BEGIN:VCALENDAR VERSION:2.0 PRODID:-//wp-events-plugin.com//6.6.4.4//EN TZID:Asia/Jerusalem X-WR-TIMEZONE:Asia/Jerusalem BEGIN:VEVENT UID:0-524@aerospace.technion.ac.il DTSTART;TZID=Asia/Jerusalem:20150527T163000 DTEND;TZID=Asia/Jerusalem:20150527T173000 DTSTAMP:20230603T193205Z URL:https://aerospace.technion.ac.il/events/investigation-of-h2o-vitiated- combustion-in-a-low-equivalence-turbo-jet-combustor/ SUMMARY:Investigation of H2O-Vitiated Combustion in a Low-Equivalence Turbo -Jet Combustor DESCRIPTION:Lecturer:Akiva M.G. Sharma\n Faculty:Department of Aerospace En gineering\n Institute:Technion – Israel Institute of Technology\n Locati on:Classroom 165\, ground floor\, Library\, Aerospace Eng.\n Zoom: \n Abst ract: \n Details: \n Today\, more than ever before\, the necessity of prod ucing low emissions gas turbines is of paramount importance. Reducing the emission of Nitrogen Oxides in particular has been of primary focus. In th is vein\, there has been a continuing trend towards a higher degree of fue l-air premixing prior to combustion for the sake of reducing NOx emission. The various methods that have been developed for this purpose are not wit hout their flaws however. Some may decrease NOx while increasing CO and UH C emissions. Some may decrease NOx while sacrificing thermal efficiency. A s such there is still a search for a technology that can combine the stren gths of all the methods without any of their weaknesses.  Flameless oxida tion is a technology that has been developed during the last two decades a nd shows promise for being an alternative method of achieving low NOx emis sions. Thus far\, it has been successfully applied to industrial furnaces. The patented combustion principle of flameless oxidation (FLOX®)\, devel oped by WS Wärmeprozesstechnik is based on high internal flue gas recircu lation which leads to a dilution of the combustion zone. The high recircul ation ratios are achieved by the momentum of the air and fuel jets enterin g the combustion chamber.\nThe work contained herein is twofold\; in the f irst part atmospheric experiments are conducted on a cylindrical\, lean\, non-premixed combustor. Various combustor design parameters such as fuel-a ir injection configuration\, oxidizer pre-heating\, and steam injection ar e investigated with respect to flame temperature\, volume and emission for mation. Based on this work\, a novel combustor design is developed\, which is capable of burning methane as a stand-alone combustor\, or part of a s equential system that contains water as an inlet constituent.\nIn the seco nd part of the work\, the combustion chamber is modeled as a chemical reac tor network in order to select a reduced chemical mechanism for numerical calculations. The physical chamber was meshed and CFD simulations were per formed under matching boundary conditions to that which experimental measu rements were taken using the selected reduced mechanism.  CFD results for a basic case are validated using the experimental results and show excell ent agreement with the NOx\, and temperature measurements. The CFD is used to gain further insight into the effect of water injection on methane com bustion. It is shown that steam effectively reduces the NOx production by dilution of the flame as well as by a chemical route wherein the concentra tion of the OH radical pool changes and affects the chemistry of the NOx f ormation.  It has been demonstrated that while pre-heating does indeed en hance mixing inside the chamber and thus promotes flameless combustion\, i t also increases NOx production and at sufficient levels of H2O dilution\, preheating is unnecessary.  A combination of preheating and H2O vitiate allows for predictions of ultra-low pollutant levels and smooth temperatur e profiles at lower recirculation values prescribed by other authors. A no vel combustor design and injector configuration has been designed that pre dicts characteristic emissions and properties of flameless combustion. CATEGORIES:Seminars LOCATION:Classroom 165\, ground floor\, Library\, Aerospace Eng. END:VEVENT BEGIN:VTIMEZONE TZID:Asia/Jerusalem X-LIC-LOCATION:Asia/Jerusalem BEGIN:DAYLIGHT DTSTART:20150327T030000 TZOFFSETFROM:+0200 TZOFFSETTO:+0300 TZNAME:IDT END:DAYLIGHT END:VTIMEZONE END:VCALENDAR