An Influence of a Fluidic Oscillator Insertion in a Swirl-Stabilized Burner on Turbulent Premixed Flame

2018 ◽  
Vol 141 (6) ◽  
Author(s):  
Sameh H. Hassan ◽  
Ahmed A. Emara ◽  
Mahmoud A. Elkady
Keyword(s):  
Flame Structure ◽  
Digital Camera ◽  
Operating Conditions ◽  
Experimental Program ◽  
Temperature Profiles ◽  
Liquefied Petroleum Gas ◽  
Reference Case ◽  
Turbulent Premixed Flame ◽  
The Impact ◽  
Ev Burner

A series of experiments were performed on a vertical EV burner with a constant coflow air of 873 L/min to generate turbulent lean premixed flow in order to study the impact of the addition of acetylene/argon mixture to the liquefied petroleum gas (LPG) on the temperature field and flame structure. The fluidics mechanism was inserted at a fixed position inside the entry section of the EV burner assembly. The flow rates of fuel (LPG/C2H2/Ar) and air were measured using calibrated rotameters. The different volume ratios of the fuel constituents were admitted via three solenoid valves and monitored using a labview program. The axial temperature profiles at different operating conditions were measured using (type S) thermocouple. Flame images were obtained—before and after fluidics insertion—using a high-resolution digital camera. The experimental program aims at identifying and analyzing the changes in flame characteristics resulting from the insertion of fluidics while considering different proportions of the fuel constituents) (including pure LPG, as a reference case). The results obtained indicate the following: it was noticed that in most cases of pure LPG only and other mixtures, the images show increase in the length of the flame and decrease of its luminosity as a result of higher degrees of swirl due to the fluidics insertion while the temperature profiles of the different flames were changed. It was indicated that NOx trend was decreased by 52% while the combustion efficiency was improved by 2.5%.

An Investigation of the Influence of Fluidics Insertion Technique on Acetylene/Argon Gas Additives to LPG on the Turbulent Lean Premixed Flame Characteristics for an EV Burner

2018 ◽  
Author(s):  
Sameh H. Hassan ◽  
Ahmed A. Emara ◽  
Mahmoud A. Elkady
Keyword(s):  
Combustion Efficiency ◽  
Flame Stabilization ◽  
Operating Conditions ◽  
Experimental Program ◽  
Temperature Profiles ◽  
Liquefied Petroleum Gas ◽  
Gas Temperature ◽  
Lean Premixed ◽  
The Impact ◽  
Ev Burner

A series of experiments were performed on a vertical EV burner with a constant coflow air of 873 L /min to generate turbulent lean premixed flow in order to study the impact of the addition of Acetylene/Argon mixture to the liquefied petroleum gas (LPG) on the temperature field and flame structure. The fluidics mechanism was inserted at a fixed position inside the entry section of the EV burner assembly. The flow rates of fuel (LPG/C2H2/ Ar) and air were measured using calibrated rotameters. The different volume ratios of the fuel constituents (at a specified fuel flow rate) were admitted via three solenoid valves at the entry section of each stream prior to mixing and monitored using a labview program. The axial temperature profiles at different operating conditions were measured using a bare wire Pt-Pt -10% Rh (type S) thermocouple of wire diameter 250 μm. Flame images were obtained — before and after fluidics insertion — using a high resolution Canon 6D 20MP digital camera. The selection of the different considerated cases was based on flame stability. The experimental program aims at identifying and analyzing the changes in flame characteristics (flame length, axial profiles of mean gas temperature, NOx concentration and overall combustion efficiency) resulting from the insertion of fluidics while considering different proportions of the fuel constituents) (including pure LPG, as a reference case). In all experiments flame stabilization was ensured. The results obtained indicate the following: it was noticed that in most cases of pure LPG only, and other mixtures the images shows increase in both the length and luminosity of the flame as a result of higher degrees of swirl due to the fluidics insertion while the temperature profiles of the different flames were changed. It was indicated that NOx trend was decreased by 52% while the combustion efficiency was improved by 2.5%.

