Experimental Investigation of a Hollow Cone Spray Using Laser Diagnostics

2014 ◽  
Vol 136 (7) ◽  
Author(s):  
Mithun Das ◽  
Souvick Chatterjee ◽  
Achintya Mukhopadhyay ◽  
Swarnendu Sen
Keyword(s):  
Gas Turbines ◽  
High Speed ◽  
Laser Diagnostics ◽  
Laser Sheet ◽  
Droplet Diameter ◽  
Injection Pressure ◽  
Diameter Distribution ◽  
Hollow Cone ◽  
Wide Range ◽  
Hollow Cone Spray

Atomization of fuel is a key integral part for efficient combustion in gas turbines. This demands a thorough investigation of the spray characteristics using innovative and useful spray diagnostics techniques. In this work, an experimental study is carried out on a commercial hollow cone nozzle (Lechler) using laser diagnostics techniques. A hollow cone spray is useful in many applications because of its ability to produce fine droplets. But apart from the droplet diameter, the velocity field in the spray is also an important parameter to monitor and has been addressed in this work. Kerosene is used as the test fuel, which is recycled using a plunger pump providing a variation in the injection pressure from 100 to 300 psi. An innovative diagnostic technique used in this study is through illumination of the spray with a continuous laser sheet and capturing the same with a high speed camera. A ray of a laser beam is converted to a planer sheet using a lens combination which is used to illuminate a cross section of the hollow cone spray. This provides a continuous planar light source which allows capturing high speed images at 285 fps. The high speed images thus obtained are processed to understand the nonlinearity associated with disintegration of the spray into fine droplets. The images are shown to follow a fractal representation and the fractal dimension is found to increase with rise in injection pressure. Also, using PDPA, the droplet diameter distribution is calculated at different spatial and radial locations at a wide range of pressure.

Experimental Investigation of a Hollow Cone Spray Using Laser Diagnostics

2013 ◽  
Author(s):  
Mithun Das ◽  
Souvick Chatterjee ◽  
Swarnendu Sen ◽  
Achintya Mukhopadhyay
Keyword(s):  
Gas Turbines ◽  
High Speed ◽  
Laser Diagnostics ◽  
Laser Sheet ◽  
Droplet Diameter ◽  
Injection Pressure ◽  
Diameter Distribution ◽  
Hollow Cone ◽  
Wide Range ◽  
Hollow Cone Spray

Atomization of fuel is a key integral part for efficient combustion in gas turbines. This demands a thorough investigation of the spray characteristics using innovative and useful spray diagnostics techniques. In this work, an experimental study is carried out on commercial hollow cone nozzle (Lechler) using laser diagnostics techniques. A hollow cone spray is useful in many applications because of its ability to produce fine droplets. But apart from the droplet diameter, the velocity field in the spray is also an important parameter to monitor and has been addressed in this work. Kerosene is used as the test fuel which is recycled using a plunger pump providing a variation in the injection pressure from 100psi to 300psi. An innovative diagnostic technique used in this study is through illumination of the spray with a continuous laser sheet and capturing the same with a high speed camera. A ray of laser beam is converted to a planer sheet using a lens combination which is used to illuminate a cross section of the hollow cone spray. This provides a continuous planar light source which allows capturing high speed images at 285 fps. The high speed images, thus obtained are processed to understand the non-linearity associated with disintegration of the spray into fine droplets. The images are shown to follow a fractal representation and the fractal dimension is found to increase with rise in injection pressure. Also, using PDPA, the droplet diameter distribution is calculated at different spatial and radial locations at wide range of pressure.

Boundary Layer Flashback Limits of Hydrogen-Methane-Air Flames in a Generic Swirl Burner at Gas Turbine Relevant Conditions

2020 ◽  
Author(s):  
Dominik Ebi ◽  
Peter Jansohn
Keyword(s):  
Boundary Layer ◽  
Gas Turbine ◽  
Wall Temperature ◽  
Gas Turbines ◽  
High Speed ◽  
Cooling System ◽  
Atmospheric Conditions ◽  
Preheat Temperature ◽  
Swirl Burner ◽  
Wide Range

Abstract Operating stationary gas turbines on hydrogen-rich fuels offers a pathway to significantly reduce greenhouse gas emissions in the power generation sector. A key challenge in the design of lean-premixed burners, which are flexible in terms of the amount of hydrogen in the fuel across a wide range and still adhere to the required emissions levels, is to prevent flame flashback. However, systematic investigations on flashback at gas turbine relevant conditions to support combustor development are sparse. The current work addresses the need for an improved understanding with an experimental study on boundary layer flashback in a generic swirl burner up to 7.5 bar and 300° C preheat temperature. Methane-hydrogen-air flames with 50 to 85% hydrogen by volume were investigated. High-speed imaging was applied to reveal the flame propagation pathway during flashback events. Flashback limits are reported in terms of the equivalence ratio for a given pressure, preheat temperature, bulk flow velocity and hydrogen content. The wall temperature of the center body along which the flame propagated during flashback events has been controlled by an oil heating/cooling system. This way, the effect any of the control parameters, e.g. pressure, had on the flashback limit was de-coupled from the otherwise inherently associated change in heat load on the wall and thus change in wall temperature. The results show that the preheat temperature has a weaker effect on the flashback propensity than expected. Increasing the pressure from atmospheric conditions to 2.5 bar strongly increases the flashback risk, but hardly affects the flashback limit beyond 2.5 bar.

