Patent ID: 8328542

Claim:
An axial flow positive displacement gas turbine engine component comprising: a rotor assembly extending from a fully axial flow inlet to a downstream axially spaced apart axial flow outlet, the rotor assembly including a main rotor and one or more gate rotors, the main and gate rotors being rotatable about parallel main and gate axes of the main and gate rotors respectively, the main and gate rotors having two or more main helical blades and two or more gate helical blades wound about the main and gate axes respectively, the main helical blades intermeshed with the gate helical blades, the main and gate helical blades extending radially outwardly from annular main and gate hubs circumscribed about the main and gate axes of the main and gate rotors, the axial flow inlet including intersecting main and gate annular openings extending radially between a casing surrounding the rotor assembly and the main and gate hubs respectively, central portions of the main helical blades extending axially and downstream and having a full radial height as measured radially outwardly from the main hub, an inlet transition section axially forward and upstream of the central portion, and the main helical blades transitioning from 0 radial height to a fully developed blade profiles having the full radial height as measured radially from the main hub in a downstream direction in the inlet transition section.