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"
}