Modular cabin blower system for aircraft
A gas turbine engine includes an engine core including a compressor, a combustor, and a turbine, the compressor being connected to the turbines through a respective shaft; and a cabin blower system comprising: an electric variator comprising a first electrical machine connected to a first shaft arranged along a first axis, a second electrical machine connected to a second shaft arranged along a second axis, and a power management system; a cabin blower comprising a compressor driven by a third shaft arranged along a third axis, the compressor comprising an air inlet and an air outlet; and a differential gearbox. The gas turbine engine further includes an accessory gearbox arranged within an accessory gearbox casing and adapted to drive the cabin blower system.
1. A gas turbine engine including:
an engine core including a compressor, a combustor, and a turbine, the compressor being connected to the turbine through a respective shaft;
an accessory gearbox arranged within an accessory gearbox casing that surrounds the accessory gearbox, a first axis passing through the accessory gearbox to define a first axial side of the accessory gearbox casing and a second axial side of the accessory gearbox casing opposite the first axial side; and
a cabin blower system adapted to be driven by the accessory gearbox and comprising:
an electric variator comprising a first electrical machine connected to a drive pad of the accessory gearbox by a first shaft arranged along the first axis, a second electrical machine connected to a second shaft arranged along a second axis, wherein the second shaft is arranged outside the accessory gearbox and does not pass through the accessory gearbox casing, and a power management system interconnecting the first and second electrical machines and controlling whether each of the first and second electrical machines operates as a motor or a generator;
a differential gearbox having a first input connected to the drive pad of the accessory gearbox to receive drive therefrom, a second input connected to the second shaft of the second electrical machine, and an output; and
a cabin blower comprising a cabin blower compressor driven by the output of the differential gearbox by a third shaft arranged along a third axis, wherein the third shaft passes all the way through the accessory gearbox casing from the first axial side to the second axial side, the cabin blower compressor comprising an air inlet and an air outlet;
wherein the cabin blower, the first electrical machine, the second electrical machine, and the differential gearbox are configured as modules, and
wherein the first and second electrical machines are arranged on the first axial side of the accessory gearbox casing and the cabin blower is arranged on the second axial side of the accessory gearbox casing opposite the first axial side.
2. The gas turbine engine of claim 1 , wherein the first and second electrical machines are ganged and the first and second shafts are coaxial with the drive pad of the accessory gearbox.
3. The gas turbine engine of claim 1 , wherein the differential gearbox is an epicyclic gearbox comprising a summing gearbox and a step-up, amplifying gearbox.
4. The gas turbine engine of claim 3 , wherein the summing gearbox is an epicyclic gearbox in a planetary arrangement and comprises a sun gear, a plurality of planet gears, a carrier connecting the planet gears, and a ring gear.
5. The gas turbine engine of claim 4 , wherein the first shaft connects the accessory gearbox and the first electrical machine to drive the planet gears through the carrier, and the second shaft connects the second electrical machine to the sun gear of the summing gearbox.
6. The gas turbine engine of claim 5 , wherein the step-up, amplifying gearbox is an epicyclic gearbox in a star arrangement and comprises a sun gear connected to the third shaft to drive the cabin blower.
7. The gas turbine engine of claim 1 , wherein the first and second electrical machines are independently configured to work as electric motors and/or as power generators.
8. The gas turbine engine of claim 1 , comprising a fan air offtake adapted to feed air to the cabin blower through the air inlet.
9. The gas turbine engine of claim 8 , comprising a bypass duct, and wherein the fan air offtake is arranged in the bypass duct.
10. The gas turbine engine of claim 9 , further comprising a bifurcation, or splitter, spanning the bypass duct and comprising a leading edge, a trailing edge and a first sidewall and a second sidewall connecting the leading edge and the trailing edge, wherein the fan air offtake is either a forward facing offtake arranged on the bifurcation leading edge, or a scoop on either the first or second sidewalls of the bifurcation.
11. The gas turbine engine of claim 1 , further comprising a heat exchanger to cool the cabin blower system, wherein the heat exchanger is either a surface heat exchanger or a matrix cooler.
12. The gas turbine engine of claim 11 , wherein the heat exchanger is a surface heat exchanger mounted from fairings of the engine core.
13. The gas turbine engine of claim 1 , wherein the cabin blower compressor of the cabin blower is a dual impeller, mounted from the accessory gearbox casing.
14. An aircraft comprising the gas turbine engine of claim 1 .