scholarly journals Spraying of Viscous Liquids: Influence of Fluid-Mixing Mechanism on the Performance of Internal-Mixing Twin-Fluid Atomizers

2020 ◽  
Vol 10 (15) ◽  
pp. 5249
Author(s):  
Marek Mlkvik ◽  
Jan Jedelsky ◽  
Heike P. Karbstein ◽  
Volker Gaukel
Keyword(s):  
Optical Diffraction ◽  
Liquid Fuels ◽  
Liquid Viscosity ◽  
Two Phase ◽  
Internal Mixing ◽  
Mixing Chamber ◽  
Wide Range ◽  
Effervescent Atomizer ◽  
The Common ◽  
Jet Nozzle

The thermal usage of liquid fuels implies their combustion, which is a process strongly influenced by the performance of the atomizer, which disrupts the fuel into drops of the required sizes. The spray quality of the twin-fluid atomizers with internal mixing (IM-TFA) is primarily influenced by the two-phase flow pattern inside the mixing chamber. We studied the performance of the four types of the IM-TFA nozzles by the optical diffraction system (Malvern Spraytec) to answer the question of how the mixing chamber design influences the spray quality at low atomizing gas consumption. We tested the effervescent atomizer in outside-in-liquid (OIL) and outside-in-gas (OIG) configurations, the Y-jet nozzle and new nozzle design, and the CFT atomizer when spraying model liquids with the viscosities comparable to the common fuels (μ=60and143 mPa· s). We found that the effervescent atomizer performance was strongly influenced by the configuration of the inlet ports. Although the OIL configuration provided the best spray quality (D32 = 72 μm), with the highest efficiency (0.16%), the OIG nozzle was characterized by unstable work and poor spray quality. Both the devices were sensitive to liquid viscosity. The Y-jet nozzle provided a stable performance over the liquid viscosity spectrum, but the spray quality and efficiency were lower than for the OIL nozzle. Our findings can be used to improve the performance of the common IM-TFA types or to design new atomizers. The results also provide an overview of the tested atomizers’ performances over the wide range of working conditions and, thus, help to define the application potential of the tested nozzle designs.

Investigation of Two-Phase Flow in an Effervescent Atomizer

2014 ◽  
Author(s):  
Mona Hassanzadeh Jobehdar ◽  
Aly H. Gadallah ◽  
Kamran Siddiqui ◽  
Wajid A. Chishty
Keyword(s):  
Internal Combustion Engines ◽  
Two Phase Flow ◽  
Separation Bubble ◽  
Phase Flow ◽  
Two Phase ◽  
Chamber Length ◽  
Flat Base ◽  
Mixing Chamber ◽  
Wide Range ◽  
Effervescent Atomizer

Aerated-liquid atomization, also called “effervescent atomization”, is a technique that has a wide range of applications such as gas turbine combustors, internal combustion engines, furnaces and burners, and pharmaceutical sprays. We report on an experimental study conducted to investigate the two-phase flow in an Effervescent atomizer. A novel aerator tube base was implemented and tested. It is observed that the novel configuration suppresses the separation bubble at the trailing edge and results in more uniform and smaller bubbles compared to the standard flat base aerator. It has been found that the more uniform and smaller bubbles are generated as the mixing chamber length is reduced. It is concluded that by using a conical base aerator and by reducing the mixing chamber length, the spray steadiness and the atomization process can be significantly improved.

scholarly journals Unsteady Behaviour of the Effervescent Atomizer

2020 ◽  
Vol 328 ◽  
pp. 01008
Author(s):  
Marek Mlkvik
Keyword(s):  
Plug Flow ◽  
Liquid Fuels ◽  
Viscous Liquids ◽  
Internal Mixing ◽  
Viscosity Increase ◽  
Mixing Chamber ◽  
Effervescent Atomizer ◽  
Fine Spray ◽  
Gas Consumption ◽  
Working Parameters

The effervescent atomizer is a well-established type of the twin-fluid nozzle with internal mixing of fluids. It is popular for the ability to process highly viscous liquids, such as liquid fuels, into a fine spray with low gas consumption. This study aims to investigate the performance of the effervescent nozzle when spraying the liquids with a viscosity up to 308 mPa·s. The working parameters of the nozzle were defined by the mass flows ratio of the gas to the liquid (GLR =2.5 to 20 %) and the gas pressure at the nozzle inlet (Δp = 0.14 MPa). The spray quality was investigated by the laser diffraction system, measuring the spray drop sizes. The investigated nozzle was able to atomize all of the model liquids. However, the liquid viscosity increase led to the need to operate the nozzle with the larger gas consumption. The minimum GLR for the spraying of the liquid with the viscosity 308 mPa·s was 10 %, while the less viscous liquid (60 mPa·s) was processed with the GLR = 2.5 %. It was observed that the spray quality was, at the low GLRs, lowered by unstable nozzle work, caused by the presence of the plug flow in the mixing chamber of the atomizer.

