MULTISTAGE TURBINE SIMULATIONS WITH VORTEX-BLADE INTERACTION

The average passage approach of Adamczyk et al. (1990) has been used t o simulate the multistage environment of the General Electric E(3) low -pressure turbine. Four configurations have been analyzed and compared to test data. These include the nozzle only, the first stage, the fir st stage and a half, and the first two stages. A high casing slope on the first-stage nozzle causes the secondary flow vortex to separate of f the casing and enter the downstream rotor. The detrimental effect on performance dice to this vortex interaction has been predicted by the above approach, whereas isolated blade row calculations cannot simula te this interaction. The unsteady analysis developed by Chen et al. (1 994) has also been run to understand the unsteady pow field in the fir st-stage rotor and compare with the average passage model and test dat a. Comparisons of both the steady and unsteady analyses with data are generally good, although in the region near the casing of the shrouded rotors, the predicted loss is lower than that shown by the data.