Investigation of Low-Pressure Turbine Endwall Flows: Simulations and Experiments (Postprint)
Abstract
Highly loaded low-pressure turbine (LPT) blades offer opportunities for lower costs and higher performance but suffer from unacceptable endwall losses. This has motivated research aimed at reducing the endwall losses by manipulating the passage vortex that constitutes the primary source of losses. Passive approaches, such as prole and endwall contouring or active flow control, did reduce endwall losses but require a more detailed understanding of the underlying flow physics to be better optimized. Endwall research also suffers from a lack of temporal and spatial resolution of the existing flow data which limits the depth of the physical analysis. LPT endwall flow experiments at the Air Force Research Laboratory revealed the mean flow features but did not resolve the unsteady flow structures. Therefore, the decision was made to carry out endwall simulations with a higher-order-accurate Navier-Stokes code and to investigate the underlying hydrodynamic instabilities. In this paper, results from endwall flow simulation for the L2F geometry with and without endwall fillet are presented. Both a turbulent and a laminar endwall boundary layer are being considered. For the former, a passage vortex is generated at the endwall. The addition of the fillet suppresses the vortex. For the laminar endwall boundary layer, without fillet the passage vortex is missing. This interesting result indicates a strong dependence of the flow topology on the endwall boundary layer properties.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 2015
- Accession Number
- ADA623727
Entities
People
- A. Gross
- R. Sondergaard
Organizations
- Air Force Research Laboratory