Droplet dynamics in internally mixed twin-fluid spray

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216305%3A26210%2F14%3APU111733" target="_blank" >RIV/00216305:26210/14:PU111733 - isvavai.cz</a>

Výsledek na webu

<a href="http://www.witpress.com/elibrary/wit-transactions-on-engineering-sciences/82/27290" target="_blank" >http://www.witpress.com/elibrary/wit-transactions-on-engineering-sciences/82/27290</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.2495/AFM140201" target="_blank" >10.2495/AFM140201</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Droplet dynamics in internally mixed twin-fluid spray

Popis výsledku v původním jazyce

Effervescent atomizers are based on mixing of gas with liquid prior to discharge. We describe the discharge of two-phase mixture and movement of droplets in gas jet using simple theoretical models, following with elucidation of droplets dynamics using experimental data for an effervescent spray. Discharge of the liquid-gas flow from the nozzle is described using a combination of two discharge models. Depending on operation conditions, 59–64% of the total discharged mass corresponds to Separated Flow Model and the rest to Homogeneous Flow Model. Discharge velocity of the liquid reaches 12–27% of the gas exit velocity. The liquid-gas velocity ratio is negatively correlated with gas-to-liquid mass ratio (GLR) and positively correlated with inlet pressure. Radial profiles of axial droplet velocity, as measured using Phase Doppler anemometry, are axisymmetric bell-shaped with a maximum in the centreline analogous to the profile defined for a simple gas jet which however is more flat near the centreline and decline much faster for higher radial positions. Mean velocity in particular spray position varies with particle size within a range of several m/s typically. This variation is closely related with particle Stokes number, Stk. Variation of mean velocity with operation pressure and GLR can be explained with discharge conditions; higher pressures and GLRs lead to higher discharge velocities that are reflected in the spray downstream. Stokes numbers are generally << 1 for particle sizes Dp up to 10 um so they smoothly follow the gas flow. Stk for size 10 um <Dp< 50 um depends on flow regime and position in the spray and can be found typically within a range 0.1 < Stk < 10. Particles with Dp larger than 100 um have usually Stk > 10 and very weakly interact with the gas.

Název v anglickém jazyce

Droplet dynamics in internally mixed twin-fluid spray

Popis výsledku anglicky

Effervescent atomizers are based on mixing of gas with liquid prior to discharge. We describe the discharge of two-phase mixture and movement of droplets in gas jet using simple theoretical models, following with elucidation of droplets dynamics using experimental data for an effervescent spray. Discharge of the liquid-gas flow from the nozzle is described using a combination of two discharge models. Depending on operation conditions, 59–64% of the total discharged mass corresponds to Separated Flow Model and the rest to Homogeneous Flow Model. Discharge velocity of the liquid reaches 12–27% of the gas exit velocity. The liquid-gas velocity ratio is negatively correlated with gas-to-liquid mass ratio (GLR) and positively correlated with inlet pressure. Radial profiles of axial droplet velocity, as measured using Phase Doppler anemometry, are axisymmetric bell-shaped with a maximum in the centreline analogous to the profile defined for a simple gas jet which however is more flat near the centreline and decline much faster for higher radial positions. Mean velocity in particular spray position varies with particle size within a range of several m/s typically. This variation is closely related with particle Stokes number, Stk. Variation of mean velocity with operation pressure and GLR can be explained with discharge conditions; higher pressures and GLRs lead to higher discharge velocities that are reflected in the spray downstream. Stokes numbers are generally << 1 for particle sizes Dp up to 10 um so they smoothly follow the gas flow. Stk for size 10 um <Dp< 50 um depends on flow regime and position in the spray and can be found typically within a range 0.1 < Stk < 10. Particles with Dp larger than 100 um have usually Stk > 10 and very weakly interact with the gas.

Druh

D - Stať ve sborníku

CEP obor

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OECD FORD obor

10305 - Fluids and plasma physics (including surface physics)

Projekt

<a href="/cs/project/GAP101%2F11%2F1264" target="_blank" >GAP101/11/1264: Vlastnosti spreje nízkotlakých dvoumédiových trysek s vnitřním směšováním provozovaných s kapalinami o velkém rozsahu viskozity</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2014

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název statě ve sborníku

Advances in Fluid Mechanics X

ISBN

978-1-84564-791-9

ISSN

1743-3533

e-ISSN

—

Počet stran výsledku

12

Strana od-do

227-238

Název nakladatele

WIT Press

Místo vydání

A Coruňa, Spain

Místo konání akce

A Coruña

Datum konání akce

1. 7. 2014

Typ akce podle státní příslušnosti

WRD - Celosvětová akce

Kód UT WoS článku

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