Investigation of Flow Structures and Losses at the Endwall Sections of the Last Stage Blade
The paper presents the detailed investigation of the flow structure and losses in a hub and tip sections of the last blade of the multistage turbine. The design of the last blade has been carried out on the basis of the in-house blade generator (BLAGEN) which allows to create optimal plane sections (usually 3–5) along blade height and to stack whole blades of various 3D shapes. The viscous flow structure and the loss variation have been investigated at the endwall sections of the last blade by means of 2D and 3D Navier–Stokes codes. These investigations have been carried out for a wide range of modes and incidences. As a result the influence of the following parameters (maximum thickness-to-chord ratio, leading metal angle, Re number, exit Ma number and etc.) on the flow structure and losses has been investigated. On the basis of these investigations some recommendations for the last blades design have been developed. Numerical investigations have been validated by the comparison between numerical and test data for the outlet flow.