scholarly journals Experimental Investigation on the Effects of the Geometry of the Pilot Burner on Main Flame

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1115
Author(s):  
Cheol Woo Lee ◽  
In Su Kim ◽  
Jung Goo Hong
Keyword(s):  
Experimental Investigation ◽  
Thermal Damage ◽  
The Novel ◽  
Main Burner ◽  
Wide Range ◽  
Vertical Location ◽  
Burner Flame ◽  
Real Size ◽  
Flame Shape ◽  
Pilot Burner

Various kinds of pilot burners were experimentally investigated to examine the effects of their geometry and their location relative to the main burner of a real size combustor. In addition, a wide range of fuel equivalence ratios were investigated to analyze the feasibility of the novel pilot burner for the conventional burner application. From the results, it is shown that the novel pilot burner with multi air holes had a thin, straight, long and stable pilot flame, while the conventional pilot burner had a thick, lifted, short and unstable flame. It is also shown that the novel pilot burner with an upper air flow hole had a straight pilot flame which led to less thermal damage to the burner combustor. This study suggests that not only pilot burner flame shape but also the vertical location of the pilot burner from the main burner combustor has a significant effect on combustor durability.

scholarly journals Influential parameters of nitrogen oxides emissions for microturbine swirl burner with pilot burner

2010 ◽  
Vol 64 (4) ◽  
pp. 357-363 ◽  
Author(s):  
Miroljub Adzic ◽  
Marija Zivkovic ◽  
Vasko Fotev ◽  
Aleksandar Milivojevic ◽  
Vuk Adzic
Keyword(s):  
Thermal Power ◽  
High Energy ◽  
Nox Emission ◽  
Swirl Number ◽  
Main Burner ◽  
Swirl Flows ◽  
Wide Range ◽  
Micro Turbine ◽  
Influential Parameters ◽  
Pilot Burner

Swirl burners are the most common type of device in wide range of applications, including gas turbine combustors. Due to their characteristics, swirl flows are extensively used in combustion systems because they enable high energy conversion in small volume with good stabilization behavior over the wide operating range. The flow and mixing process generated by the swirl afford excellent flame stability and reduced NOx emissions. Experimental investigation of NOx emission of a purposely designed micro turbine gas burner with pilot burner is presented. Both burners are equipped with swirlers. Mixtures of air and fuel are introduced separately: through the inner swirler - primary mixture for pilot burner, and through the outer swirler - secondary mixture for main burner. The effects of swirl number variations for the both burners were investigated, including parametric variations of the thermal power and air coefficient. It was found that the outer swirler affects the emission of NOx only for the air coefficient less than 1.4. The increase of swirl number resulted in decrease of NOx emission. The inner swirler and thermal power were found to have negligible effect on emission.

Reading Beyond the Code

2018 ◽  
Keyword(s):  
Relevance Theory ◽  
Literary Studies ◽  
The Novel ◽  
Human Communication ◽  
Communicative Acts ◽  
Face To Face ◽  
Code Model ◽  
Wide Range ◽  
Central Claim

This book explores the value for literary studies of relevance theory, an inferential approach to communication in which the expression and recognition of intentions plays a major role. Drawing on a wide range of examples from lyric poetry and the novel, nine of the ten chapters are written by literary specialists and use relevance theory both as an overall framework and as a resource for detailed analysis. The final chapter, written by the co-founder of relevance theory, reviews the issues addressed by the volume and explores their implications for cognitive theories of how communicative acts are interpreted in context. Originally designed to explain how people understand each other in everyday face-to-face exchanges, relevance theory—described in an early review by a literary scholar as ‘the makings of a radically new theory of communication, the first since Aristotle’s’—sheds light on the whole spectrum of human modes of communication, including literature in the broadest sense. Reading Beyond the Code is unique in using relevance theory as a prime resource for literary study, and is also the first to apply the model to a range of phenomena widely seen as supporting an ‘embodied’ conception of cognition and language where sensorimotor processes play a key role. This broadened perspective serves to enhance the value for literary studies of the central claim of relevance theory: that the ‘code model’ is fundamentally inadequate to account for human communication, and in particular for the modes of communication that are proper to literature.