Experimental Validation of Methods Providing Boundary Conditions to Simulate the Evaporation Process of Water Injected Into High Speed Air Flow

2013 ◽  
Author(s):  
P. S. Nagabhushan ◽  
A. Rossetti ◽  
B. Barabas ◽  
J. P. Schnitzler ◽  
A. Kefalas ◽  
...  
Keyword(s):  
Experimental Data ◽  
Boundary Conditions ◽  
Gas Turbines ◽  
High Speed ◽  
Air Flow ◽  
Computational Cost ◽  
Spray Angle ◽  
Diameter Distribution ◽  
Particle Injection ◽  
Lagrange Approach

Water injection into a high speed air flow has been recently investigated by many scientists and is still an important field of research in gas turbine technology. To study the behavior of droplets in gas turbines, expensive experimental tests and their validation with analytical and Computational Fluid Dynamics (CFD) models are necessary. The Euler-Lagrange approach can be used to tackle these problems due to their capability in tracking particles along the domain, relative ease in formulating and applying them to the current industrial problems in terms of acceptable computational cost. However, providing spray boundary conditions using Euler-Lagrange approach is quite challenging because the spray pattern depends upon various parameters like spray angle, velocity, diameter distribution etc. In this paper, to obtain these parameters, two different approaches are described. The first approach depends on an analytical model for velocity and spray angle injection conditions and the second approach depends on an Euler free surface simulation. For diameter distribution, Rosin Rammler distribution function and experimental data are used. When combined together these lead to four particle injection conditions. The results achieved from all the four cases are compared with the experimental data of water droplet evaporation in a high speed air flow obtained from a hot air test rig operating at conditions of real gas turbines.

scholarly journals Influence of Spray Nozzle Operating Parameters on the Fogging Process Implemented to Prevent the Spread of SARS-CoV-2 Virus

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4280
Author(s):  
Waldemar Fedak ◽  
Roman Ulbrich ◽  
Grzegorz Ligus ◽  
Marek Wasilewski ◽  
Szymon Kołodziej ◽  
...  
Keyword(s):  
Droplet Diameter ◽  
Diameter Distribution ◽  
Operating Parameters ◽  
Two Phase ◽  
Weighting Method ◽  
Spray Cone ◽  
Air Supply ◽  
Wide Range ◽  
Flow Intensity ◽  
Pressure Swirl

This article reports the results of a study into the effect of operating parameters on the occurrence and course of gas–liquid two-phase phenomena during the fogging process carried out with the use of a conical pressure-swirl nozzle. Four alternatives of the stub regulation angles and four values of pressure of air supply to the nozzle were tested as part of the current research. The range of the investigated variables was common for the operation of fumigators used to prevent the spread of SARS-CoV-2 virus. The liquid flow rate (weighting method), the field of velocity, and turbulent flow intensity factor, as well as velocity profiles over the section of 1 m from the nozzle were determined using the particle image velocimetry (PIV) technique. The obtained results were correlated with the measurements of the diameters of spray droplets using the laser light scattering (LLS) technique. On the basis of this research, a dependence between the nozzle parameters and the spray cone pattern was identified in terms of dynamics and droplet diameter distribution. As a result of the research, a wide range of parameters were identified in which the fogging process was carried out in a stable and repeatable manner. There were exceptions to this rule only in the cases when there was a deficiency of the liquid necessary to generate a two-phase mixture.

A New Type Laser Imaging System of Underwater Wake Bubbles

2014 ◽  
Vol 543-547 ◽  
pp. 2505-2508
Author(s):  
Xi Zhan Liu ◽  
Yan Bo Xue
Keyword(s):  
High Speed ◽  
Imaging System ◽  
Laser Sheet ◽  
High Speed Photography ◽  
Test Results ◽  
Laser Imaging ◽  
Technical Requirements ◽  
Wide Range ◽  
New Type ◽  
Wake Zone

Considering the difficulties in the wake bubbles imaging, a wake bubbles measurement system was presented based on the combination of high speed photography and laser sheet scanning technology. In this system, laser sheet was used to illuminate the wake zone to avoid the image stacking of bubbles. Because the particle size of bubbles was in a wide range (10~500um), three switchable magnification lenses were designed for the bubbles imaging. the test results show that the image quality is good and this system satisfies technical requirements.

