Download or read book Combustion Stability of a Hydrogen Fuel Jet Issuing Normal to an Airstream written by and published by . This book was released on 1959 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Combustion Stability of a Hydrogen Jet Issuing from a Cylindrical Spray Bar written by Paul D. Reader and published by . This book was released on 1959 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ignition and Combustion of a Transverse Hydrogen Jet in a Mach 2 5 Airstream written by W. J. Thayer and published by . This book was released on 1971* with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Combustion of Hydrogen Injected Into a Supersonic Airstream written by David F. Dyer and published by . This book was released on 1976 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Survey of Hydrogen Combustion Properties written by Isadore L. Drell and published by . This book was released on 1957 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: This literature survey digest of hydrogen-air combustion fundamentals presents data on flame temperature, burning velocity, quenching distance, flammability limits, ignition energy, flame stability, detonation, spontaneous ignition, and explosion limits. The data are assessed, recommended values are given, and relations among various combustion properties are discussed. New material presented includes: theoretical treatment of variation in spontaneous ignition lag with temperature, pressure, and composition, based on reaction kinetics of hydrogen-air composition range for 0.01 to 100 atmospheres and initial temperatures of 0 degrees to 1400 degrees k.
Download or read book Mixing of Hydrogen Injected from Multiple Injectors Normal to a Supersonic Airstream written by R. Clayton Rogers and published by . This book was released on 1971 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hydrogen Aircraft Technology written by G.Daniel Brewer and published by Routledge. This book was released on 2017-11-22 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: Liquid hydrogen is shown to be the ideal fuel for civil transport aircraft, as well as for many types of military aircraft. Hydrogen Aircraft Technology discusses the potential of hydrogen for subsonic, supersonic, and hypersonic applications. Designs with sample configurations of aircraft for all three speed categories are presented, in addition to performance comparisons to equivalent designs for aircraft using conventional kerosine-type fuel and configurations for aircraft using liquid methane fuel. Other topics discussed include conceptual designs of the principal elements of fuel containment systems required for cryogenic fuels, operational elements (e.g., pumps, valves, pressure regulators, heat exchangers, lines and fittings), modifications for turbine engines to maximize the benefit of hydrogen, safety aspects compared to kerosine and methane fueled designs, equipment and facility designs for servicing hydrogen-fueled aircraft, production methods for liquid hydrogen, and the environmental advantages for using liquid hydrogen. The book also presents a plan for conducting the necessary development of technology and introducing hydrogen fuel into the worldwide civil air transport industry. Hydrogen Aircraft Technology will provide fascinating reading for anyone interested in aircraft and hydrogen fuel designs.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1974 with total page 992 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mixing and Combustion of Hydrogen in a Supersonic Airstream written by Malcolm Thomas Jacques and published by . This book was released on 1971 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report is concerned with the mixing and combustion of hydrogen in a high enthalpy Mach 3.5 airstream, in which the conditions are such that the combustion process is mixing limited. The high enthalpy conditions are obtained using a combustion driven hypersonic shock tunnel. A gas composition probe having a response time of 0.25 msec. has been constructed and used in contamination and combustion studies. Combustion results have been obtained from a 2-D Mach 3.5 test section using both a mid-stream vortex generating injector and a plain wedge injector. The turbulent mixing characteristics of the two wakes were determined using a semi-quantitative approach which utilizes well established relationships of structural turbulence theory. The results of this analysis showed the importance of the initial turbulence generation on the overall mixing process. (Author).
Download or read book Mixing and Combustion of Hydrogen in a Supersonic Airstream written by Malcolm Thomas Jacques and published by . This book was released on 1971 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report is concerned with the mixing and combustion of hydrogen in a high enthalpy Mach 3.5 airstream, in which the conditions are such that the combustion process is mixing limited. The high enthalpy conditions are obtained using a combustion driven hypersonic shock tunnel. A gas composition probe having a response time of 0.25 msec. has been constructed and used in contamination and combustion studies. Combustion results have been obtained from a 2-D Mach 3.5 test section using both a mid-stream vortex generating injector and a plain wedge injector. The turbulent mixing characteristics of the two wakes were determined using a semi-quantitative approach which utilizes well established relationships of structural turbulence theory. The results of this analysis showed the importance of the initial turbulence generation on the overall mixing process. (Author).
