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

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.

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An Experimental Way of Assessing the Application Potential of Emulsified Palm Biodiesel Toward Alternative to Diesel

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4025479 ◽

2013 ◽

Vol 136 (2) ◽

Cited By ~ 13

Author(s):

Biplab K. Debnath ◽

Ujjwal K. Saha ◽

Niranjan Sahoo

Keyword(s):

Diesel Engine ◽

Compression Ratio ◽

Droplet Diameter ◽

Stability Study ◽

Pollutant Emissions ◽

Operating Parameters ◽

Injection Timing ◽

Two Phase ◽

Full Load ◽

Phase Water

Amid various methods available to reduce pollutant emissions and to improve performance and combustion characteristics of a diesel engine, emulsified fuel seems to be promising. However, because of its different properties from diesel, a biodiesel emulsion is incompetent to provide standard diesel performance. Once combusted in a diesel engine; the proper adjustment of engine operating parameters with the presence of “micro-explosion” may amend the performance of a biodiesel emulsion run engine. In order to realize this fact, a comprehensive study has been carried out in a variable compression ratio diesel engine running with two-phase water in a palm biodiesel emulsion. The engine operating parameters studied and optimized are compression ratio (CR), injection timing (IT), and load. The water emulsions of palm oil methyl ester (WIP) with various specifications have been prepared by commercially available surfactants with appropriate HLB values. Water quantity (5% and 10%), surfactant quantity (1%, 2%, and 3%), and HLB values (4.3, 5, and 6) are the parameters optimized to attain the stable WIP by means of mean droplet diameter measurement and stability study. The optimized WIP of 5% water, 3% surfactant of 6 HLB is then tested in a diesel engine at varying CR (17, 17.5, and 18) and IT (20, 23, and 28 deg BTDC). For each of the combinations of CR and IT, the load has been varied from idling conditions to full load (12 kg) with an increment of 20% (2.4 kg) and 110% (13.2 kg) of full load. The results are analyzed in the form of performance, combustion, and emission parameters with respect to the baseline diesel run (CR = 17.5 and IT = 23 deg BTDC).

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Experimental Investigation of a Hollow Cone Spray Using Laser Diagnostics

ASME 2013 Gas Turbine India Conference ◽

10.1115/gtindia2013-3709 ◽

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.

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Semi-Empirical Correlation to Predict the Sauter Mean Diameter of the Pressure-Swirl Atomizer

Volume 1: Advances in Aerodynamics ◽

10.1115/imece2013-62907 ◽

2013 ◽

Author(s):

Wei Xiao ◽

Yong Huang

Keyword(s):

Weber Number ◽

Droplet Diameter ◽

Empirical Correlation ◽

Sauter Mean Diameter ◽

Operation Condition ◽

Wide Range ◽

Swirl Atomizer ◽

Pressure Swirl ◽

Semi Empirical ◽

Pressure Swirl Atomizer

In this study, experiments have been performed to investigate effects of pressure-swirl atomizer geometry on SMD. Different pressure-swirl atomizers were applied to study the effect of geometry on the SMD. Based on the experimental results, an empirical correlation was obtained to relate SMD with the Weber number characterized by film thickness. Meanwhile, a semi-empirical model which was improved from the surface wave breakup theory was established to predict the SMD of pressure-swirl atomizers. The model provides the droplet diameter as a function of atomizer geometry, operation condition and liquid properties. It is proved that the model is qualified for predicting SMD of pressure-swirl atomizers among wide range.

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Experimental Investigation of a Hollow Cone Spray Using Laser Diagnostics

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4026549 ◽

2014 ◽

Vol 136 (7) ◽

Cited By ~ 1

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.

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Visualization of Entrainment and Surface Behavior of High Speed Air Jet Blowing Out From a Hole to Stagnant Water

Volume 5: Fusion Engineering; Student Paper Competition; Design Basis and Beyond Design Basis Events; Simple and Combined Cycles ◽

10.1115/icone20-power2012-55068 ◽

2012 ◽

Author(s):

Kohei Nago ◽

Yasuo Koizumi ◽

Akihiro Uchibori ◽

Hiroyuki Ohshima

Keyword(s):

High Speed ◽

Two Phase Flow ◽

Droplet Diameter ◽

Video Camera ◽

Diameter Distribution ◽

Phase Flow ◽

Stagnant Water ◽

Two Phase ◽

Air Jet ◽

Jet Blowing

A two dimensional air jet was blown out from a nozzle into water in a thin vessel. The behavior of the interface between water and the air jet and also the air jet were recorded with a high speed video camera. Filament-like ears and wisps pulled-out from the wavy water surface were noticed in the recorded photos. Droplets are formed from these. Droplet diameters were obtained from the recorded photos. As the air velocity increased, the number of droplets created by the air jet increased lineally and the smaller droplets increased. The correlation for the droplet diameter distribution developed for the annular dispersed two-phase flow in a pipe predicted well the present results. The correlations for the droplet diameter developed for the annular dispersed two-phase flow in a pipe and for the jet blowing out from the stagnant water pool considerably underpredict the experimental results.

