The effects of air-assist upon liquid fuel jet penetration and dispersion in a cross-flow of preheated air

Z. P. Tan*, E. Lubarsky, O. Bibik, D. Shcherbik, B. T. Zinn

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

Modern gas turbines employ fuel-air mixers that utilize jet-in-cross-flow (JICF) fuel injection to achieve rapid fuel-air mixing. In recent years, air-assist JICF has been investigated to improve the atomization and fuel dispersion qualities provided by JICF. This article reports the results of an experimental investigation where liquid Jet-A was injected into a cross-flow at temperatures and pressures of 316°-427°C and 2.02-2.53 MPa, respectively, while four streams of assist air, supplied from slots in a well, impinged on the fuel jet. The effects of air-assist and fuel-to-cross-flow momentum ratio (J) upon the fuel jet's outer-edge trajectories and wake-region dispersion patterns were investigated using two shadowgraph approaches that used (1) 511 nm visible light at 21 kHz pulse rate and (2) 266/532 nm UV/visible light for multiphase detection. In the experiments, J was varied between 15 and 130, while the air-assist flow rates were varied by changing the percentage pressure drop (dP) between the assist-air supply line and the cross-flow air between 0% and 5%, corresponding to 0%-25% of fuel mass flow rate when J = 15. The measured data were used to develop correlations for the air-assist JICF's outer-edge trajectories, using an effective momentum ratio (Jeff) that accounts for the effects of air-assist. It was observed that while air-assist had minor effects upon the spray's outer-edge trajectories, it significantly affected fuel dispersion within the spray's wake. At higher temperatures and pressures, the outer-edge trajectories were more sensitive to air-assist. Notably, there were no significant differences between the outer-edge trajectories obtained via UV and visible light shadowgraphs, indicating that the outer-edge regions of the spray largely consisted of liquid. In contrast, similar comparisons suggested high concentrations of gaseous fuel in the wake, especially at higher temperatures and pressures.

Original languageEnglish
Pages (from-to)1177-1196
Number of pages20
JournalAtomization and Sprays
Volume26
Issue number11
DOIs
StatePublished - 2016

Keywords

  • Air-assist
  • Correlations
  • Elevated pressure
  • Experimental
  • Fuel-air mixer
  • High-speed
  • Jet-A
  • Jet-in-cross-flow
  • Multiphase
  • Shadowgraph

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