Aerodynamic Investigation of the Flow in a Turbine Rear Structure at Realistic Flow Conditions

The development of the current geared engines has increased the demands of its components’ investigation. This article is focused on the last stage of the turbofan engine – turbine rear structure (TRS), a good design of which is crucial for higher efficiency and lower emissions. Studies were performed in an annular rig located at the Chalmers University of Technology, Sweden which represents an engine realistic TRS stage. The static structure of TRS is equipped with 12 outlet guide vanes (OGV) of three different types: regular, thick, and bumped vane. Each type of vane was tested under on- and off-design conditions with swirl angle varying at ±5 degrees from the aerodynamic design point and fixed Reynolds number of 235000. Measurements were done using multi-hole pressure probes and monitoring inlet and outlet planes. Moreover, to visualize the near-wall streamlines and flow separations the oil-film visualization was used. The study shows that the OGVs with increased thickness and with a vane shroud bump are shown to affect the performance of the TRS by influencing the losses on the OGV suction side near the hub. Besides, the implementation of vane equipped with bump leads to a significant influence on the outlet flow from the low-pressure turbine and noticeable downstream influence on the wakes from the OGVs.