In various embodiments, the present invention provides a means for improving gas
turbine engine performance by applying fluid flow control to the inter-
turbine duct joining a high-pressure
turbine spool and an associated low-pressure turbine spool, allowing the low-pressure turbine spool to have a relatively larger
diameter than the high-pressure turbine spool. One or more unobstructed fluid flow paths between one or more boundary layer suction ports disposed within the upstream end of the outer-
body surface of the inter-turbine duct and the suction side of the associated low-pressure turbine
nozzle are provided. Advantageously, the natural static
pressure difference between these points results in a self-aspirating
assembly. The fluid flow control provided by the respective suction and blowing forces generated allows for a relatively larger
diameter low-pressure turbine spool and / or relatively fewer low-pressure turbine nozzles to be used than is possible with conventional systems, assemblies, and methods. Thus, a gas turbine engine weight savings and optimized performance may be achieved.