Environmental control systems
An aircraft propulsion system includes a gas turbine engine; an environmental control system (ECS); and a bleed flowpath from the gas turbine engine through the ECS. A turbine is along the bleed flowpath and a propulsion fan is mechanically coupled to the turbine to be driven by the turbine.
1. An aircraft propulsion system comprising:
a gas turbine engine;
an environmental control system (ECS); and
a bleed flowpath from the gas turbine engine through the ECS, and further comprising:
a turbine of the ECS along the bleed flowpath; and
a propulsion fan mechanically coupled to the turbine to be driven by the turbine to provide a propulsive thrust component parallel to a thrust component of the gas turbine engine.
2. The aircraft propulsion system of claim 1 wherein:
the turbine drives only the propulsion fan.
3. The aircraft propulsion system of claim 1 wherein the ECS has, sequentially along the bleed flowpath:
a primary heat exchanger;
a first leg of a reheater heat exchanger;
a first leg of a condenser heat exchanger;
a water collector;
a second leg of the reheater heat exchanger in heat exchange relation with the first leg of the reheater heat exchanger;
the turbine;
a second leg of the condenser heat exchanger in heat exchange relation with the first leg of the condenser heat exchanger; and
a load.
4. The aircraft propulsion system of claim 3 further comprising:
a valve-controlled bypass flowpath bypassing the turbine from downstream of the reheater heat exchanger second leg to upstream of the condenser heat exchanger second leg.
5. The aircraft propulsion system of claim 3 wherein:
the primary heat exchanger provides heat exchange between the bleed flowpath and a ram air flowpath.
6. The aircraft propulsion system of claim 3 wherein:
the load is a passenger cabin air source.
7. The aircraft propulsion system of claim 3 wherein:
the reheater heat exchanger is a plate-fin heat exchanger;
the condenser heat exchanger is a plate-fin heat exchanger; and
the water collector is a can-type collector.
8. The aircraft propulsion system of claim 1 wherein:
the ECS does not have a compressor along the bleed flowpath.
9. The aircraft propulsion system of claim 1 wherein:
the ECS does not have a secondary heat exchanger along the bleed flowpath.
10. The aircraft propulsion system of claim 1 wherein:
the turbine is a single stage turbine and the ECS does not have any other turbine along the bleed flowpath.
11. An aircraft including the aircraft propulsion system of claim 1 and further comprising:
a fuselage;
a wing extending from the fuselage;
an engine pylon mounting an engine nacelle of the gas turbine engine to the fuselage; and
a supplemental propulsion pylon mounting the turbine and propulsion fan to the fuselage.
12. The aircraft of claim 11 further comprising:
a ram air flowpath in heat exchange relation with the bleed flowpath.
13. The aircraft of claim 12 wherein:
the engine pylon mounts the engine nacelle to the fuselage via the wing; and
the supplemental propulsion pylon mounts the turbine and propulsion fan to the fuselage via the wing.
14. An aircraft including the aircraft propulsion system of claim 1 and further comprising:
a ram air flowpath in heat exchange relation with the bleed flowpath.
15. The aircraft of claim 14 wherein one or more of:
the ECS does not have a compressor along the bleed flowpath;
the turbine drives only the propulsion fan;
the ECS heat exchange relation is at a primary heat exchanger and the ECS does not have a secondary heat exchanger along the bleed flowpath and ram air flowpath; and
an electric fan drives air along the ram air flowpath.
16. A method for using the aircraft propulsion system of claim 1 in an aircraft, the method comprising:
running the gas turbine engine to draw in air, compress the air in a compressor section, mix the air with fuel, combust the mixed air and fuel forming combustion products, expand the combustion products in a turbine section to drive the compressor section, expel the combustion products to produce the thrust component to propel flight of the aircraft;
bleeding a bleed flow of compressed air from the gas turbine engine;
passing the bleed flow along the bleed flowpath; and
the bleed flow driving the turbine to drive the propulsion fan to provide said propulsive thrust component and help propel the flight of the aircraft.
17. The method of claim 16 further comprising:
bypassing the turbine to control air temperature delivered to a load of the ECS.
18. The method of claim 17 wherein:
a controller controls the engine and the bypassing to provide a desired net thrust of the propulsion fan and the gas turbine engine.
19. An aircraft propulsion system comprising:
a gas turbine engine;
an environmental control system (ECS); and
a bleed flowpath from the gas turbine engine through the ECS, and further comprising:
means for providing a supplemental thrust component parallel to a thrust component of the pas turbine engine, the means for providing the supplemental thrust component powered by the ECS.
20. The aircraft propulsion system of claim 19 wherein:
the means comprises a bleed-driven turbine.