INVESTIGATION OF THE EFFECT OF THE WAKE GENERATED BY ROTOR BLADES ON THE FLOW THROUGH STATOR PASSAGE FOR LOW PRESSURE TURBINE
Main Article Content
Abstract
The effects of incoming wakes of upstream rotor on the flow field in a low pressure turbine cascade are investigated. The flow field is studied numerically with and without inlet wake. The rotor effect is represented by moving bars that produce passing wakes at the entrance of the stator. The flow field is analyzed numerically by solving the steady and unsteady forms of the two-dimensional compressible Reynolds-averaged Navier-Stokes equations. Steady flow is performed without wake while the unsteady flow is performed with periodic inlet wake for Reynolds number of order 105. A k- turbulence model is used to obtain the eddy viscosity. The Cartesian velocity components and pressure on a collocated (non-staggered) grid are used as dependent variables in the momentum equations, which discretized by finite volume method, body fitted coordinates are used to represent the complex blade geometry accurately, and grid generation technique based on elliptic partial differential equations is employed. SIMPLE algorithm is used to adjust the velocity field to satisfy the conservation of mass. The results show that the wake passing produces unsteady pressure field in the direction of the rotor traverse. The comparison with the experimental data is acceptable and there is similar trend between the prediction and experimental data, except at the separation flow region due to the limitation of the turbulence model.
Article Details
How to Cite
Publication Dates
References
Ahmed, W. M., 2005, "Investigation of the Effect of the Wake Generated by Rotor Blades on the Flow in Stator Passage for Low Pressure Turbine", Ph.D. Thesis, University of Baghdad , Mechanical Engineering Department.
Denton, D. J., 1983, "An Improved Time-Marching Method for Turbomachinery Flow Calculation", ASME Journal of Engineering for Power, Vol.105, PP 514-520.
Giles, M. B., 1987, "Calculation of Unsteady Wake/Rotor Interactions", AIAA Paper No. 87-0006.
Hodson, H. P., 1985, "An Inviscid Blade-to-Blade Prediction of A Wake Generated Unsteady Flow", ASME Journal for Gas Turbines and Power, Vol.107, PP 337-344.
Hodson, H. P., and Dawes, W. N., 1998, "On the Interpretation of Measured Profile Losses in Unsteady Wake-Turbine Blade Interaction Studies", ASME Journal of Turbomachinery, Vol.120, April, 276-284.
Launder, B. E., and Spalding, D.B., 1974," The Numerical Computational of Turbulent Flow", Computer Methods in Applied Mechanics and Engineering, Vol.3, PP 269-289.
Meyer, R. X., 1958, "The Effects of Wakes on the Transient Pressure and Velocity Distributions in Turbomachines", ASME Journal of Basic Engineering, October, PP 1544-1552.
Parker, R., and Watson, J. F., 1972, "Interaction Effects Between Blade Rows in Turbomachines", Proc. of I. Mech. E., 168, No.21.
Reda R. M., 1989, "A Study of Unsteady Rotor-Stator Interactions" ASME Journal of Turbomachinery, Vol.111, October, PP 394-400.
Stieger, R. D., 2002,"The Effects of Wakes on Separating Boundary Layers in Low Pressure Turbine", Ph.D. Thesis, Cambridge University Engineering Department.