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Developing Effervescent Atomisation for Alternative Fuels

Volume 1: Aircraft Engine; Ceramics; Coal, Biomass and Alternative Fuels; Controls, Diagnostics and Instrumentation ◽

10.1115/gt2012-69777 ◽

2012 ◽

Author(s):

Dancho D. Konstantinov ◽

Philip J. Bowen ◽

Richard Marsh ◽

Peter J. Kay ◽

Andrew P. Crayford ◽

...

Keyword(s):

Literature Review ◽

Alternative Fuels ◽

Combustion Process ◽

Volume Ratio ◽

Industrial Applications ◽

Quality Data ◽

Operating Parameters ◽

Extensive Literature ◽

Two Phase ◽

Wide Range

A wide range of atomiser types have been developed for industrial applications — such as rotary, pressure, air-assist and air-blast atomisers. Each type works on the principle of applying mechanical or kinetic energy to disintegrate a jet or sheet of liquid fuel, in preparation for combustion. The aim is to sufficiently increase the surface area to volume ratio of the fuel and presents it in a form suitable for a consistent combustion process. Traditional liquid fuels, such as fossil fuels, have been employed for some decades and combustion systems (and atomisers) have been optimised for their use. However, combustion engineers are being increasingly forced to consider the use of alternative, biologically-derived hydrocarbon fuels. Such fuels often have very different viscosities, densities and surface tensions or possess complex, non-linear properties when compared to conventional fuels. Effervescent atomisation is a promising two-phase atomisation technique offering potential improvements in fluid atomisation quality and reductions in fluid operating pressures. It appears particularly well suited to the atomisation of viscous fuels such as biofuels; this applicability to alternative fuels has led to a renewed interest in the method. After an extensive literature review of the current state of this technology [1] an adjustable geometry effervescent atomiser was designed, built and studied at the Cardiff School of Engineering. Water and air were used as the operating fluids. The sprays produced by the atomiser were characterised using a Phase Doppler Anemometry (PDA) system which allowed for simultaneous real-time droplet size and velocity data to be obtained. High quality data was achieved with data rates over 10 kHz and validation rates over 90% in 2-D LDA mode in the high density sprays. A PDA probe designed for dense spray applications was utilised. A number of important operating parameters identified during the literature review phase can be altered on the atomiser, and their effects on fuel spray quality investigated. The operating parameters investigated in this manner included air-to-liquid by mass ratio (ALR), pressure drop as well as a range of geometric parameters. This paper discusses and analyses the influence of ALR on the quality of atomisation and the associated two-phase flow field. Comparisons are made with previous studies and correlations, using earlier versions of the hardware or alternative techniques. Ongoing work will assess and optimise the performance of simulated biofuels mixtures.

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Two-Phase Flow Phenomena in Gas Turbine Compressors with a Focus on Experimental Investigation of Trailing Edge Disintegration

Aerospace ◽

10.3390/aerospace8040091 ◽

2021 ◽

Vol 8 (4) ◽

pp. 91

Author(s):

Adrian Schlottke ◽

Bernhard Weigand

Keyword(s):

Experimental Investigation ◽

Gas Turbine ◽

Gas Turbines ◽

Two Phase Flow ◽

Droplet Diameter ◽

Air Flow ◽

Diameter Distribution ◽

Phase Flow ◽

Trailing Edge ◽

Two Phase

Two-phase flow in gas turbine compressors occurs, for example, at heavy rain flight condition or at high-fogging in stationary gas turbines. The liquid dynamic processes are independent of the application. An overview on the processes and their approach in literature is given. The focus of this study lies on the experimental investigation of the trailing edge disintegration. In the experiments, shadowgraphy is used to observe the disintegration of a single liquid rivulet with constant liquid mass flow rate at the edge of a thin plate at different air flow velocities. A two side view enables calculating droplet characteristics with high accuracy. The results show the asymptotic behavior of the ejected mean droplet diameters and the disintegration period. Furthermore, it gives a detailed insight into the droplet diameter distribution and the spreading of the droplets perpendicular to the air flow.

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Electron sources: Past, present, and future

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100149659 ◽

1993 ◽

Vol 51 ◽

pp. 764-765

Author(s):

David C Joy

Keyword(s):

Glass Tube ◽

Source Size ◽

Electron Gun ◽

Operating Parameters ◽

Operational Parameters ◽

Electron Sources ◽

Difficult Decision ◽

Probe Size ◽

Wide Range ◽

Overall Performance

The electron source is the most important component of the Scanning electron microscope (SEM) since it is this which will determine the overall performance of the machine. The gun performance can be described in terms of quantities such as its brightness, its source size, its energy spread, and its stability and, depending on the chosen application, any of these factors may be the most significant one. The task of the electron gun in an SEM is, in fact, particularly difficult because of the very wide range of operational parameters that may be required e.g a variation in probe size of from a few angstroms to a few microns, and a probe current which may go from less than a pico-amp to more than a microamp. This wide range of operating parameters makes the choice of the optimum source for scanning microscopy a difficult decision.Historically, the first step up from the sealed glass tube ‘cathode ray generator’ was the simple, diode, tungsten thermionic emitter.

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