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Author: Meghdad Saediamiri
Publisher:
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Languages : en
Pages : 0
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Biogas is a renewable gaseous fuel with low calorific value and a low burning velocity. This burning characteristic makes stabilizing biogas flame difficult especially in high flow velocity applications, and hence presenting a real challenge for power generation systems. This thesis presents an experimental investigation of the effect of burner geometry (i.e., fuel nozzle geometry and swirl strength of the co-airflow) on the stability limits of a turbulent non-premixed biogas surrogate flame. Three different co-airflow swirl strengths (S = 0, 0.31, 0.79) were implemented using swirl generators with vane angle of 0o, 25o and 50o, respectively. Six different fuel nozzle geometries were used in order to study the effect of fuel jet centerline velocity on the stability limits of a low swirling (i.e., 25o) non-premixed biogas flame. Moreover, the biogas surrogate fuel composition was kept constant (60% CH4 and 40% CO2 by volume) using a mixture of pure methane and carbon dioxide gases. The results of the effect of co-airflow swirl strength on the stability limits of biogas flame revealed that the swirl plays an important role on both the flame mode and its stability limits for both attached and lifted flames. The experimental results revealed that at low swirl strength the attached flame lifts off and stabilizes at a distance above the burner, while at high swirl strength the flame remains attached but shortens and burns blue. Overall, the high swirl attached flame was found to stabilize over a wider range of flow conditions in comparison to the attached and lifted flame produced by low swirl. Importantly, the central fuel jet characteristics (induced by varying the fuel nozzle geometry) were found to drastically influence the upper and lower blowout limits of the low swirl biogas lifted flame, while multi-hole fuel nozzle geometry was found to significantly enhance the stability ranges. 2D PIV data was used to explain the stability limits and the experimental flame results were used to propose semi-empirical correlations capable of describing the turbulent biogas blowout stability limits.
Author: Meghdad Saediamiri
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Biogas is a renewable gaseous fuel with low calorific value and a low burning velocity. This burning characteristic makes stabilizing biogas flame difficult especially in high flow velocity applications, and hence presenting a real challenge for power generation systems. This thesis presents an experimental investigation of the effect of burner geometry (i.e., fuel nozzle geometry and swirl strength of the co-airflow) on the stability limits of a turbulent non-premixed biogas surrogate flame. Three different co-airflow swirl strengths (S = 0, 0.31, 0.79) were implemented using swirl generators with vane angle of 0o, 25o and 50o, respectively. Six different fuel nozzle geometries were used in order to study the effect of fuel jet centerline velocity on the stability limits of a low swirling (i.e., 25o) non-premixed biogas flame. Moreover, the biogas surrogate fuel composition was kept constant (60% CH4 and 40% CO2 by volume) using a mixture of pure methane and carbon dioxide gases. The results of the effect of co-airflow swirl strength on the stability limits of biogas flame revealed that the swirl plays an important role on both the flame mode and its stability limits for both attached and lifted flames. The experimental results revealed that at low swirl strength the attached flame lifts off and stabilizes at a distance above the burner, while at high swirl strength the flame remains attached but shortens and burns blue. Overall, the high swirl attached flame was found to stabilize over a wider range of flow conditions in comparison to the attached and lifted flame produced by low swirl. Importantly, the central fuel jet characteristics (induced by varying the fuel nozzle geometry) were found to drastically influence the upper and lower blowout limits of the low swirl biogas lifted flame, while multi-hole fuel nozzle geometry was found to significantly enhance the stability ranges. 2D PIV data was used to explain the stability limits and the experimental flame results were used to propose semi-empirical correlations capable of describing the turbulent biogas blowout stability limits.
Author: K.J. Syed
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Author: Jaume Lorente Soteras
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Biogas is an alternative renewable energy source that can be used in numerous engineering applications such as power generation systems or transportation as a replacement for fossil fuels. Biogas is a low calorific value gaseous with a low burning velocity that makes it challenging to stabilize biogas flame under certain operating conditions such as high flow velocity applications. The present experimental study aims to investigate the effects of burner geometry (i.e., fuel nozzle geometry and swirling air co-flow) and oxygen enrichment on the stability limits of a turbulent non-premixed biogas flame. Two different fuel nozzle geometries and a swirl generator with vanes angle of 30-degree for the co-airflow were used to study the effect of the central fuel flow inlet conditions and swirl strength of the co-airflow on the stability limits of a non-premixed biogas flame. The biogas surrogate composition was kept constant for all experiments (60% CH4 and 40% CO2). In this study, the air co-flow was oxygen enriched and only biogas surrogate was injected through the central nozzle. The results revealed that the addition of oxygen to the co-airflow has a beneficial impact on the biogas flame stability. The experimental results showed that although oxygen enrichment led to enhanced flame upper stability limit for both single- and seven-hole nozzle, the improvement in the case of the single-hole nozzle is more significant. PIV measurements were performed to explain these improvements in biogas stability limits.
