turbine inlet vanes

nozzle diaphragm

The ring of stationary vanes directly ahead of the turbine wheel. The vanes in the nozzle diaphragm act as a series of converging ducts that accelerates the airflow as it leaves the combustors and directs the flow of hot gases into the turbine in the direction of maximum efficiency. Also known as turbine inlet vanes or a nozzle ring. See nozzle blades.