Journal of Applied Mechanical Engineering

Influence of laminar-to-turbulent transition on 3D flow in turbine subsonic cascade

4^th International Conference and Exhibition on Mechanical & Aerospace Engineering

October 03-04, 2016 Orlando, USA

Sergiy Yershov

National Academy of Sciences of Ukraine, Ukraine

Posters & Accepted Abstracts: J Appl Mech Eng

Abstract:

This study presents a numerical simulation of a 3D viscous flow in a subsonic turbine cascade taking into account the laminar-toturbulent transition. The numerical simulation is performed using the RANS equations and the k-�? SST turbulence model. The Langtry�??s PTM model is used for transition modeling. Computations of both fully turbulent and transitional flows are carried out. Much attention is given to the comparison between the present numerical results and the existing experimental data, which was based on the surface distributions of velocity, friction velocity, flow acceleration coefficient, the displacement thickness and shape-factor, the momentum thickness Reynolds number, and velocity profiles upstream and downstream the transition point. Most of the compared data demonstrates good agreement. Our numerical results show the influence of the transition on the secondary flow pattern. When compared with the fully turbulence flow case, the endwall boundary layer cross-flow starts upstream, and it is more intensive, but less massive due to thinner boundary layer in the laminar flow region in the case of transitional flow. Because of these effects, the near-endwall discrete vortex in the wake is more intensive, but the total cascade energy losses are smaller. This mixed influence of the transition on the energy losses in various regions of the 3D flow gives an opportunity for improving cascade efficiency by controlling the transition point location. We can conclude that the proposed approach reflects main features of such flows and allows studying an influence of the laminar-to turbulent transition on the 3D cascade flow structure.

Biography :

Email: sergiy.v.yershov@gmail.com