<p class="MsoNormal">The coolant purge flow from the wheel space cavity happens lagging effect during the turbine accleeraction procress. The lagging egress coolant flow influenece the aerodynamic performance and endwall cooling effectivesss of turbine acceleration process. The flow field and aerothermal performance of two-stage axial turbines combined with rim seal structures considering coolant purge flow lagging effect in the turbine acceleration process was numerically investigated using Unsteady Reynolds-Averaged Navier-Stokes (URANS) and SST turbulence model. The effects of lagging coolant purge flow across the rim seal on the turbine aerodynamics and endwall cooing effectivess was conducted. The obtained results show that the turbine endwall has the maximum averaged cooling effectivess in the turbine acceleration process without consideration of the coolant purge flow lagging time. The turbine endwall cooling effectiveness decreases with the coolant ourge flow lagging time increases at the same rotational speed and mainstream flow conditions. The output power of turbine increases with the increases of the coolant purge flow lagging time in the acceleration process. The turbine aerodynamic efficiency obtained the maximum value when the coolant purge flow laggin time equals 1.5s at the same rotational speed. The turbine aerodynamic efficient decreases with the decreases of the coolant purge flow lagging time. The mainstream gas ingestions and coolant purge flow egress across the rim seal of two-stage turbine wheel space cavity was analyzed. The detailed flow field of two-stage turbine considering interaction between the coolant purge flow and mainstream was also discussed. The present work provides the reference for the match design between the turbine through flow and secondary flow system.</p>

Numerical Investigations on the Aerodynamic Performance and Endwall Cooling Characteristics of Turbine During Acceleration Process With Lagging Effects

Paper Proceedings: https://asmedigitalcollection.asme.org/GT/GT2021/volume/84898

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