Injection Coolant Isolation Curtain to Reduce Turbine Ingress Heating

The advanced strategy to reduce the turbine ingress heating and thus the coolant requirement by injecting a “coolant isolation curtain” was developed numerically using a 3-D CFD model under steady state conditions. The coolant isolation curtain was applied under the nozzle guide vane platform for the forward cavity of a turbine stage of a large gas turbine engine. Specifically, the isolation curtain serves to isolate the hot mainstream gas from the turbine outer region. For comparison purposes, when the baseline design and the injection curtain design have the same total coolant mass flow, the maximum temperature T*max of the injection curtain design was reduced by 0.23, 0.12 and 0.12, respectively, for the outer cavity, outer rotor adiabatic wall and outer stator adiabatic wall compared to that of the baseline design. Upon adjusting the feed slot coolant of the baseline design to match the outer cavity T*max , for example, of the injection curtain design, the reduction of dimensionless total coolant per stage from applying the injection curtain was estimated as 0.0038. Also a more uniform adiabatic wall temperature distribution along the outer rotor and stator surfaces was observed by using the coolant isolation curtain.Copyright © 2005 by ASME