RANS MODELING OF FLOW IN ROTATING CAVITY SYSTEM

The accurate prediction of fluid flow within rotating systems has a primary role for the reliability and performance of gas turbine engine. The selection of a suitable turbulence model for the study of such complex flows remains an open issue in the liter- ature. This paper reports a numerical benchmark of the most used eddy viscosity RANS models available within the commercial CFD solvers Fluent and CFX together with an innovative Reynolds Stress Model closure. The predictions are compared to experimen- tal data and previous numerical calculations available in the open literature for three test cases. Test case 1 corresponds to a rotating cavity with a radial outflow, considered ex- perimentally by Owen and Pincombe (19). In that case, the main difficulty arises from the choice of the boundary conditions at the outlet. Several types of boundary conditions have been then considered. All models fail to predict the radial velocity distribution. Nev- ertheless, the RSM offers the best agreement against the experimental data in terms of the averaged tangential velocity in the core. Test case 2 corresponds to a Taylor-Couette system with an axial Poiseuille flow studied experimentally by Escudier and Gouldson (6). Even if the two-equation models provide reliable data for the mean velocity field, they strongly underestimate the turbulence intensities everywhere. The agreement between the RSM and the measurements is rather satisfactory for the mean and turbulent fields, though this second-order closure does not predict the asymmetry of the normal stresses. The main discrepancies appear indeed very close to the stator. Test case 3 is a rotor-stator system with throughflow, corresponding to the test rig of Poncet et al. (22, 23). All the models catch the main features of rotor-stator flows, such as the value of the entrainment coeffi- cient or the location of the transition from the Stewartson to the Batchelor flow structures. The RSM improves especially the predictions of the shear stress.

[1]  K. Stewartson.  On the flow between two rotating coaxial disks , 1953, Mathematical Proceedings of the Cambridge Philosophical Society.

[2]  J. M. Owen,et al.  Velocity measurements inside a rotating cylindrical cavity with a radial outflow of fluid , 1980, Journal of Fluid Mechanics.

[3]  Paul A. Durbin,et al.  RANS simulations of rotating flows , 1999 .

[4]  John W. Chew.  Computation of flow and heat transfer in rotating-disc systems , 1987 .

[5]  H. Aoki,et al.  Convective Heat Transfer in an Annulus with an Inner Rotating Cylinder , 1966 .

[6]  Patrick Bontoux,et al.  Spatio—temporal behaviour in a rotating annulus with a source—sink flow , 1996, Journal of Fluid Mechanics.

[7]  Brian Launder,et al.  Application of a new second-moment closure to turbulent channel flow rotating in orthogonal mode , 1994 .

[8]  M. P. Escudier,et al.  Concentric annular flow with centerbody rotation of a Newtonian and a shear-thinning liquid , 1995 .

[9]  Guillaume Dufour,et al.  Two-equation modeling of turbulent rotating flows , 2005 .

[10]  J. M. Owen,et al.  Source–sink flow inside a rotating cylindrical cavity , 1985, Journal of Fluid Mechanics.

[11]  Sébastien Poncet.  Écoulements de type rotor-stator soumis à un flux axial : de Batchelor à Stewartson , 2005 .

[12]  Nam-Sub Woo,et al.  Flow of Newtonian and Non-Newtonian Fluids in a Concentric Annulus With Rotation of the Inner Cylinder , 2003 .

[13]  Christopher A. Long,et al.  The Effect of Inlet Conditions on Heat Transfer in a Rotating Cavity With a Radial Outflow of Fluid , 1986 .

[14]  Hector Iacovides,et al.  Turbulence modeling of axisymmetric flow inside rotating cavities , 1991 .

[15]  T. Gatski,et al.  On explicit algebraic stress models for complex turbulent flows , 1992, Journal of Fluid Mechanics.

[16]  Sébastien Poncet,et al.  Centrifugal Flow in a Rotor-Stator Cavity , 2005 .

[17]  Heinz-Otto Kreiss,et al.  On the swirling flow between rotating coaxial disks: Existence and nonuniqueness , 1982 .

[18]  Antti Hellsten,et al.  Some improvements in Menter's k-omega SST turbulence model , 1998 .

[19]  Hyung Jin Sung,et al.  Large-eddy simulation of turbulent flow in a concentric annulus with rotation of an inner cylinder , 2005 .

[20]  S. V. Patankar,et al.  Flow Prediction in Rotating Ducts Using Coriolis-Modified Turbulence Models , 1980 .

[21]  R. Schiestel,et al.  Modeling of anisotropic turbulence in rapid rotation , 1997 .

[22]  F. Menter.  Two-equation eddy-viscosity turbulence models for engineering applications , 1994 .

[23]  Laurent Elena,et al.  Turbulence modeling of rotating confined flows , 1996 .

[24]  A. Faller,et al.  An experimental study of the instability of the laminar Ekman boundary layer , 1963, Journal of Fluid Mechanics.

[25]  Sébastien Poncet,et al.  Batchelor versus Stewartson flow structures in a rotor-stator cavity with throughflow , 2005 .