Download or read book Experimental Investigations of Partially Premixed Hydrogen Combustion in Gas Turbine Environments written by Andrew North and published by . This book was released on 2013 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt: The carbon dioxide emission prevention advantage of generating power with high hydrogen content fuels using gas turbines motivates an improved understanding of the ignition behavior of hydrogen in premixed and partially premixed environments. Hydrogen rich fueled flame stability is sensitive to operating conditions, including environment pressure, temperature, and jet velocity. Furthermore, when premixed or partially premixed operation is desired for nitric oxide emissions reduction, a diluent, such as nitrogen, is often added in allowing fuel/air mixing prior to combustion. Thus, the concentration of the diluent added is an additional independent variable on which flame stability dependence understanding is needed. The focus of this research is on characterizing the dependence of hydrogen jet flame stability on environment temperature, jet velocity, diluent concentration, and pressure by determining the dependence of the liftoff height of lifted flames on these 4 independent parameters. Nitrogen is used as the diluent due to its availability and effectiveness in promoting liftoff. Experiments are first conducted at atmospheric pressure in scoping subsequent research where the additional parameter of pressure is added. The stability and liftoff characteristics of a nitrogen diluted hydrogen jet flame at atmospheric pressure in a vitiated co-flow are investigated experimentally and numerically with particular attention focused on regimes where multiple stabilization mechanisms are active. Information gleaned from this research is instrumental for informing modeling approaches in flame transition situations when both autoignition and flame propagation influence combustion characteristics. Stability regime diagrams which outline the conditions under which the flame is attached, lifted, blown-out, and unsteady are experimentally developed and explored. The stability of the flame is investigated with a 1D Reynolds Averaged Navier Stokes parabolic numerical model which shows that under certain conditions, local turbulent flame speeds exceed the local velocity for the production of stable lifted hydrogen flames. These modeling results suggest that the dominant flame stabilization mechanism is flame propagation, and likely tribrachial flame propagation, consistent with the conclusions of prior studies for jet flames issuing into ambient environments such as the research of Muñiz and Mungal (1997). The lifted regime is further characterized at atmospheric pressure in determining liftoff height dependence on co-flow temperature, jet velocity, and nitrogen dilution. A strong sensitivity of liftoff height to co-flow temperature, jet velocity, and nitrogen dilution is observed. The numerical model results trend well with the experimentally developed stability regime diagrams. Liftoff heights predicted by Kalghatgi's correlation are unable to capture the effects of nitrogen dilution on liftoff height for the heated co-flow cases. A uniquely formulated Damköhler number was therefore developed which acceptably captures the effects of jet velocity, nitrogen dilution and environment temperature on liftoff height. Satisfactory agreement between the correlation results which relies on propagation parameters in its formulation further indicates that stabilization is indeed dominated by propagation. The unsteady regime is also investigated experimentally at atmospheric pressure. The unsteady regime is characterized by rapid ignition events of an initially unburned jet of fuel, and these events are always followed by subsequent blowout events. The frequency by which these ignition events occur are measured and insights are drawn regarding the impact of nitrogen dilution, jet velocity, and co-flow equivalence ratio on ignition frequency. Nitrogen addition to the fuel increases autoignition delay times which reduces ignition frequency, though it also reduces the speed of flame propagation which increases the frequency of blowoff. Consequently, when the level of nitrogen dilution added to the fuel is moderate, increases in dilution increase ignition frequency, and when high levels of nitrogen are added, further increases reduce ignition frequency because each ignition event is preceded by a blowoff event. Jet velocity increases lead to broader ranges of nitrogen dilution where unsteady behavior is observed. Finally, increases in co-flow equivalence ratio result in unsteady behavior for greater levels of nitrogen dilution Experiments are also conducted at elevated pressure with co-flow temperature, jet velocity, and nitrogen dilution still parameterized. Strong sensitivity of liftoff height on co-flow temperature and pressure is observed both when jet velocity and jet Reynolds number are held constant as pressure is varied. With confinement, which is required in achieving elevated pressure, liftoff height sensitivity on jet velocity is diminished. The Damköhler number is again utilized in assessing its utility in incorporating the pressure effect, and satisfactory correlation results are demonstrated. Elevated pressure results and atmospheric pressure results (without confinement) indicate that the Damköhler number can be used in scoping experimental lifted flame research at elevated pressures and temperatures and in informing numerical modeling approaches for research as well as in industry.