scholarly journals Novel Protein-Repellent and Antibacterial Resins and Cements to Inhibit Lesions and Protect Teeth

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Li Cao ◽  
Junling Wu ◽  
Qiang Zhang ◽  
Bashayer Baras ◽  
Ghalia Bhadila ◽  
...  
Keyword(s):  
Orthodontic Treatment ◽  
The Novel ◽  
Dental Resin ◽  
Biofilm Growth ◽  
New Class ◽  
Dental Resins ◽  
Wide Range ◽  
Oral Biofilms ◽  
One Year

Orthodontic treatment is increasingly popular as people worldwide seek esthetics and better quality of life. In orthodontic treatment, complex appliances and retainers are placed in the patients’ mouths for at least one year, which often lead to biofilm plaque accumulation. This in turn increases the caries-inducing bacteria, decreases the pH of the retained plaque on an enamel surface, and causes white spot lesions (WSLs) in enamel. This article reviews the cutting-edge research on a new class of bioactive and therapeutic dental resins, cements, and adhesives that can inhibit biofilms and protect tooth structures. The novel approaches include the use of protein-repellent and anticaries polymeric dental cements containing 2-methacryloyloxyethyl phosphorylcholine (MPC) and dimethylaminododecyl methacrylate (DMAHDM); multifunctional resins that can inhibit enamel demineralization; protein-repellent and self-etching adhesives to greatly reduce oral biofilm growth; and novel polymethyl methacrylate resins to suppress oral biofilms and acid production. These new materials could reduce biofilm attachment, raise local biofilm pH, and facilitate the remineralization to protect the teeth. This novel class of dental resin with dual benefits of antibacterial and protein-repellent capabilities has the potential for a wide range of dental and biomedical applications to inhibit bacterial infection and protect the tissues.

Experimental Investigation of Subsonic Turbulent Flow Over Single and Double Backward Facing Steps

1962 ◽  
Vol 84 (3) ◽  
pp. 317-325 ◽  
Author(s):  
D. E. Abbott ◽  
S. J. Kline
Keyword(s):  
Experimental Investigation ◽  
Velocity Profile ◽  
Flow Pattern ◽  
Reynolds Numbers ◽  
Area Ratio ◽  
Single Step ◽  
Reattachment Length ◽  
Double Step ◽  
Wide Range ◽  
Geometric Variables

Results are presented for flow patterns over backward facing steps covering a wide range of geometric variables. Velocity profile measurements are given for both single and double steps. The stall region is shown to consist of a complex pattern involving three distinct regions. The double step contains an assymmetry for large expansions, but approaches the single-step configuration with symmetric stall regions for small values of area ratio. No effect on flow pattern or reattachment length is found for a wide range of Reynolds numbers and turbulence intensities, provided the flow is fully turbulent before the step.

Experimental investigation of isothermal and reacting flow characteristics downstream of axisymmetric bluff body stabilizers under stratified or fully premixed inlet mixture conditions

2020 ◽  
Author(s):  
Γεώργιος Πατεράκης
Keyword(s):  
Experimental Investigation ◽  
Turbulent Flow ◽  
Bluff Body ◽  
Operating Conditions ◽  
Reacting Flow ◽  
Wide Range ◽  
Flow Features ◽  
Air Mixing ◽  
The Impact ◽  
Stratified Flames

