On the highly swirling flow through a confined bluff-body

Alisson Vinicius Brito Lopes, Nwabueze Emekwuru, Bernard Bonello, Ebrahim Abtahizadeh

Research output: Contribution to journalArticle

Abstract

We address highly swirling, confined-bluff-body-flow evolving through a burner; particularly, contributions of the swirling motion to a central-recirculation-zone (CRZ) downstream the injector. Previous studies suggest that flame stability reduces in combustors lacking this zone; careful consideration of the CRZ is thus desirable. We use Reynolds-Averaged-Navier–Stokes (RANS) and Large-Eddy-Simulation (LES) to simulate the flow, and the influence of the swirl device was included in defining the inflow conditions for LES simulations. We use mean velocity profiles and turbulence statistics to test results. There is qualitative agreement between computed and reported experimental data, and we document quantitative differences obtained with the RANS models. LES velocity field results are mostly within 3% of the experimental data, better than the latest reported LES data, reinforcing the suitability of our approach. We took advantage of the quality of the LES mesh, which solves 95.6% of the resolved-turbulence-energy, to present the vorticity structures showing the precessing vortex motion on the CRZ boundaries. Anisotropic states of the Reynolds-stress were characterized with the aid of an anisotropy invariant map, a novelty for this type of burner; the turbulence states considerably vary inside the burner, behaving isotropically in the center of the CRZ, whereas axisymmetric turbulence is predominant in the other areas of the CRZ. The results reinforce the importance of applying appropriate turbulence models and inflow conditions for simulations involving confined-bluff-body-flows in order to capture the main flow fields and structures in the CRZ.
Original languageEnglish
Article number055105
Number of pages25
JournalPhysics of Fluids
Volume32
Early online date11 May 2020
DOIs
Publication statusPublished - 11 May 2020

Funder

UGC-UKIERI (Grant No. 2016-17-050).

Keywords

  • Swirl flow
  • LES

ASJC Scopus subject areas

  • Modelling and Simulation
  • Aerospace Engineering
  • Mechanical Engineering
  • Energy Engineering and Power Technology

Fingerprint Dive into the research topics of 'On the highly swirling flow through a confined bluff-body'. Together they form a unique fingerprint.

  • Cite this