Can Water Dilution Avoid Flashback On a Hydrogen Enriched Micro Gas Turbine Combustion? – A Large Eddy Simulations Study

2021 ◽  
Author(s):  
Alessio Pappa ◽  
Laurent Bricteux ◽  
Pierre Bénard ◽  
Ward De Paepe
Keyword(s):  
Reaction Rates ◽  
Hydrogen Combustion ◽  
Operating Conditions ◽  
Large Eddy Simulations ◽  
Reference Case ◽  
Large Eddy ◽  
Pure Methane ◽  
The Impact ◽  
Water Dilution ◽  
Air Humidification

Abstract Considering the growing interest in Power-to-Fuel, i.e. production of H2 using electrolysis to store excess renewable electricity, combustion-based technologies still have a role to play in the future of power generation. Hydrogen combustion is well-known to lead to combustion instabilities. The high temperatures and reaction rates can potentially lead to flashback. In the past, combustion air humidification has proven effective to reduce temperatures and reaction rates. Therefore, humidification can open a path to stabilize hydrogen combustion. However, accurate data assessing the impact of humidification on the combustion is still missing for real mGT combustor geometries and operating conditions. This paper presents a comparison between pure methane and hydrogen enriched methane/air combustions, with and without air humidification, in a typical mGT combustion chamber (Turbec T100) using Large Eddy Simulations analysis. In a first step, the necessary minimal water dilution, to reach stable combustion with hydrogen, was assessed using a 1D approach. The one-dimensional unstretched laminar flame is computed for both pure methane (reference case) and hydrogen enriched cases. The results of this comparison show that the same level of flame speed as in the reference case can be reached by adding 10% (in mass fraction) of water. In a second step, high fidelity LES on the 3D geometry are performed to show that water dilution helped to lower the temperature and reaction rate of hydrogen at same levels as reference case, and thus prevents flashback, enabling the use of hydrogen blends in the mGT.

Instability Control by Premixed Pilot Flames

2008 ◽  
Author(s):  
Peter Albrecht ◽  
Stefanie Bade ◽  
Arnaud Lacarelle ◽  
Christian Oliver Paschereit ◽  
Ephraim Gutmark
Keyword(s):  
Gas Turbines ◽  
Flame Structure ◽  
Premixed Flames ◽  
Combustion Process ◽  
Operating Conditions ◽  
Combustion Stability ◽  
Pilot Injection ◽  
Acoustic Instabilities ◽  
Flame Behavior ◽  
The Impact

Premixed flames of swirl-stabilized combustors (displaced-half-cone) are susceptible to thermo-acoustic instabilities which should be avoided under all operating conditions in order to guarantee a long service life for both stationary and aircraft gas turbines. The source of this unstable flame behavior can e.g. be found in a transition of the premix flame structure between two stationary conditions that can be easily excited by fuel fluctuations, coherent structures within the flow and other methods. Pilot flames can alleviate this issue by either improving the dynamic stability directly or by sustaining the main combustion process at operating points where instabilities are unlikely. In the present study, the impact of two different premixed pilot injection on the combustion stability is investigated. One of the pilot injector (pilot flame injector, PFI) was located upstream of the recirculation zone at the apex of the burner. The second one was a pilot ring (PR) placed at the burner outlet on the dump plane. A noticeable feature of the pilot injector was that an ignition device allowed for creating pilot premixed flames. The present investigation evidenced that these premixed pilot flames were able to suppress instabilities over a wider fuel/air ratio range than when the conventional premixed pilot injection alone. Furthermore, it was possible to prevent instabilities and maintain the flame burning near the lean blow out when a percentage of the fuel was premixed with air and injected through the pilot ring. In the mean time, NOx emissions were significantly reduced.

