Jet engine inlet-fan system and design method
A supersonic aircraft engine axial fan that includes a rotating blade row having blades that receive a supersonic entry flow in the absolute frame and decelerate the flow to a lower supersonic or subsonic velocity exit flow while adding work to the flow to increase stagnation pressure. It is preferred that the lower velocity be subsonic. When the fan is combined with a suitably designed inlet, the propulsion system is compact and lighter in weight than conventional engines for supersonic aircraft.
1. An axial fan comprising:
a rotating blade row including blades that receive an absolute supersonic freestream entry flow in an absolute, non-rotating reference frame over some part or all of the span and decelerate the flow to a subsonic velocity exit flow while adding work to the flow to increase stagnation pressure.
2. The fan of claim 1 further including a low total pressure loss inlet preceding the rotating blade row.
3. The fan of claim 2 wherein the inlet decelerate the flow to a Mach number in the range of about 1.2—about 1.3 at fan entry.
4. The fan of claim 3 wherein the inlet creates a series of near-isentropic weak shock waves to decelerate the flow.
5. The fan of claim 1 wherein the blade configuration results in a series of shock waves to decelerate the flow.