Three-dimensional flow structures and droplet-gas mixing process of a liquid jet in supersonic crossflow

Research output: Contribution to journalArticle

Abstract

The mixing process of a liquid jet in supersonic crossflow with a Mach number of 2.1 was investigated numerically using large eddy simulation (LES) based on the Eulerian-Lagrangian method. The gas phase was described using the Navier-Stokes equations and the liquid phase was represented using discrete droplets, which were injected and tracked in the computational domain individually according to Newton's second law of motion. The KH (Kelvin-Helmholtz) breakup model was used to calculate the droplet stripping process, and the secondary breakup process was simulated by coupling the RT (Rayleigh-Taylor) breakup model and the TAB (Taylor Analogy Breakup) model. Two-way coupling was enforced to consider the momentum and energy exchange between the gas and the droplets. It was found that the LES predicted spray characteristics, including spray penetration and cross-sectional distribution, agree reasonably well with the experiment. The major gas flow structures such as the bow shock, the large-scale vortices, and the recirculation zones were replicated successfully in the simulations. It was found that the gas flow structures have a significant effect on the mixing process of the droplets. The simulation results revealed that two sets of counter-rotating vortex pair (CVP) exist in the gas-liquid mixing region. Under the influence of CVP, part droplets were transported to the near wall region and subsequently to both sides of the core spray region. The formation mechanism of the CVP was analyzed by comparing the pressure gradient and the source term of droplets in the Navier-Stokes equations. Differences of the mixing process of liquid jet in supersonic crossflow, gas jet in supersonic crossflow and liquid jet in incompressible crossflow were identified.

Details

Authors
  • Peibo Li
  • Zhenguo Wang
  • Xue Song Bai
  • Hongbo Wang
  • Mingbo Sun
  • Liyin Wu
  • Chaoyang Liu
Organisations
External organisations
  • National University of Defense Technology
  • China Aerodynamics Research and Development Center
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Fluid Mechanics and Acoustics

Keywords

  • Counter-rotating vortex pair (CVP), Eulerian-Lagrangian, Large-eddy simulation, Liquid jet, Mixing process, Supersonic crossflow
Original languageEnglish
Pages (from-to)140-156
Number of pages17
JournalAerospace Science and Technology
Volume90
Publication statusPublished - 2019
Publication categoryResearch
Peer-reviewedYes