Unsteady Interaction Between a Transonic Turbine Stage and Downstream Components

[摘要] Results from a numerical simulation of the unsteady flowthrough one quarter of the circumference of a transonichigh-pressure turbine stage, transition duct, and low-pressureturbine first vane are presented and compared withexperimental data. Analysis of the unsteady pressure field resultingfrom the simulation shows the effects of not only therotor/stator interaction of the high-pressure turbine stagebut also new details of the interaction between the blade andthe downstream transition duct and low-pressure turbinevane. Blade trailing edge shocks propagate downstream,strike, and reflect off of the transition duct hub and/or downstreamvane leading to high unsteady pressure on thesedownstreamcomponents. The reflection of these shocks from the downstream components back into the blade itself hasalso been found to increase the level of unsteady pressurefluctuations on the uncovered portion of the blade suctionsurface. In addition, the blade tip vortex has been found tohave a moderately strong interaction with the downstreamvane even with the considerable axial spacing between thetwo blade-rows. Fourier decomposition of the unsteady surfacepressure of the blade and downstream low-pressure turbinevane shows the magnitude of the various frequenciescontributing to the unsteady loads. Detailed comparisonsbetween the computed unsteady surface pressure spectrumand the experimental data are shown along with a discussionof the various interaction mechanisms between the blade,transition duct, and downstream vane. These comparisonsshow-overall good agreement between the simulation and experimentaldata and identify areas where further improvementsin modeling are needed.

[学科分类] 力学，机械学