Scaling of Effervescent Atomization and Industrial Two-phase Flow PDF Download
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Author: Mohammad Azizur Rahman
Publisher:
ISBN:
Category : Atomization
Languages : en
Pages :
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Book Description
Author: Mohammad Azizur Rahman
Publisher:
ISBN:
Category : Atomization
Languages : en
Pages :
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Book Description
Author: Jinghai Li
Publisher:
ISBN:
Category : Fluid dynamics
Languages : en
Pages : 224
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Book Description
Author: Sanaz Arabzadeh Esfarjani
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Liquid atomization is widely used in industrial applications such as aerospace, combustion, pharmaceutical, spray coatings, and surface engineering. The main concern of atomization is to have a controllable and uniform spray. In suspension plasma spraying technique, where the attempt is to reach nano-scaled uniform coatings, there is a vital demand to produce a uniform and non-pulsating spray. Effervescent atomizers, in which a gas is bubbled into the bulk liquid through an aerator, have shown to be a technological alternative to the conventional atomizers when atomization of liquids with large variety of viscosity and density is required. Thus, understanding the behavior of gas and liquid flow through the nozzle is crucial to predict the condition of outcoming spray. The objective of this study is to numerically investigate the two-phase flow inside the effervescent atomizers. Using the incompressible Eulerian/Eulerian approach, the three-dimensional structure of two-phase flow inside an aerated-liquid injector is modeled. The behavior of liquid film in the discharge passage is investigated using different Gas to Liquid mass flow Ratios (GLR). These numerical results are compared with the experimental data available in literature. The effect of nano-sized solid particles concentration on the liquid film thickness at the exit of the atomizer is studied through the change in liquid bulk density and viscosity.
Author: Mona Hassanzadeh Jobehdar
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
Effervescent atomization uses the internal gas-liquid mixture to produce spray. The behavior of two-phase flow inside the atomizer influences the spray characteristics and is dependent on the atomizer internal geometry and operating conditions. The present study is conducted in two parts; study of the bubble formation from a novel submerged nozzle in a liquid cross-flow and investigation of the internal and external two-phase flows in an effervescent atomizer. The present study investigated the performance of a novel nozzle developed by Gadallah and Siddiqui (2013) in the liquid cross-flow. The impact of the nozzle shape, its configurations and orientations was experimentally investigated. The results showed that the novel nozzle generates smaller bubbles at higher detachment frequency for all cases compared to the standard nozzle. It is found that the elastic rebound of the bubble from a side hole plays a key role in the early bubble detachment. For the effervescent atomizer study, the impact of atomizer's internal geometry on the internal flow and spray droplet characteristics were studied. The results demonstrated that a conical base aerator tube and shorter mixing zone length provide more uniform bubbles in smaller size. A new type of bubble breaker was designed and tested in an effervescent atomizer. The results show that both internal and external two-phase flows in the atomizer were strongly influenced by bubble breaker configurations (diameter and number of holes). It was found that the liquid shear stress is the dominant force causing the bubble elongation and its eventual breakup.
Author: Mohammad Rahman
Publisher: LAP Lambert Academic Publishing
ISBN: 9783846520604
Category :
Languages : en
Pages : 264
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Book Description
Scaling laws for effervescent atomization has been established successfully. A power law correlation for bubble and droplet size has been established. Effects of gas property on effervescent atomization have been studied. A coupled Phase Doppler Particle Anemometer and Impulse Probe technique has been proposed to measure the mass flux in the multiphase dense spray. Global droplet size has been studied in contrast to the point/peripheral/centerline spray profile measurements.
Author:
Publisher:
ISBN:
Category : Atomization
Languages : en
Pages : 530
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Book Description
Author: G. Kocamustafaogullari
Publisher:
ISBN:
Category : Scaling laws (Nuclear physics)
Languages : en
Pages : 38
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Book Description
Author:
Publisher:
ISBN:
Category : Atomization
Languages : en
Pages : 470
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Book Description
Author: Seyed Milad Mousavi
Publisher:
ISBN:
Category :
Languages : en
Pages : 92
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Book Description
Atomization is a process where the bulk of liquid jet disintegrates into liquid sheets, ligaments and droplets. It has enormous applications in industries and processes such as combustion, heat transfer systems, transport, biological systems and particularly our interest, coating processes. The Effervescent nozzle is a type of twin-fluid atomizer and has shown a superior performance in handling and spraying different liquids without any clogging issues; which is particularly interesting in thermal spray. In spite of significant number of experimental works, a few numerical works have been carried out. That makes it crucial to conduct a comprehensive numerical study on Effervescent atomizer. The complex internal and external behaviors of Effervescent atomizer are governing the behavior of the flow. The latter is a turbulent and compressible multiphase flow. It is studied numerically by employing a three-dimensional compressible Eulerian method along with Volume of Fluid (VOF) surface-tracking method coupled with the Large Eddy Simulation (LES) turbulence model. The numerical study is conducted by using OpenFoam library, an open-source package introduced by Open-CFD. In this study, the effect of varying the gas to liquid ratio (GLR) and the suspension (i.e. effect of viscosity, density and surface tension), on the structure of internal flow and consequently, the external flow is studied numerically. It is observed that the increase in GLR is accompanied with an evolution of the internal flow from a complex bubbly flow to an annular flow. This reduces the liquid film thickness at the discharge orifice. Further studies on internal pressure illustrated the critical condition, choked flow and pressure oscillations at the discharge orifice. The examination of increasing the GLR and evolving of internal flow resulted in changing in primary atomization parameters such as shortening the breakup length and widening the spray cone angle. Furthermore, the existence of a slip velocity between the two phases in the external flow results in dominant aerodynamic forces at high GLRs. Moreover, alternation of the liquid properties illustrated the higher spray velocity and wider cone angle of the spray, which demonstrates the superior performance of the Effervescent atomizer.
Author: David Azbel
Publisher: Cambridge University Press
ISBN: 9780521237727
Category : Science
Languages : en
Pages : 372
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Book Description
The behaviour of bubbles is a unifying theme of this book. From an explanation of the fundamentals of bubbles formation at a single orifice, Dr Azbel goes on to set up equations for bubble motion, bubble size, bubble-size distribution and pressure drop across a perforated plate.