The current work describes an experimental investigation of isothermal and turbulent reacting flow field characteristics downstream of axisymmetric bluff body stabilizers under a variety of inlet mixture conditions. Fully premixed and stratified flames established downstream of this double cavity premixer/burner configuration were measured and assessed under lean and ultra-lean operating conditions. The aim of this thesis was to further comprehend the impact of stratifying the inlet fuelair mixture on the reacting wake characteristics for a range of practical stabilizers under a variety of inlet fuel-air settings. In the first part of this thesis, the isothermal mean and turbulent flow features downstream of a variety of axisymmetric baffles was initially examined. The effect of different shapes, (cone or disk), blockage ratios, (0.23 and 0.48), and rim thicknesses of these baffles was assessed. The variations of the recirculation zones, back flow velocity magnitude, annular jet ejection angles, wake development, entrainment efficiency, as well as several turbulent flow features were obtained, evaluated and appraised. Next, a comparative examination of the counterpart turbulent cold fuel-air mixing performance and characteristics of stratified against fully-premixed operation was performed for a wide range of baffle geometries and inlet mixture conditions. Scalar mixing and entrainment properties were investigated at the exit plane, at the bluff body annular shear layer, at the reattachment region and along the developing wake were investigated. These isothermal studies provided the necessary background information for clarifying the combustion properties and interpreting the trends in the counterpart turbulent reacting fields. Subsequently, for selected bluff bodies, flame structures and behavior for operation with a variety of reacting conditions were demonstrated. The effect of inlet fuel-air mixture settings, fuel type and bluff body geometry on wake development, flame shape, anchoring and structure, temperatures and combustion efficiencies, over lean and close to blow-off conditions, was presented and analyzed. For the obtained measurements infrared radiation, particle image velocimetry, laser doppler velocimetry, chemiluminescence imaging set-ups, together with Fouriertransform infrared spectroscopy, thermocouples and global emission analyzer instrumentation was employed. This helped to delineate a number of factors that affectcold flow fuel-air mixing, flame anchoring topologies, wake structure development and overall burner performance. The presented data will also significantly assist the validation of computational methodologies for combusting flows and the development of turbulence-chemistry interaction models.

Stranger Fictions

2021 ◽  
Author(s):  
Rebecca C. Johnson
Keyword(s):  
World Literature ◽  
Arab World ◽  
Central Place ◽  
Arabic Literature ◽  
The Novel ◽  
Reading Practices ◽  
Global Circulation ◽  
Wide Range ◽  
History Of ◽  
Modern Arabic

Zaynab, first published in 1913, is widely cited as the first Arabic novel, yet the previous eight decades saw hundreds of novels translated into Arabic from English and French. This vast literary corpus influenced generations of Arab writers but has, until now, been considered a curious footnote in the genre's history. Incorporating these works into the history of the Arabic novel, this book offers a transformative new account of modern Arabic literature, world literature, and the novel. This book rewrites the history of the global circulation of the novel by moving Arabic literature from the margins of comparative literature to its center. Considering the wide range of nineteenth- and early-twentieth-century translation practices, the book argues that Arabic translators did far more than copy European works; they authored new versions of them, producing sophisticated theorizations of the genre. These translations and the reading practices they precipitated form the conceptual and practical foundations of Arab literary modernity, necessitating an overhaul of our notions of translation, cultural exchange, and the global. The book shows how translators theorized the Arab world not as Europe's periphery but as an alternative center in a globalized network. It affirms the central place of (mis)translation in both the history of the novel in Arabic and the novel as a transnational form itself.

scholarly journals Synthesis of photoreactive solvent-free acrylic pressure-sensitive adhesives in the recovered system

2007 ◽  
Vol 9 (2) ◽  
pp. 5-9 ◽  
Author(s):  
Roland Milker ◽  
Zbigniew Czech ◽  
Marta Wesołowska
Keyword(s):  
Organic Solvent ◽  
Solvent Free ◽  
The Novel ◽  
Pressure Sensitive Adhesive ◽  
Adhesive Film ◽  
Pressure Sensitive Adhesives ◽  
Pressure Sensitive ◽  
Wide Range ◽  
Protective Films ◽  
New Type

Synthesis of photoreactive solvent-free acrylic pressure-sensitive adhesives in the recovered system The present paper discloses a novel photoreactive solvent-free acrylic pressure-sensitive adhesive (PSA) systems, especially suitable for the so much adhesive film applications as the double-sided, single-sided or carrier-free technical tapes, self-adhesive labels, protective films, marking and sign films and wide range of medical products. The novel photoreactive solvent-free pressure-sensitive adhesives contain no volatile organic compounds (residue monomers or organic solvent) and comply with the environment and legislation. The synthesis of this new type of acrylic PSA is conducted in common practice by solvent polymerisation. After the organic solvent are removed, there remains a non-volatile, solvent-free highly viscous material, which can be processed on a hot-melt coating machine at the temperatures of about 100 to 140°C.

