Numerical Investigation on Hydrogen/air Non-premixed Combustion in a Three-dimensional Micro Combustor PDF Download

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Languages : en
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Author: Huahua Xiao
Publisher: Springer
ISBN: 3662483793
Category : Technology & Engineering
Languages : en
Pages : 162

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This thesis offers important new insights into and a deeper understanding of premixed flame instabilities and hydrogen safety. Further, it explains the underlying mechanisms that control the combustion processes in tubes. The author’s previous scientific accomplishments, which include a series of high-quality publications in the best journals in our field, Combustion and Flame and International Journal of Heat and Mass Transfer, are very impressive and have already made a significant contribution to combustion science.

Author: Udo Gerke
Publisher: Cuvillier Verlag
ISBN: 3867274991
Category : Hydrogen as fuel
Languages : en
Pages : 39

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Author: Md Nazmuzzaman Khan
Publisher:
ISBN:
Category : Combustion engineering
Languages : en
Pages : 292

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Ignition by a jet of hot combustion product gas injected into a premixed combustible mixture from a separate pre-chamber is a complex phenomenon with jet penetration, vortex generation, flame and shock propagation and interaction. It has been considered a useful approach for lean, low-NOx combustion for automotive engines, pulsed detonation engines and wave rotor combustors. The hot-jet ignition constant-volume combustor (CVC) rig established at the Combustion and Propulsion Research Laboratory (CPRL) of the Purdue School of Engineering and Technology at Indiana University-Purdue University Indianapolis (IUPUI) is considered for numerical study. The CVC chamber contains stoichiometric methane-hydrogen blends, with pre-chamber being operated with slightly rich blends. Five operating and design parameters were investigated with respect to their effects on ignition timing. Di fderent pre-chamber pressure (2, 4 and 6 bar), CVC chamber fuel blends (Fuel-A: 30% methane + 70% hydrogen and Fuel-B: 50% methane + 50% hydrogen by volume), active radicals in pre-chamber combusted products (H, OH, O and NO), CVC chamber temperature (298 K and 514 K) and pre-chamber traverse speed (0.983 m/s, 4.917 m/s and 13.112 m/s) are considered which span a range of fluid-dynamic mixing and chemical time scales. Ignition delay of the fuel-air mixture in the CVC chamber is investigated using a detailed mechanism with 21 species and 84 elementary reactions (DRM19). To speed up the kinetic process adaptive mesh refinement (AMR) based on velocity and temperature and multi-zone reaction technique is used. With 3D numerical simulations, the present work explains the effects of pre-chamber pressure, CVC chamber initial temperature and jet traverse speed on ignition for a speci fic set of fuels. An innovative post processing technique is developed to predict and understand the characteristics of ignition in 3D space and time. With the increase of pre-chamber pressure, ignition delay decreases for Fuel-A which is the relatively more reactive fuel blend. For Fuel-B which is relatively less reactive fuel blend, ignition occurs only for 2 bar pre-chamber pressure for centered stationary jet. Inclusion of active radicals in pre-chamber combusted product decreases the ignition delay when compared with only the stable species in pre-chamber combusted product. The effects of shock-flame interaction on heat release rate is observed by studying flame surface area and vorticity changes. In general, shock-flame interaction increases heat release rate by increasing mixing (increase the amount of deposited vorticity on flame surface) and flame stretching. The heat release rate is found to be maximum just after fast-slow interaction. For Fuel-A, increasing jet traverse speed decreases the ignition delay for relatively higher pre-chamber pressures (6 and 4 bar). Only 6 bar pre-chamber pressure is considered for Fuel-B with three di fferent pre-chamber traverse speeds. Fuel-B fails to ignite within the simulation time for all the traverse speeds. Higher initial CVC temperature (514 K) decreases the ignition delay for both fuels when compared with relatively lower initial CVC temperature (300 K). For initial temperature of 514 K, the ignition of Fuel-B is successful for all the pre-chamber pressures with lowest ignition delay observed for the intermediate 4 bar pre-chamber pressure. Fuel-A has the lowest ignition delay for 6 bar pre-chamber pressure. A specific range of pre-chamber combusted products mass fraction, CVC chamber fuel mass fraction and temperature are found at ignition point for Fuel-A which were liable for ignition initiation. The behavior of less reactive Fuel-B appears to me more complex at room temperature initial condition. No simple conclusions could be made about the range of pre-chamber and CVC chamber mass fractions at ignition point.

