experimental work using a generic swirl burner (with three different blade inserts to give different swirl numbers) and has been used to examine the phenomena of flashback and blowoff in the swirl burner in the context of lean premixed combustion. Cylindrical and conical confinements have been set up and assembled with the original design of the generic swirl combustor. In addition to that, multi-fuel blends used during the experimental work include pure methane, pure hydrogen, hydrogen / methane mixture, carbon dioxide/ methane mixture and coke oven gas. The above investigational analysis has proved the flashback limits decrease when swirl numbers decrease for the fuel blends that contain 30% or less hydrogen. Confinements would improve the flashback limit as well. Blowoff limits improve with a lower swirl number and it is easier to recognise the gradual extinction of the flame under blowoff conditions. The use of exhaust confinement has created a considerable improvement in blowoff. Hydrogen enriched fuels can improve the blowoff limit in terms of increasing heat release, which is higher than heat release with natural gas. However, the confinements complicate the flashback, especially when the fuel contains a high percentage of hydrogen. The flashback propensity of the hydrogen/methane blends becomes quite strong. The most important features in gas turbines is the possibility of using different kinds of fuel. This matter has been discussed extensively in this project. By matching flashback/blowoff limits, it has been found that for fuels containing up to 30% of hydrogen, the designer would be able to switch the same gas turbine combustor to multifuels whilst producing the same power output.
Download or read book Fuel Effects on Operability of Aircraft Gas Turbine Combustors written by Meredith Colket and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In summarizing the results obtained in the first five years of the National Jet Fuel Combustion Program (NJFCP), this book demonstrates that there is still much to be learned about the combustion of alternative jet fuels.
Download or read book Coarse Grained Simulation and Turbulent Mixing written by Fenando F. Grinstein and published by Cambridge University Press. This book was released on 2016-06-30 with total page 481 pages. Available in PDF, EPUB and Kindle. Book excerpt: Reviews our current understanding of the subject. For graduate students and researchers in computational fluid dynamics and turbulence.
Download or read book Emissions Control in Swirl Stabilized Spray Combusters an Experimental and Computational Study written by and published by . This book was released on 2007 with total page 49 pages. Available in PDF, EPUB and Kindle. Book excerpt: Detailed measurements of velocity statistics, temperature distribution, flame chemiluminescence, and emission characteristics in a lean direct fuel injection multi swirl gas turbine combustor were acquired. The inlet and exit boundary conditions, including the mixing tube length and the exhaust nozzle contraction ratio, were modified to emphasize the effects of these boundary conditions on the characteristics of nonreacting and reacting flows. Velocity statistics, including mean and turbulence kinetics, were measured by using SPIV in a cylindrical combustor chamber for isothermal and reacting flow cases. The velocity spectra at different locations were measured using hot-wire anemometry. The temperature distribution along the combustor radial direction was measured using thermocouples at different axial locations for a variety of multi-swirl configurations. The exhaust emissions of NOx and CO were measured as a function of fuel/air ratio. The data along with the detailed description of the experimental setup and operating conditions can be used to validate modeling approaches to swirling flows, the turbulence/chemistry interaction.
Download or read book Investigations of the Effects of Spray Characteristics on the Flame Pattern and Combustion Stability of a Swirl cup Combustor written by and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fuel Effects on Gas Turbine Combustors and Engines An Annotated Bibliography written by COORDINATING RESEARCH COUNCIL INC ATLANTA GA. and published by . This book was released on 1981 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: Partial Contents Include: (1) Flame Radiation, Combustion Liner Temperature, and Combustor Liner Durability; (2) Exhaust Smoke and Soot Formation; (3) Gaseous Emissions and Combustion Efficiency; (4) Flame Ignition and Stability, Reaction Rates, and Spray Characteristics; and (5) Carbon Deposition.
Download or read book Gas Turbine Combustor Design Problems written by Arthur Henry Lefebvre and published by Hemisphere Pub. This book was released on 1980 with total page 458 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Swirl on Fuel Variability in Gas Turbine Combustors written by Praveen P. Reddy and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 36th AIAA ASME SAE ASEE Joint Propulsion Conference Exhibit 2000 3350 2000 3399 written by and published by . This book was released on 2000 with total page 578 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Performance and emission characteristics of swirl can combustors to a near stoichiometric fuel air ratio written by Larry A. Diehl and published by . This book was released on 1976 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of Fuel Properties and Atomization on Ignition in a T63 Turbine Combustor written by David W. Naegeli and published by . This book was released on 1987 with total page 79 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experiments were performed in a T63 gas turbine combustor to gain a better understanding of the roles played by fuel properties, atomization, and air velocity and temperature in cold start ignition. These results were used to improve the characteristic time model for ignition in gas turbine combustors. Ignition tests were performed on ten fuels while varying reference velocity, burner inlet temperature, fuel/air ratio, and the Sauter Mean Diameter of the fuel spray. Fuel viscosity and volatility were varied over a wide range. The test fuels ranged from gasoline to a heavy marine gas oil (HMGO). Two fuel groups were blended with identical viscosities, but the strikingly different 10 percent boil-off temperatures. to examine the effect of fuel composition on ignition, two fuels were blended with unusually high aromatic contents. Droplet size and spray structure were varied by using six atomizers. Atomization, Fuel effects, Alternative fuels, Ignition, Fuel sprays. (mjm).