Method for Non-Dimensional Tip Leakage Flow Characterization in Radial Turbines

2018 ◽  
Author(s):  
José Ramón Serrano ◽  
Roberto Navarro ◽  
Luis Miguel García-Cuevas ◽  
Lukas Benjamin Inhestern
Keyword(s):  
Suction Side ◽  
Tip Clearance ◽  
Navier Stokes ◽  
The Novel ◽  
Tip Leakage Flow ◽  
Navier Stokes Equation ◽  
Tip Clearance Flow ◽  
Tip Leakage ◽  
Wide Range ◽  
Clearance Flow

Tip leakage loss characterization and modeling plays an important role in small size radial turbine research. The momentum of the flow passing through the tip gap is highly related with the tip leakage losses. The ratio of fluid momentum driven by the pressure gradient between suction side and pressure side and the fluid momentum caused by the shroud friction has been widely used to analyze and to compare different sized tip clearances. However, the commonly used number for building this momentum ratio lacks some variables, as the blade tip geometry data and the viscosity of the used fluid. To allow the comparison between different sized turbocharger turbine tip gaps, work has been put into finding a consistent characterization of radial tip clearance flow. Therefore, a non-dimensional number has been derived from the Navier Stokes Equation. This number can be calculated like the original ratio over the chord length. Using the results of wide range CFD data, the novel tip leakage number has been compared with the traditional and widely used ratio. Furthermore, the novel tip leakage number can be separated into three different non-dimensional factors. First, a factor dependent on the radial dimensions of the tip gap has been found. Second, a factor defined by the viscosity, the blade loading, and the tip width has been identified. Finally, a factor that defines the coupling between both flow phenomena. These factors can further be used to filter the tip gap flow, obtained by CFD, with the influence of friction driven and pressure driven momentum flow.

scholarly journals Buckling behavior of cold-formed steel columns at both ambient temperature and simulated fire conditions

Fire Research ◽  
2016 ◽  
Author(s):  
Hélder D. Craveiro ◽  
João Paulo C. Rodrigues ◽  
Luís M. Laím
Keyword(s):  
Experimental Investigation ◽  
Ambient Temperature ◽  
Cross Sections ◽  
Failure Modes ◽  
Steel Columns ◽  
Buckling Behavior ◽  
Wide Range ◽  
Cold Formed Steel ◽  
Simulated Fire ◽  
Fire Conditions

Cold-formed steel (CFS) profiles with a wide range of cross-section shapes are commonly used in building construction industry. Nowadays several cross-sections can be built using the available standard single sections (C, U, Σ, etc.), namely open built-up and closed built-up cross-sections. This paper reports an extensive experimental investigation on the behavior of single and built-up cold-formed steel columns at both ambient and simulated fire conditions considering the effect of restraint to thermal elongation. The buckling behavior, ultimate loads and failure modes, of different types of CFS columns at both ambient and simulated fire conditions with restraint to thermal elongation, are presented and compared. Regarding the buckling tests at ambient temperature it was observed that the use of built-up cross-sections ensures significantly higher values of buckling loads. Especially for the built-up cross-sections the failure modes were characterized by the interaction of individual buckling modes, namely flexural about the minor axis, distortional and local buckling. Regarding the fire tests, it is clear that the same levels of restraint used in the experimental investigation induce different rates in the generated restraining forces due to thermal elongation of the columns. Another conclusion that can be drawn from the results is that by increasing the level of restraint to thermal elongation the failure of the columns is controlled by the generated restraining forces, whereas for lower levels of restraint the temperature plays a more important role. Hence, higher levels of imposed restraint to thermal elongation will lead to higher values of generated restraining forces and eventually to lower values of critical temperature and time.

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