Author: Sandro Nižetić
Publisher: Springer
ISBN: 3319898450
Category : Technology & Engineering
Languages : en
Pages : 889

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This book is devoted to the analysis and applications of energy, exergy, and environmental issues in all sectors of the economy, including industrial processes, transportation, buildings, and services. Energy sources and technologies considered are hydrocarbons, wind and solar energy, fuel cells, as well as thermal and electrical storage. This book provides theoretical insights, along with state-of-the-art case studies and examples and will appeal to the academic community, but also to energy and environmental professionals and decision makers.

Author: Miguel Alejandro Gutiérrez Contreras
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Non-premixed combustion process is an important subject in most applications of combustion. Understanding of this phenomenon is crucial in the design of reliable, efficient, economical power generation systems. Microfabrication technologies in the development of power micro electro-mechanical systems is also becoming an increasing trend nowadays and the complete understanding of microfluid dynamics and non-premixed micro-combustion phenomena will lead the success in this field. In recent years numerical simulations have become an essential tool to understand combustion process to overcome experimental problems without losing accuracy. In this study, two numerical simulations were performed on the analysis of the effect of injection on the turbulent mixing quality in a simple combustor and on the dynamics non-premixed flame street in a mesoscale channel using the commercial software Fluent®. The effect of inlet geometries were first investigated for a Lockwood-type combustor in terms of combustion and energy efficiency and an efficient design configuration is deduced. The effect of wall temperature and flow velocities on the dynamics of non-premixed flame in a scaled combustion channel was investigated in the second part of this study. The results suggest that the two main parameters affecting the development of a non-premixed flame street in a mesoscale channel are the heat transfer to and from the wall and the diffusion time of the flow. The analysis of numerical details such as grid resolution, turbulent and chemistry models is emphasized throughout the study to understand the influence of these numerical parameters on the simulated phenomenon by comparing with experimental observations.

Author: Ashwani K. Gupta
Publisher: Springer Nature
ISBN: 9811559961
Category : Technology & Engineering
Languages : en
Pages : 939

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Book Description
This book comprises select peer-reviewed proceedings of the 26th National Conference on IC Engines and Combustion (NCICEC) 2019 which was organised by the Department of Mechanical Engineering, National Institute of Technology Kurukshetra under the aegis of The Combustion Institute-Indian Section (CIIS). The book covers latest research and developments in the areas of combustion and propulsion, exhaust emissions, gas turbines, hybrid vehicles, IC engines, and alternative fuels. The contents include theoretical and numerical tools applied to a wide range of combustion problems, and also discusses their applications. This book can be a good reference for engineers, educators and researchers working in the area of IC engines and combustion.

Author: Anil Kumar
Publisher: Springer Nature
ISBN: 9811596786
Category : Science
Languages : en
Pages : 1134

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This book presents the select proceedings of the second International Conference on Recent Advances in Mechanical Engineering (RAME 2020). The topics covered include aerodynamics and fluid mechanics, automation, automotive engineering, composites, ceramics and polymers processing, computational mechanics, failure and fracture mechanics, friction, tribology and surface engineering, heating and ventilation, air conditioning system, industrial engineering, IC engines, turbomachinery and alternative fuels, machinability and formability of materials, mechanisms and machines, metrology and computer-aided inspection, micro- and nano-mechanics, modelling, simulation and optimization, product design and development, rapid manufacturing technologies and prototyping, solid mechanics and structural mechanics, thermodynamics and heat transfer, traditional and non-traditional machining processes, vibration and acoustics. The book also discusses various energy-efficient renewable and non-renewable resources and technologies, strategies and technologies for sustainable development and energy & environmental interaction. The book is a valuable reference for beginners, researchers, and professionals interested in sustainable construction and allied fields.

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Category :
Languages : en
Pages :

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Author: Fernando F. Grinstein
Publisher: Cambridge University Press
ISBN: 1316571742
Category : Technology & Engineering
Languages : en
Pages : 481

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Small-scale turbulent flow dynamics is traditionally viewed as universal and as enslaved to that of larger scales. In coarse grained simulation (CGS), large energy-containing structures are resolved, smaller structures are spatially filtered out, and unresolved subgrid scale (SGS) effects are modeled. Coarse Grained Simulation and Turbulent Mixing reviews our understanding of CGS. Beginning with an introduction to the fundamental theory the discussion then moves to the crucial challenges of predictability. Next, it addresses verification and validation, the primary means of assessing accuracy and reliability of numerical simulation. The final part reports on the progress made in addressing difficult non-equilibrium applications of timely current interest involving variable density turbulent mixing. The book will be of fundamental interest to graduate students, research scientists, and professionals involved in the design and analysis of complex turbulent flows.