Velocity and Droplet Diameter Distributions of Reacting N-Heptane Sprays at Varied Boundary Conditions in a Generic Gas Turbine Combustor

2010 ◽  
Author(s):  
Michael Hage ◽  
Jan Bru¨bach ◽  
Andreas Dreizler
Keyword(s):  
Boundary Conditions ◽  
Gas Turbines ◽  
Swirling Flow ◽  
Laser Diagnostics ◽  
Droplet Diameter ◽  
Measurement Techniques ◽  
Operating Conditions ◽  
Chamber Pressure ◽  
Inlet Temperature ◽  
Diameter Distributions

In addition to a previous isothermal study, the present work reports on reacting swirling flow fields and droplet diameter distributions. The employed combustion chamber enabled optical access from three sides allowing the application of laser based measurement techniques. It is equipped with an airblast atomizer nozzle typical for gas turbines. The parameters of the boundary conditions were varied to such an extent that laser diagnostics were feasible. The chamber pressure and the inlet temperature were 2–3 bar and 300–350°C, respectively. The analysis of the spray droplets were performed by two velocity component phase Doppler anemometry (PDA). The measurements allowed for the investigation of axial and radial droplet velocities, Sauter mean diameter (SMD) distributions and an estimation of the volume flow rates. Comparisons of the different operating conditions and the influence of the parameters are given in the discussion.

scholarly journals Quantitative analysis of dribble volumes and rates using three-dimensional reconstruction of X-ray and diffused back-illumination images of diesel sprays

2019 ◽  
Vol 21 (1) ◽  
pp. 43-54 ◽  
Author(s):  
Vitaliy Sechenyh ◽  
Daniel J Duke ◽  
Andrew B Swantek ◽  
Katarzyna E Matusik ◽  
Alan L Kastengren ◽  
...  
Keyword(s):  
High Speed ◽  
Imaging System ◽  
Process Analysis ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Injection Pressure ◽  
X Ray ◽  
Temperature Conditions ◽  
Processing Approach ◽  
Wide Range

Post-injection fuel dribble is known to lead to incomplete atomisation and combustion due to the release of slow-moving, and often surface-bound, liquid fuel after the end of injection. This can have a negative effect on engine emissions, performance and injector durability. To better quantify this phenomenon, we developed an image-processing approach to measure the volume of ligaments produced during the end of injection. We applied our processing approach to an Engine Combustion Network ‘Spray B’ 3-hole injector, using datasets from 220 injections generated by different research groups, to decouple the effect of gas temperature and pressure on the fuel dribble process. High-speed X-ray phase-contrast images obtained at room temperature conditions (297 K) at the Advanced Photon Source at Argonne National Laboratory, together with diffused back-illumination images captured at a wide range of temperature conditions (293–900 K) by CMT Motores Térmicos were analysed and compared quantitatively. We found a good agreement between image sets obtained by Argonne National Laboratory and CMT Motores Térmicos using different imaging techniques. The maximum dribble volume within the field of view of the imaging system and the mean rate of fuel dribble were considered as characteristic parameters of the fuel dribble process. Analysis showed that the absolute mean dribble rate increases with temperature when injection pressure is higher than 1000 bar and slightly decreases at high injection pressures (>500 bar) when temperature is close to 293 K. Larger maximum volumes of the fuel dribble were observed at lower gas temperatures (∼473 K) and low gas pressures (<30 bar), with a slight dependence on injection pressure.

A New Experimental Facility to Investigate Combustor–Turbine Interactions in Gas Turbines With Multiple Can Combustors

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
S. Luque ◽  
V. Kanjirakkad ◽  
I. Aslanidou ◽  
R. Lubbock ◽  
B. Rosic ◽  
...  
Keyword(s):  
Gas Turbines ◽  
High Speed ◽  
Cooling System ◽  
Experimental Facility ◽  
Blow Down ◽  
Wide Range ◽  
Flow Interactions ◽  
Inlet Swirl ◽  
Nozzle Guide ◽  
Cooling Air

This paper describes a new modular experimental facility that was purpose-built to investigate flow interactions between the combustor and first stage nozzle guide vanes (NGVs) of heavy duty power generation gas turbines with multiple can combustors. The first stage turbine NGV is subjected to the highest thermal loads of all turbine components and therefore consumes a proportionally large amount of cooling air that contributes detrimentally to the stage and cycle efficiency. It has become necessary to devise novel cooling concepts that can substantially reduce the coolant air requirement but still allow the turbine to maintain its aerothermal performance. The present work aims to aid this objective by the design and commissioning of a high-speed linear cascade, which consists of two can combustor transition ducts and four first stage NGVs. This is a modular nonreactive air test platform with engine realistic geometries (gas path and near gas path), cooling system, and boundary conditions (inlet swirl, turbulence level, and boundary layer). The paper presents the various design aspects of the high pressure (HP) blow down type facility, and the initial results from a wide range of aerodynamic and heat transfer measurements under highly engine realistic conditions.

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