Experimental Investigation of Turbulence Inside an Annular Turbine Exit Guide Vane Cascade With Unsteady Wakes and Purged Cavity Using Constant Temperature Anemometry

Abstract

Abstract. The total efficiency of jet engines can be increased by implementing recuperative systems. These systems need an increased fluid total temperature downstream of the low-pressure turbine (LPT). Thus, a method is needed to prevent hot gas from entering the slot cavity between the LPT's last rotor row and the stationary turbine rear frame (TRF). As a result, cold air gets extracted from the low-pressure compressor and purged into the slot cavity, which eventually enters the main gas path at the hub upstream of the TRF's turbine exit guide vanes. The present work yields results on the turbulent characteristics of the flow field downstream of an annular turbine exit guide vane cascade under the influence of unsteady wakes migrating through the domain. For this purpose, a rotating spoke wheel is located upstream of the test item. In addition, purge air is ingested into the main gas path through the slot cavity formed between the rotating spoke wheel and the stationary turbine exit guide vane cascade. Constant temperature anemometry is used for transient data acquisition. An inlet grid induces turbulence and a radial total pressure profile across the channel height.