Publication detail

Internal flow and air core dynamics in Simplex and Spill-return pressure-swirl atomizers

MALÝ, M. JANÁČKOVÁ, L. JEDELSKÝ, J. SLÁMA, J. SAPÍK, M. WIGLEY, G.

Original Title

Internal flow and air core dynamics in Simplex and Spill-return pressure-swirl atomizers

Type

book chapter

Language

English

Original Abstract

It is well known that the spray characteristics of pressure-swirl atomizers are strongly linked to the internal flow and that an unstable air core may cause instabilities in the spray. In this paper, a 10:1 scale transparent Plexiglas (PMMA) model of a pressure-swirl atomizer as used in a small gas turbine is introduced. The internal flow was examined using high-speed imaging, laser-Doppler anemometry and computational fluid dynamics tools. The experimental and numerical results were analysed and compared in terms of the air core morphology and its temporal stability. Two different liquids were used, Kerosene-type Jet A-1 represented a commonly used fuel while p-Cymene (4-Isopropyltoluene) matched the refractive index of the Plexiglas atomizer body. The internal flow characteristics were set using dimensionless numbers i.e. the Reynolds number and Froude number. The flow test conditions were limited to inlet Reynolds numbers from 750 to 1750. Two atomizers were examined to represent a Simplex and Spill-return (SR) geometries. In a comparative manner, the SR atomizer features a central passage in the rear wall of the swirl chamber. The main advantage of this concept is that the fuel is always supplied to the swirl chamber at a high pressure therefore providing good atomization over a wide range of the injection flow rate. However, the presence of the spill orifice strongly affects the internal flow even if the spill-line is closed. The air core in the Simplex atomizer was found fully developed and stable. The SR atomizer behaved differently, the air core did not form at all, and the spray was therefore unstable.

Keywords

Internal flow dynamics, Pressure-swirl, transparent nozzle, CFD

Authors

MALÝ, M.; JANÁČKOVÁ, L.; JEDELSKÝ, J.; SLÁMA, J.; SAPÍK, M.; WIGLEY, G.

Released

8. 9. 2017

Location

Valencie

ISBN

978-84-9048-580-4

Book

28TH CONFERENCE ON LIQUID ATOMIZATION AND SPRAY SYSTEMS, ILASS-EUROPE 2017

Pages from

233

Pages to

240

Pages count

8

URL

http://dx.doi.org/10.4995/ILASS2017.2017.4995

BibTex

@inbook{BUT140660,
  author="Milan {Malý} and Lada {Janáčková} and Jan {Jedelský} and Jaroslav {Sláma} and Marcel {Sapík} and Graham {Wigley}",
  title="Internal flow and air core dynamics in Simplex and Spill-return pressure-swirl atomizers",
  booktitle="28TH CONFERENCE ON LIQUID ATOMIZATION AND SPRAY SYSTEMS, ILASS-EUROPE 2017",
  year="2017",
  address="Valencie",
  pages="233--240",
  doi="10.4995/ILASS2017.2017.4995",
  isbn="978-84-9048-580-4",
  url="http://dx.doi.org/10.4995/ILASS2017.2017.4995"
}