Publication detail

Gas-phase velocity estimation in practical sprays by Phase-Doppler technique

RÁCZ, E. MALÝ, M. JEDELSKÝ, J. JÓZSA, V.

English title

Gas-phase velocity estimation in practical sprays by Phase-Doppler technique

Type

journal article in Web of Science

Language

en

Original abstract

Practical sprays are characterized by a two-way coupling between droplets and the surrounding gas. The effect of sprays on process performance is critical in numerous applications; hence, the gas-phase velocity is often esti-mated via two methods, using Phase Doppler measurement data. The first one is using a rule of thumb, i.e., estimating the gas-phase velocity by analyzing droplet sizes below a few micrometers. The second way of esti-mating the Stokes number, Stk, is using a threshold well below unity, such as 0.1. There are numerous definitions available in the literature for Stk, resulting in several magnitudes difference. These complex problems are resolved in this paper in the following way. A new definition for Stk is provided, which is sufficiently robust for, e.g., pressure and twin-fluid atomizers. According to the results, the Stk < 0.1 threshold means droplet sizes between 2 and 10 micrometers above 10 m/s gas-phase velocities. Filtering for too small droplets could lead to biased characteristics, especially in estimating the turbulent properties. Hence, the gas-phase velocity estimation is a function of the measurement setup and has a significant spatial dependence. The reader can find the software code online and the algorithm in Appendix A.

English abstract

Practical sprays are characterized by a two-way coupling between droplets and the surrounding gas. The effect of sprays on process performance is critical in numerous applications; hence, the gas-phase velocity is often esti-mated via two methods, using Phase Doppler measurement data. The first one is using a rule of thumb, i.e., estimating the gas-phase velocity by analyzing droplet sizes below a few micrometers. The second way of esti-mating the Stokes number, Stk, is using a threshold well below unity, such as 0.1. There are numerous definitions available in the literature for Stk, resulting in several magnitudes difference. These complex problems are resolved in this paper in the following way. A new definition for Stk is provided, which is sufficiently robust for, e.g., pressure and twin-fluid atomizers. According to the results, the Stk < 0.1 threshold means droplet sizes between 2 and 10 micrometers above 10 m/s gas-phase velocities. Filtering for too small droplets could lead to biased characteristics, especially in estimating the turbulent properties. Hence, the gas-phase velocity estimation is a function of the measurement setup and has a significant spatial dependence. The reader can find the software code online and the algorithm in Appendix A.

Keywords in English

atomization; Phase Doppler; velocity; Stokes number; droplet; spray

Released

01.12.2022

Publisher

PERGAMON-ELSEVIER SCIENCE LTD

Location

OXFORD

ISSN

0301-9322

Volume

157

Number

1

Pages from–to

1–14

Pages count

14

BIBTEX


@article{BUT180302,
  author="Erika {Rácz} and Milan {Malý} and Jan {Jedelský} and Viktor {Józsa},
  title="Gas-phase velocity estimation in practical sprays by Phase-Doppler technique",
  year="2022",
  volume="157",
  number="1",
  month="December",
  pages="1--14",
  publisher="PERGAMON-ELSEVIER SCIENCE LTD",
  address="OXFORD",
  issn="0301-9322"
}