Author:
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Languages : en
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This research documents experiments and analysis of turbulent, lifted, non-premixed diffusion flames in co-flow and with dilution with implications for the development and operation of biogas-fueled combustors. Fuels used in this study were methane and ethylene. The diluent used was nitrogen. General trends were observed in the liftoff and reattachment behavior as affected by dilution of the fuel stream. Initial liftoff velocity was observed to decrease linearly with dilution, while initial lift height behavior was bimodal. Reattachment conditions were similar in overall behavior to liftoff conditions. Co-flow effects were not included in liftoff and reattachment studies. Combined effects of dilution and co-flow were also studied. Stabilization height compared to radial stabilization was found to be bimodal, with behavior differing in the potential core region compared with the far-field region. Dilution was found to decrease the radial stabilization distance, and co-flow tended to increase the radial stabilization distance. However, both effects were minor. The major results involve heat release effects. For given stabilization heights, stabilization velocity was found to decrease with dilution faster than laminar burning velocity with dilution. Stabilization height was also found to increase rapidly with dilution beyond a certain diluent concentration. Flames were also found to taper inward and become more cylindrical in shape as dilution increases. Implications for several flame stabilization theories are discussed. Future work for confirming the results of this research are also discussed.
Author: Shiquan Zhou
Publisher: CRC Press
ISBN: 1315667983
Category : Science
Languages : en
Pages : 2914
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Book Description
Advances in Energy Equipment Science and Engineering contains selected papers from the 2015 International Conference on Energy Equipment Science and Engineering (ICEESE 2015, Guangzhou, China, 30-31 May 2015). The topics covered include:- Advanced design technology- Energy and chemical engineering- Energy and environmental engineering- Energy scien
Author: Irving Fruchtman
Publisher:
ISBN:
Category : Fluid mechanics
Languages : en
Pages : 28
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Author: Boris E. Gelfand
Publisher: Springer Science & Business Media
ISBN: 3642253520
Category : Science
Languages : en
Pages : 338
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Book Description
The potential of hydrogen as an important future energy source has generated fresh interest in the study of hydrogenous gas mixtures. Indeed, both its high caloricity and reactivity are unique properties, the latter underscoring safety considerations when handling such mixtures. The present monograph is devoted to the various aspects of hydrogen combustion and explosion processes. In addition to theoretical and phenomenological considerations, this work also collates the results of many experiments from less well known sources. The text reviews the literature in this respect, thereby providing valuable information about the thermo-gas-dynamical parameters of combustion processes for selected experimental settings in a range of scientific and industrial applications.
Author: Alessandro Parente
Publisher: Frontiers Media SA
ISBN: 2889717003
Category : Technology & Engineering
Languages : en
Pages : 160
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Author:
Publisher:
ISBN:
Category : Power resources
Languages : en
Pages : 840
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Author: Norbert Peters
Publisher: Cambridge University Press
ISBN: 1139428063
Category : Science
Languages : en
Pages : 322
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The combustion of fossil fuels remains a key technology for the foreseeable future. It is therefore important that we understand the mechanisms of combustion and, in particular, the role of turbulence within this process. Combustion always takes place within a turbulent flow field for two reasons: turbulence increases the mixing process and enhances combustion, but at the same time combustion releases heat which generates flow instability through buoyancy, thus enhancing the transition to turbulence. The four chapters of this book present a thorough introduction to the field of turbulent combustion. After an overview of modeling approaches, the three remaining chapters consider the three distinct cases of premixed, non-premixed, and partially premixed combustion, respectively. This book will be of value to researchers and students of engineering and applied mathematics by demonstrating the current theories of turbulent combustion within a unified presentation of the field.
