Effects of Different Turbulence Models in Simulation of Unsteady Tip Leakage Flow in Axial Compressor Rotor Blades Row
Authors
Abstract:
Characteristics of rotor blade tip clearance flow in axial compressors can significantly affect their performance and stable operation. It may also increase blade vibrations and cause detrimental noises. Therefore, this paper is contributed to investigate tip leakage flow in a low speed isolated axial compressor rotor blades row. Simulations are carried out on near-stall condition, which is valuable of being studied in detail. In turbomachines, flows are non-isotropic and highly three-dimensional. The reason arises from the complicated structure of bounded walls, tip leakage flows, secondary flows, swirl effects, streamlines curvatures and pressure gradients along different directions. As a result, accurate studies on tip leakage flow would be accompanied by many challenges such as adopting suitable turbulence models. So, investigations are carried out numerically utilizing two well-known turbulence models of k-ε and k-ω-SST, separately. It is shown that the k-ε model yields poor results in comparison to the k-ω-SST model. To realize reasons for this discrepancy, turbulence parameters such as turbulent kinetic energy, dissipation and eddy viscosity terms at the tip clearance region were surveyed in detail. It is found out that estimation for eddy viscosity term is too high in the k-ε model due to excessive growth of turbulent kinetic energy, time scale, and lack of effective damping coefficient. This leads to dissipation of vortical structure of flow and wrong estimation of flow field at the rotor tip clearance region. Nevertheless, k-ω-SST turbulence model provides results consistent with reality.
similar resources
Aspects of Two-Phase Flow Screw Compressor Modelling Part I: Leakage Flow and Rotor Tip Friction
A one-dimensional leakage flow model for two-phase ammonia-water twin screw compressors is presented. The model takes into account viscous and acceleration forces and is based on three conservation equations and on the equation of state for homogenous NHiH20 mixture. The governing equations are solved with a finite difference method. Numerical shooting is used to find such inlet flow velocity a...
full texteffect of sub-grid scales on large eddy simulation of particle deposition in a turbulent channel flow
چکیده ندارد.
15 صفحه اولthe effects of changing roughness on the flow structure in the bends
flow in natural river bends is a complex and turbulent phenomenon which affects the scour and sedimentations and causes an irregular bed topography on the bed. for the reason, the flow hydralics and the parameters which affect the flow to be studied and understand. in this study the effect of bed and wall roughness using the software fluent discussed in a sharp 90-degree flume bend with 40.3cm ...
Unsteady Transonic Flows in an Axial Flow Compressor*
Introduction. This paper deals with some transonic flow problems for the supersonic axial flow compressor: these arise in connection with flutter analysis for fan blading. Very detailed solutions for unsteady plane transonic flows through a cascade of flat plates have been given by Goldstein Braun and Adamczyk (1977) and Nagashima and Whitehead (1977), see also Goldstein (1975), Kurosaka (1974)...
full textNumerical Simulation of Unsteady Flow in a Scroll Compressor
A new template simulation tool is developed for scroll compressors/expanders. This scroll template generates a high quality multi-block structured mesh from the outlines of stationary and orbiting rotors, which are inputs from a user. The mesh movement is also automatically calculated to account for every position of the orbiting rotor, maintaining good grid quality and smooth movement througho...
full textMy Resources
Journal title
volume 8 issue 1
pages 61- 74
publication date 2018-09-01
By following a journal you will be notified via email when a new issue of this journal is published.
Hosted on Doprax cloud platform doprax.com
copyright © 2015-2023