Instability Control by Premixed Pilot Flames

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Peter Albrecht ◽  
Stefanie Bade ◽  
Arnaud Lacarelle ◽  
Christian Oliver Paschereit ◽  
Ephraim Gutmark
Keyword(s):  
Gas Turbines ◽  
Flame Structure ◽  
Premixed Flames ◽  
Combustion Process ◽  
Operating Conditions ◽  
Combustion Stability ◽  
Lean Blowout ◽  
Acoustic Instabilities ◽  
Flame Behavior ◽  
The Impact

Premixed flames of swirl-stabilized combustors (displaced half-cone) are susceptible to thermo-acoustic instabilities, which should be avoided under all operating conditions in order to guarantee a long service life for both stationary and aircraft gas turbines. The source of this unstable flame behavior can be found in a transition of the premix flame structure between two stationary conditions that can be easily excited by fuel fluctuations, coherent structures within the flow, and other mechanisms. Pilot flames can alleviate this issue either by improving the dynamic stability directly or by sustaining the main combustion process at operating points where instabilities are unlikely. In the present study, the impact of two different premixed pilot injections on the combustion stability is investigated. One of the pilot injector (pilot flame injector) was located upstream of the recirculation zone at the apex of the burner. The second one was a pilot ring placed at the burner outlet on the dump plane. A noticeable feature of the pilot injector was that an ignition device allowed for creating pilot premixed flames. The present investigation showed that these premixed pilot flames were able to suppress instabilities over a wider fuel/air ratio range than the conventional premixed pilot injection alone. Furthermore, it was possible to prevent instabilities and maintain the flame burning near the lean blowout when a percentage of the fuel was premixed with air and injected through the pilot ring. NOx emissions were significantly reduced.

Truck Tire Operating Temperatures on Flat and Curved Test Surfaces

2005 ◽  
Vol 33 (3) ◽  
pp. 156-178 ◽  
Author(s):  
T. J. LaClair ◽  
C. Zarak
Keyword(s):  
Flat Surface ◽  
Operating Temperature ◽  
Operating Conditions ◽  
Load Pressure ◽  
Truck Tire ◽  
Endurance Testing ◽  
Operating Temperatures ◽  
The Impact ◽  
Tread Rubber ◽  
Cylindrical Test

Abstract Operating temperature is critical to the endurance life of a tire. Fundamental differences between operations of a tire on a flat surface, as experienced in normal highway use, and on a cylindrical test drum may result in a substantially higher tire temperature in the latter case. Nonetheless, cylindrical road wheels are widely used in the industry for tire endurance testing. This paper discusses the important effects of surface curvature on truck tire endurance testing and highlights the impact that curvature has on tire operating temperature. Temperature measurements made during testing on flat and curved surfaces under a range of load, pressure and speed conditions are presented. New tires and re-treaded tires of the same casing construction were evaluated to determine the effect that the tread rubber and pattern have on operating temperatures on the flat and curved test surfaces. The results of this study are used to suggest conditions on a road wheel that provide highway-equivalent operating conditions for truck tire endurance testing.

A NEW WELDING MATERIAL FOR REGENERATION IN THE WELDING TECHNOLOGY BASED ON NICKEL. ANALYSIS OF THE COMPOSITION AND PROPERTIES OF DEFORMABLE HEAT-RESISTANT HIGH-CHROMIUM NICKEL-BASED ALLOYS FOR WELDED PARTS. ANALYSIS OF EXISTING FUELLING STATIONS TYPES AND VEHICLES USING HYDROGEN, HYDROGEN PRODUCTION AND STORING METHODS

2019 ◽  
pp. 43-48
Author(s):  
Ben Nengjun ◽  
Zhou Pengfei ◽  
Oleksandr Labartkava ◽  
Mykhailo Samokhin
Keyword(s):  
Rare Earth ◽  
High Temperature ◽  
Nickel Alloys ◽  
Total Content ◽  
Operating Conditions ◽  
High Temperature Strength ◽  
High Chromium ◽  
Salt Corrosion ◽  
Tcp Phases ◽  
The Impact