EFFECT OF THE INNER TWO-PHASE FLOW ON THE PERFORMANCE OF AN INDUSTRIAL TWIN-FLUID NOZZLE WITH AN INTERNAL MIXING CHAMBER

2009 ◽  
Vol 19 (9) ◽  
pp. 873-884 ◽  
Author(s):  
German Ferreira ◽  
Felix Barreras ◽  
Antonio Lozano ◽  
Juan Antonio Garcia ◽  
Eduardo Lincheta
Keyword(s):  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Internal Mixing ◽  
Mixing Chamber

scholarly journals Numerical simulation of bioaerosol particle exposure assessment in office environment from MVAC systems

2017 ◽  
Vol 10 (2) ◽  
pp. 59-71 ◽  
Author(s):  
HC Yu ◽  
KW Mui ◽  
LT Wong
Keyword(s):  
Ventilation Rate ◽  
Two Phase ◽  
Maintenance Strategies ◽  
Office Environment ◽  
Particle Exposure ◽  
Mixing Chamber ◽  
Wide Range ◽  
Ventilation Strategies ◽  
Cooling Coils ◽  
Ventilation Rates

Bioaerosol (i.e. biological aerosol) exposures in the office environment are associated with a wide range of health effects. The potential bioaerosol emission from mechanical ventilation and air conditioning (MVAC) systems can endanger the building occupants in office, especially as over 90% of commercial buildings in Hong Kong that are equipped with MVAC systems, due to the microbial growths inside MVAC systems, such as cooling coils and mixing chamber, were reported. This study evaluated the exposure risk of the bioaerosol emission from the MVAC systems to the building occupants. A two-phase flow computational fluid dynamics approach was adopted to simulate the emission, dispersion, deposition, and exhaustion of bioaerosol particles from the MVAC systems in a typical office cubicle by altering the ventilation strategies with four ventilation rates, four emission concentrations, and two microorganism species. The results reported that about 5% contribution of concentration level from the MVAC system including the ventilation rate is sufficient to dilute the biocontainment. This study suggested the importance of the maintenance strategies of MVAC systems for minimizing bioaerosol exposures in offices.

Three-Dimensional Simulation of Liquid-Solid Two-Phase Flow Inside the Abrasive Water Jet Nozzle

2007 ◽  
Vol 329 ◽  
pp. 329-334
Author(s):  
Chuan Zhen Huang ◽  
Rong Guo Hou ◽  
Jun Wang ◽  
X.Y. Lu ◽  
Hong Tao Zhu
Keyword(s):  
Velocity Field ◽  
Cross Section ◽  
Three Dimensional ◽  
Flow Speed ◽  
Water Jet ◽  
Abrasive Water Jet ◽  
Two Phase ◽  
Mixing Chamber ◽  
Jet Nozzle ◽  
Dimensional Simulation

Three dimensional simulation of the velocity field of solid-liquid two-phase flow inside the abrasive water jet nozzle was studied by the computational fluid dynamics software (CFD). The complicated velocity field and vectorgraph of the flow in the abrasive water jet nozzle was obtained. In the course of the simulation, the Syamlal-O’Brien model was used to decide the inter-phase drag exchange coefficient. The velocity vectorgraph simulation results indicate that the highest flow speed is occurred at the inlet of the mixing chamber and the flow speed is gradually decreased along the direction of the nozzle axis and got to the lowest speed at the outlet of the nozzle. And also the flow speed in the cross section of the mixing chamber is gradually reduced along the radial direction of the cross section and got to the lowest speed in the verge of the chamber. The comparison of simulation result for the velocity field of water and abrasive exhibits that the velocity of water in the mixing chamber is three or four times higher than that of abrasive.

