Prediction of Flow and Heat Transfer through Stationary and Rotating Ribbed Ducts Using a Non-linear k−ε Model
- 246 Downloads
The present paper deals with the prediction of three-dimensional fluid flow and heat transfer in rib-roughened ducts of square cross-section, which are either stationary, or rotate in orthogonal mode. The main objective is to assess how a recently developed variant of a cubic non-linear k−ε model (proposed by Craft et al. Flow Turbul Combust 63:59–80, 1999) can predict three-dimensional flow and heat transfer characteristics through stationary and rotating ribbed ducts. The present paper discusses turbulent air flow and heat transfer through two different configurations, namely: (I) a stationary square duct with “in-line” normal and (II) a square duct with normal ribs in a “staggered” arrangement under stationary and rotating conditions, with the axis of rotation normal to the flow direction and parallel to the ribs. In this paper the flow and thermal predictions of the linear k−ε model (EVM) are also included, as a set of baseline predictions. The mean flow predictions show that both linear and non-linear k−ε models can successfully reproduce most of the measured data for stream-wise and cross-stream velocity components. Moreover, the non-linear model is able to produce better results for the turbulent stresses. The heat transfer predictions show that both EVM and NLEVM2, the more recent variant of the non-linear k−ε, with the algebraic length-scale correction term, overestimate the measured Nusselt numbers for both geometries examined. While the EVM with the differential length-scale correction term underestimates heat transfer levels, the Nusselt number predictions with the NLEVM2 and the ‘NYP’ term are in close agreements with the measured data. Comparisons with our earlier work, Iacovides and Raisee (Int J Heat Fluid Flow, 20:320–328, 1999), show that the NLEVM2 thermal predictions are of similar quality to those of a second-moment closure.
KeywordsNon-linear k−ε Rib-roughness Rotation Turbulence Heat transfer
Unable to display preview. Download preview PDF.
- 4.Baughn, J.W., Yan, X.: Local heat transfer measurements in square ducts with transverse ribs. In: Proceedings of the 28th National Heat Transfer Conference, vol. 202, pp. 1–7. ASME, San Diego, California (1992)Google Scholar
- 5.Cooper, D.: Computation of momentum and heat transfer in a separated flow using low-reynolds number linear and non-linear k−ε models. MRes Dissertation, Department of Mechanical Engineering, UMIST (1997)Google Scholar
- 6.Craft, T.J., Launder, B.E., Suga, K.: Extending the applicability of eddy viscosity models through the use of deformation invariants and non-linear elements. In: Proceedings of IAHR, 5th International Symposium on Refined Flow Modelling and Turbulence Measurements, pp. 125–132. Paris (1993)Google Scholar
- 15.Iacovides, H., Jackson, D.C., Ji, H., Kelemenis, G., Launder, B.E., Nikas, K.: LDA study of flow development through an orthogonally rotating u-bend of strong curvature and rib-roughened walls. ASME J. Turbomach. 108, 386–391 (1998)Google Scholar
- 18.Iacovides, H., Launder, B.E.: Internal blade cooling: the Cinderella of CFD research in gas turbines. Review paper, Proceedings of the Institution of Mechanical Engineers, Part A. J. Power. Energy. 221, 265–290 (2007)Google Scholar
- 26.Lien, F.S., Leschziner, M.A.: A general non-orthogonal finite-volume algorithm for turbulent flow at all speeds incorporating second-moment turbulence transport closure: Part 1: Numerical implementation, and Part 2: Application. Comput. Methods Appl. Mech. Eng. 14, 123–167 (1994)CrossRefADSMathSciNetGoogle Scholar
- 28.Moon, I.M.: Effects of Coriolis Force on Turbulent Boundary Layers in Rotating Fluid Machines. MIT Gas-Turbine Laboratory, Report No. 74, (1964)Google Scholar
- 31.Raisee, M.: Computation of flow and heat transfer through two- and three-dimensional rib-roughened passages. Ph.D. Thesis, Department of Mechanical Engineering, UMIST (1999)Google Scholar
- 33.Rau, G., Cakan, M., Moeller, D., Arts, T.: The effects of periodic ribs on the aerodynamic and heat transfer performance on a straight cooling channels. ASME J. Turbomach. 120, 368–375 (1998)Google Scholar
- 36.Sewall, E.A., Tafti, D.K.: Large eddy simulation of the developing region of a rotating ribbed internal turbine blade cooling channel. Paper GT2004-53833, ASME Turbo Expo, Vienna, Austria (2004)Google Scholar
- 38.Yap, C.R.: Turbulent heat and momentum transfer in recirculating and impinging flows. Ph.D. Thesis, Faculty of Technology, University of Manchester (1987)Google Scholar