This work involves an analysis of high-chromium high-temperature deformable wieldable nickel alloys for use in GTE repair assemblies. It is shown that the alloys EP868 (VZh98) and Haynes 230 can be used in welded assemblies with an operating temperature of 800-1100 °C. The alloys Nimonic 81, Nimonic 91, IN 935, IN 939, and Nicrotan 2100 GT also have a high potential for use in welded assemblies. They are characterized by a combination of good weldability, high-temperature strength, and resistance to scaling. There have been conducted studies on high-temperature salt corrosion of model nickel alloys. They allowed establishing the patterns of the impact of base metal alloying with chromium, aluminum, titanium, cobalt, tungsten, molybdenum, niobium, tantalum and rare earth metals on the critical temperature of the start of salt corrosion Tcor and the alloy mass loss. It has been established that alloys with a moderate concentration (13-16%) of chromium can possess satisfactory hightemperature corrosion resistance (HTC resistance) under the operating conditions of ship GTE. The HTC resistance of CrAl-Ti alloys improves upon reaching the ratio Ti/Al ˃ 1. Meanwhile, the ratio Ti/Al ˂ 1 promotes the formation of corrosion products with low protective properties. The positive effect of tantalum on the HTC resistance of alloys is manifested at higher test temperatures than that of titanium, and the total content of molybdenum and tungsten in alloys is limited by the condition 8Mo2 – 2W2 = 89. The presence of refractory elements stabilizes the strengthening phase and prevents formation of the ɳ-phase. However, their excess promotes formation of the embrittling topologically close packed (TCP) phases and boundary carbides of an unfavorable morphology. Based on the studies of the HTC resistance, there has been identified a class of model high-temperature corrosionresistant nickel alloys with a moderate or high chromium content (30%), Ti/Al ˃ 1, and a balanced content of refractory and rare-earth elements.

Application of vacuum belt press filters for cane mud filtration and performance comparison with rotary filters

2014 ◽  
pp. 298-301 ◽  
Author(s):  
Arnaud Petit
Keyword(s):  
Electricity Consumption ◽  
Performance Comparison ◽  
Operating Conditions ◽  
Vacuum Filter ◽  
Sugar Mill ◽  
Belt Press ◽  
Vacuum Belt ◽  
And Performance ◽  
Mud Filtration ◽  
The Impact

Bois-Rouge factory, an 8000 t/d cane Reunionese sugarcane mill, has fully equipped its filtration station with vacuum belt press filters since 2010, the first one being installed in 2009. The present study deals with this 3-year experience and discusses operating conditions, electricity consumption, performance and optimisation. The comparison with the more classical rotary drum vacuum filter station of Le Gol sugar mill highlights advantages of vacuum belt press filters: high filtration efficiency, low filter cake mass and sucrose content, low total solids content in filtrate and low power consumption. However, this technology needs a mud conditioning step and requires a large amount of water to improve mud quality, mixing of flocculant and washing of filter belts. The impact on the energy balance of the sugar mill is significant. At Bois-Rouge mill, studies are underway to reduce the water consumption by recycling low d.s. filtrate and by dry cleaning the filter belts.

Influence of temperature and humidity on the angle of repose of wood bulk materials

2016 ◽  
Author(s):  
И.В. Бачериков ◽  
Б.М. Локштанов
Keyword(s):  
Field Experiments ◽  
Bulk Material ◽  
Average Particle Size ◽  
Operating Conditions ◽  
Angle Of Repose ◽  
Wood Dust ◽  
Average Particle ◽  
Bulk Materials ◽  
Technical Literature ◽  
The Impact