Download or read book Stability Regimes of Turbulent Nitrogen Diluted Hydrogen Jet Flames written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: One option for combustion in zero-emission Integrated Gasification Combined Cycle (IGCC) power plants is non-premixed combustion of nitrogen-diluted hydrogen in air. An important aspect to non-premixed combustion is flame stability or anchoring, though only a few fundamental stability studies of these flames have taken place to date. The following paper presents the results of experiments investigating the effects of nitrogen diluent fraction, jet diameter, and exit velocity on the static stability limits of a turbulent hydrogen jet flame issuing from a thin-lipped tube into a quiescent atmosphere. Four different stability limits are observed: detachment from the burner lip, reattachment to the burner lip, transition from a laminar lifted flame base to blowout or to a turbulent lifted flame, and transition from a turbulent lifted flame to blowout. The applicability of existing theories and correlations to the stability results is discussed. These results are an important step in assessing the viability of a non-premixed combustion approach using hydrogen diluted with nitrogen as a fuel.
Download or read book Aerodynamics and Stabilization of Combustion of Hydrogen Jets Injected Into Subsonic Airflow written by J. Koopman and published by . This book was released on 1990 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt: The aerodynamics and stabilization of burning hydrogen jets, injected transversely into a subsonic airstream, have been investigated. The structural behaviour of deflecting cold and burning jets were studied by flow visualization. Experiments and numerical analysis on jet penetration have been performed. Flame extinction limits of wake stabilized flames were established and correlated.
Download or read book Dual Firing of Hydrogen and Heavy Hydrocarbon Fuels written by Michael Lane Seibert and published by . This book was released on 2016 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: Heavy hydrocarbon fuels are common logistics fuel, even for small, mobile systems. In this work, jet fuel is used as a representative heavy hydrocarbon fuel. At low power output (under 2 kilowatts), technologies such as Stirling engines, thermo-electric thermo-photovoltaic generators have the potential to compete with diesel engines, but require reliable jet fuel combustion. Hydrogen enrichment is presented as a control parameter to improve jet fuel combustion. Research in fuel reforming gives an opportunity for hydrogen production at the point of use. Hydrogen enriched combustion of jet fuel seeks to take advantage of the energy density of jet fuel and the combustibility of hydrogen. Experiments were conducted with atomized jet fuel in an open flame. Jet fuel is sprayed through an air atomizing nozzle. Hydrogen was added to either the atomizing air or to a concentric tube supplying the main combustion air. During hydrogen enrichment, jet fuel flow rate was reduced to maintain constant fuel energy input. Temperature is measured vertically and laterally through the flame. Gaseous pollutant emissions were measured above the visible flame. The use of hydrogen and gases other than air to control an air siphon nozzle is demonstrated. In these experiments, hydrogen represented up to 26% of the fuel energy contribution. Substantial changes to the combustion profile occur with small amounts of hydrogen enrichment. Hydrogen enrichment increased peak temperature and reduced standoff distance. It expanded lower flammability limit and reduced emission of unburned hydrocarbons and carbon monoxide. Numerical simulations expanded the results to examine an enclosed burner more suitable for power generation applications. Results showed that at lean conditions, dual firing of hydrogen or reformate with jet fuel provided improved fuel conversion, better flame stability and higher fuel burnout. The advantages provided by dual firing jet fuel and hydrogen represent opportunities for reduced combustor size, improved power system operational reliability and control and reduced pollutant emissions.
Download or read book Technical Abstract Bulletin written by and published by . This book was released on with total page 828 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Unsteady Combustor Physics written by Tim C. Lieuwen and published by Cambridge University Press. This book was released on 2012-08-27 with total page 427 pages. Available in PDF, EPUB and Kindle. Book excerpt: Developing clean, sustainable energy systems is a pre-eminent issue of our time. Most projections indicate that combustion-based energy conversion systems will continue to be the predominant approach for the majority of our energy usage. Unsteady combustor issues present the key challenge associated with the development of clean, high-efficiency combustion systems such as those used for power generation, heating or propulsion applications. This comprehensive study is unique, treating the subject in a systematic manner. Although this book focuses on unsteady combusting flows, it places particular emphasis on the system dynamics that occur at the intersection of the combustion, fluid mechanics and acoustic disciplines. Individuals with a background in fluid mechanics and combustion will find this book to be an incomparable study that synthesises these fields into a coherent understanding of the intrinsically unsteady processes in combustors.
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 1016 pages. Available in PDF, EPUB and Kindle. Book excerpt:
