Detail publikace

Dynamika kapek ve spreji dvoumédiových trysek s vnitřním směšováním

JEDELSKÝ, J. JÍCHA, M.

Originální název

Droplet dynamics in internally mixed twin-fluid spray

Český název

Dynamika kapek ve spreji dvoumédiových trysek s vnitřním směšováním

Anglický název

Droplet dynamics in internally mixed twin-fluid spray

Typ

abstrakt

Jazyk

en

Originální abstrakt

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 10 and very weakly interact with the gas.

Český abstrakt

Článek popisuje dynamiku kapek ve spreji dvoumédiových trysek s vnitřním směšováním, více v anglické verzi: 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 10 and very weakly interact with the gas.

Anglický abstrakt

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 10 and very weakly interact with the gas.

Klíčová slova

effervescent atomizace, dispersní dvoufázový tok, dynamika kapek, sprej, dvoumédiové trysky s vnitřním směšováním

Vydáno

03.06.2013

Nakladatel

WIT Press

Místo

La Coruňa, Spain

Strany od

1

Strany do

12

Strany počet

12

BibTex


@misc{BUT104324,
  author="Jan {Jedelský} and Miroslav {Jícha}",
  title="Droplet dynamics in internally mixed twin-fluid spray",
  annote="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  10 and very weakly interact with the gas.",
  address="WIT Press",
  booktitle="Sixteenth International Conference on Computational Methods and Experimental Measurements XVI",
  chapter="104324",
  institution="WIT Press",
  year="2013",
  month="june",
  pages="1--12",
  publisher="WIT Press",
  type="abstract"
}