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 Flow Field Measurements in a Counter swirl Stabilized Liquid Combustor written by Jonathan A. Colby and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: To adhere to the current requirements for NOx and CO emissions in combustion systems, modern land and air based gas turbine engines often operate in the fuel lean regime. While operating near the lean blow out (LBO) limit does reduce some harmful emissions, combustor stability is sacrificed and extinction becomes a major concern. To fully understand the characteristics of lean operation, an experimental study was conducted to map the time averaged flow field in a typical industrial, counter-swirling, liquid fuel combustor. This study examined two steady-state operating conditions, both near the lean extinction limit for this swirl burner. Using an LDV/PDPA system, 2-D mean and fluctuating velocities, as well as Reynolds stresses, were measured throughout the combustor. These measurements were taken for both the non-reacting and reacting flow fields, enabling a direct analysis of the result of heat addition and increased load on a turbulent swirling flow field. To further understand the overall flow field, liquid droplet diameter measurements were taken to determine the fuel spray characteristics as a function of operating pressure and rated spray angle. Chemical composition at the combustor exit was also measured, with an emphasis on the concentrations of both CO and NOx emissions. This large database of aerodynamic and droplet measurements improves understanding of the swirling, reacting flow field and aids in the accurate prediction of lean blow-out events. With this understanding of the lean blow-out limit, increased fuel efficiency and decreased pollutant emissions can be achieved in industrial combustors, especially those used for thrust in the airline industry.
Download or read book GAS Turbine Combustion Second Edition written by Arthur H. Lefebvre and published by CRC Press. This book was released on 1998-09-01 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt: This revised edition provides understanding of the basic physical, chemical, and aerodynamic processes associated with gas turbine combustion and their relevance and application to combustor performance and design. It also introduces the many new concepts for ultra-low emissions combustors, and new advances in fuel preparation and liner wall-cooling techniques for their success. It details advanced and practical approaches to combustor design for the clean burning of alternative liquid fuels derived from oil shades, tar sands, and coal. Additional topics include diffusers, combustion performance fuel injection, combustion noise, heat transfer, and emissions.
Download or read book Investigation on the Internal Flow Characteristics of Pressure swirl Atomizers written by Zhanhua Ma and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The performance of liquid fuel atomizer in gas turbine combustor has direct effects on flame stability, combustion efficiency, and pollutant emissions. Therefore, further understanding of the underlying physics of these atomizers is one of the primary requirements for advanced gas turbine combustor design. Simplex atomizers are commonly used in air-breathing gas turbine engines because they produce good atomization characteristics and are relatively simple and inexpensive to manufacture. Internal flow characteristics of simplex nozzles play a very important role on the atomizer performance. So it is of great practical interest to examine the relationships between internal flow characteristics, nozzle design variables, and important spray features. Part I of this dissertation revealed the detailed flow structure inside simplex atomizers through the DPIV and LDV study. The internal flow field is generally symmetric except very near the inlet slot plane. The velocity profiles are very similar at different axial locations within the swirl chamber. The discharge parameters were measured and used to examine the correlations from previous researchers. Detailed flow field information was linked with the discharge parameters to obtain more insight into the nozzle performance. The relationship between the internal flow characteristics and discharge parameters confirmed that the internal flow structure plays a very important role on the atomizer performance. Part II presents the internal flow structure of large-scale simplex nozzles at two different working-fluid/ambient-fluid density ratios. The effects of density ratio, Reynolds number and orifice geometry on the internal flow field were examined by using a 2-D LDV probe. At the higher density ratio, Reynolds number and orifice geometry has little impact on the internal flow field. At the lower density ratio, the orifice contraction angle has little effect on the internal flow field, whereas the expansion angle can significantly affect the internal flow structure. A dominant frequency was found from the velocity frequency analysis, which indicates that the internal flow is controlled by certain dominant frequency. A dimensionless dominant frequency, similar to the Strouhal number in the flow past a cylinder, was defined using the orifice diameter and mean axial velocity in the orifice. In the part III of this dissertation, the internal flow field of the simplex atomizer with macrolaminated geometry was measured by using the refractive index matching fluid method and DPIV system. In the swirl chamber, the liquid flow is unsteady and exhibits 3-D features, which is more evident as the flow rate increases. In the orifice, the liquid flow is more uniform and axisymmetrical. The discharge parameters were measured and compared with the correlations from previous researchers.
Download or read book Fuel Spray Characteristics of Gas Turbine Fuel Injectors at Cold Start Conditions written by Theodore R. Koblish and published by . This book was released on 1995 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presented at the International Gas Turbine and Aeroengine Congress and Exposition, Houston, Texas - June 5-8, 1995.
