Laminarization of internal flows under the combined effect of strong curvature and rotation

GÜLEREN K. M., Afgan I., Turan A.

JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME, cilt.130, sa.9, 2008 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 130 Sayı: 9
  • Basım Tarihi: 2008
  • Doi Numarası: 10.1115/1.2953298
  • Dergi Adı: JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Anahtar Kelimeler: centrifugal compressor, curvature, laminarization, LES, rotation, U-duct, DIRECT NUMERICAL-SIMULATION, LARGE-EDDY SIMULATIONS, NUMBER TURBULENT-FLOW, HEAT-TRANSFER, GAS-FLOWS, SQUARE, STATIONARY, VALIDATION, PREDICTION, VISCOSITY
  • Eskişehir Osmangazi Üniversitesi Adresli: Evet

Özet

The laminarization phenomenon for the flow under the combined effect of strong curvature and rotation is discussed based on numerical predictions of large-eddy simulation (LES). Initially, the laminarization process is presented for the fully developed flow inside a spanwise rotating straight square duct. LES predictions over a wide range of rotation numbers (Ro=0-5) show that the turbulent kinetic energy decreases monotonically apart from 0.2 < Ro < 0.5. Subsequently, a spanwise rotating U-duct flow is considered with Ro=+/- 0.2. The interaction of curvature and Coriolis induced secondary flows enhances the turbulence for the negative rotating case, whereas this interaction ensues strong laminarization for the positive rotating case. Finally, the laminarization is presented in the impeller of a typical centrifugal compressor, rotating at a speed of Omega=1862 rpm (Ro=0.6). The resulting LES predictions are observed to be better than those of Reynolds-averaged Navier-Stokes (RANS) in the regions where turbulence is significant. However, for the regions dominated by strong laminarization, RANS results are seen to approach those of LES and experiments.