The following components comprise the LPT nozzle assembly :
1. Air turbine interstage stationary seal
2. LP turbine nozzle segments
3. Forward turbine interstage stationary air seal
4. LP turbine rotor case
5. LP turbine shroud segment locking ring
6. LP turbine shroud segments
7. LP turbine shroud segment retaining ring
The LPt nozzle assembly introduces HP turbine exhaust gases (core air) to the LPT rotor assembly at the proper angle for maximum turbine performance.
It controls core airflow leakage at the tips of the turbine blades by providing a close tolerance fit between the turbine blade tips and the shroud segments that line the rear of the rotor case.
The nozzle assembly passes cooling air through airfoil cores from the compressor to the rotor assembly for cavity purging,and cooling to the HP turbine disk and LP turbine blades.
Core, Secondary and bypass airflows are interstaged throughout the explanation and detailed in the module operation section.