Recent Applications of High Resolution Electron Microscopy to Crystalline Arrays of Virus Particles

1978 ◽  
Vol 36 (3) ◽  
pp. 470-482 ◽  
Author(s):  
R.W. Horne
Keyword(s):  
Electron Microscopy ◽  
Image Processing ◽  
Analytical Techniques ◽  
Staining Technique ◽  
High Resolution Electron Microscopy ◽  
Optical Diffraction ◽  
Full Potential ◽  
Virus Particles ◽  
Resolution Electron ◽  
Wide Range

The technique of surrounding virus particles with a neutralised electron dense stain was described at the Fourth International Congress on Electron Microscopy, Berlin 1958 (see Home & Brenner, 1960, p. 625). For many years the negative staining technique in one form or another, has been applied to a wide range of biological materials. However, the full potential of the method has only recently been explored following the development and applications of optical diffraction and computer image analytical techniques to electron micrographs (cf. De Hosier & Klug, 1968; Markham 1968; Crowther et al., 1970; Home & Markham, 1973; Klug & Berger, 1974; Crowther & Klug, 1975). These image processing procedures have allowed a more precise and quantitative approach to be made concerning the interpretation, measurement and reconstruction of repeating features in certain biological systems.

Comprehensive Comparisons of a Two-Phase Flow Model with a Wide Range of Conditions

2006 ◽  
Author(s):  
Haijiang Liu ◽  
Shinji Sato
Keyword(s):  
Flow Model ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Wide Range

A Comparison of Physiological Demand between Self-Propelled and Motorized Treadmill Exercise

2018 ◽  
Vol 7 (4) ◽  
pp. 13-21
Author(s):  
Todd Backes ◽  
Charlene Takacs
Keyword(s):  
Respiratory Exchange Ratio ◽  
Treadmill Exercise ◽  
Cardiopulmonary Exercise Testing ◽  
Mean Value ◽  
The Self ◽  
Mixing Chamber ◽  
Wide Range ◽  
The Subject ◽  
The Mean ◽  
Computer Controlled

There are a wide range of options for individuals to choose from in order to engage in aerobic exercise; from outdoor running to computer controlled and self-propelled treadmills. Recently, self-propelled treadmills have increased in popularity and provide an alternative to a motorized treadmill. Twenty subjects (10 men, 10 women) ranging in age from 19-23 with a mean of 20.4 ± 0.8 SD were participants in this study. The subjects visited the laboratory on three occasions. The purpose of the first visit was to familiarize the subject with the self-propelled treadmill (Woodway Curve 3.0). The second visit, subjects were instructed to run on the self-propelled treadmill for 3km at a self-determined pace. Speed data were collected directly from the self-propelled treadmill. The third visit used speed data collected during the self-propelled treadmill run to create an identically paced 3km run for the subjects to perform on a motorized treadmill (COSMED T150). During both the second and third visit, oxygen consumption (VO2) and respiratory exchange ratio (R) data were collected with COSMED’s Quark cardiopulmonary exercise testing (CPET) metabolic mixing chamber system. The VO2 mean value for the self-propelled treadmill (44.90 ± 1.65 SE ml/kg/min) was significantly greater than the motorized treadmill (34.38 ± 1.39 SE ml/kg/min). The mean R value for the self-propelled treadmill (0.91 ± 0.01 SE) was significantly greater than the motorized treadmill (0.86 ± 0.01 SE). Our study demonstrated that a 3km run on a self-propelled treadmill does elicit a greater physiological response than a 3km run at on a standard motorized treadmill. Self-propelled treadmills provide a mode of exercise that offers increased training loads and should be considered as an alternative to motorized treadmills.

COPPER ALLOY No. 268

Alloy Digest ◽  
1976 ◽  
Vol 25 (2) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Copper Alloy ◽  
Cold Working ◽  
Heat Treating ◽  
Zinc Alloy ◽  
Good Resistance ◽  
Wide Range ◽  
Copper Zinc ◽  
The Common ◽  
Cold Worked

Abstract Copper Alloy No. 268 is a copper-zinc alloy with excellent cold-working properties and good resistance to corrosion. It can be cold worked by all the common fabrication processes and has a wide range of applications. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength as well as fatigue. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Cu-306. Producer or source: Brass mills.

Sign in / Sign up

Export Citation Format

Share Document