Measuring air core characteristics of a pressure-swirl atomizer via a transparent acrylic nozzle at various Reynolds numbers

Eun J. Lee, Sang Youp Oh, Ho Y. Kim, Scott C. James, Sam S. Yoon

Research output: Contribution to journalArticlepeer-review

79 Citations (Scopus)


Because of thermal fluid-property dependence, atomization stability (or flow regime) can change even at fixed operating conditions when subject to temperature change. Particularly at low temperatures, fuel's high viscosity can prevent a pressure-swirl (or simplex) atomizer from sustaining a centrifugal-driven air core within the fuel injector. During disruption of the air core inside an injector, spray characteristics outside the nozzle reflect a highly unstable, nonlinear mode where air core length, Sauter mean diameter (SMD), cone angle, and discharge coefficient variability. To better understand injector performance, these characteristics of the pressure-swirl atomizer were experimentally investigated and data were correlated to Reynolds numbers (Re). Using a transparent acrylic nozzle, the air core length, SMD, cone angle, and discharge coefficient are observed as a function of Re. The critical Reynolds numbers that distinguish the transition from unstable mode to transitional mode and eventually to a stable mode are reported. The working fluids are diesel and a kerosene-based fuel, referred to as bunker-A.

Original languageEnglish
Pages (from-to)1475-1483
Number of pages9
JournalExperimental Thermal and Fluid Science
Issue number8
Publication statusPublished - 2010 Nov

Bibliographical note

Funding Information:
This research was supported by a grant from Development of Engine System for HEV Project, funded by the Ministry of Knowledge Economy. The last author acknowledges that this study was partially supported by a grant from the cooperative R&D Program (B551179-08-03-00) funded by the Korea Research Council Industrial Science and Technology and also by KETEP (2009-3021010030-11-1).


  • Air core
  • Fuel injector performance
  • Swirl spray
  • Temperature effect

ASJC Scopus subject areas

  • General Chemical Engineering
  • Nuclear Energy and Engineering
  • Aerospace Engineering
  • Mechanical Engineering
  • Fluid Flow and Transfer Processes


Dive into the research topics of 'Measuring air core characteristics of a pressure-swirl atomizer via a transparent acrylic nozzle at various Reynolds numbers'. Together they form a unique fingerprint.

Cite this