При проектировании открытых и закрытых хранилищ измельченных сыпучих материалов древесных материалов, таких как щепа и опилки, большое значение имеет угол естественного откоса (статический и динамический) этих материалов. В технической литературе приводятся противоречивые сведения о величине этих углов, что приводит к ошибкам при проектировании складов. В справочных данных не учитываются условия, в которых эксплуатируются емкости для хранения сыпучих материалов, свойства и состояние этих сыпучих материалов. В свою очередь, ошибки при проектировании приводят к проблемам (зависание, сводообразование, «затопление» и т. д.) и авариям при эксплуатации бункеров и силосов на производстве. В статье представлены сведения, посвященные влиянию влажности и температуры на угол естественного откоса сыпучих материалов. На основании лабораторных и натурных экспериментов, проведенных с помощью специально разработанных методик и установок, была скорректирована формула для определения углов естественного откоса (статического и динамического) для измельченных древесных материалов в зависимости от их фракционного и породного состава, влажности (абсолютной и относительной) и температуры. При помощи скорректированной формулы можно определить угол естественного откоса древесных сыпучих материалов со среднегеометрическим размером частицы от 0,5 мм до 15 мм (от древесной пыли до технологической щепы) в различных производственных условиях. Статья может быть полезна проектировщикам при расчете угла наклона граней выпускающей воронки бункеров и силосов предприятий лесной отрасли и целлюлозо-бумажной промышленности. In the design of open and closed storage warehouses chopped wood materials for bulk materials such as wood chips and sawdust, great importance has an angle of repose (static and dynamic) of these materials. In the technical literature are conflicting reports about the magnitude of these angles, which leads to errors in the design of warehouses. In the referencesdoes not take into account the conditions under which operated capacities for storage of bulk materials, and properties and condition of the bulk material. The design errors lead to problems (hanging, arching, «flooding», etc.) and accidents in the operation of hoppers and silos at the mills. The article provides information on the impact of humidity and temperature on the angle of repose of granular materials. On the basis of laboratory and field experiments, conducted with the help of specially developed techniques and facilities has been adjusted formula for determining the angle of repose (static and dynamic) for the shredded wood materials depending on their fractional and species composition, humidity (absolute and relative) and temperature. It is possible, by using the corrected formula, to determine the angle of repose of loose wood materials with average particle size of from 0.5 mm to 15 mm (wood dust to pulpchips) in various operating conditions. The article can be helpful to designers in the calculation of the angle of inclination of the funnel faces produces bunkers and silos forest industries and pulp and paper industry.

scholarly journals Tanning Wastewater Treatment by Ultrafiltration: Process Efficiency and Fouling Behavior

Membranes ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 461
Author(s):  
Fu Yang ◽  
Zhengkun Huang ◽  
Jun Huang ◽  
Chongde Wu ◽  
Rongqing Zhou ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Shear Rate ◽  
Membrane Surface ◽  
Filtration Efficiency ◽  
Operating Conditions ◽  
Process Efficiency ◽  
Transmembrane Pressure ◽  
Leather Industry ◽  
Pore Blocking ◽  
The Impact

Ultrafiltration is a promising, environment-friendly alternative to the current physicochemical-based tannery wastewater treatment. In this work, ultrafiltration was employed to treat the tanning wastewater as an upstream process of the Zero Liquid Discharge (ZLD) system in the leather industry. The filtration efficiency and fouling behaviors were analyzed to assess the impact of membrane material and operating conditions (shear rate on the membrane surface and transmembrane pressure). The models of resistance-in-series, fouling propensity, and pore blocking were used to provide a comprehensive analysis of such a process. The results show that the process efficiency is strongly dependent on the operating conditions, while the membranes of either PES or PVDF showed similar filtration performance and fouling behavior. Reversible resistance was the main obstacle for such process. Cake formation was the main pore blocking mechanism during such process, which was independent on the operating conditions and membrane materials. The increase in shear rate significantly increased the steady-state permeation flux, thus, the filtration efficiency was improved, which resulted from both the reduction in reversible resistance and the slow-down of fouling layer accumulate rate. This is the first time that the fouling behaviors of tanning wastewater ultrafiltration were comprehensively evaluated, thus providing crucial guidance for further scientific investigation and industrial application.

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