Airgap cooling system for an electric machine

An electric machine defining an axial direction, a radial direction, and a circumferential direction, the electric machine comprising:

• a shaft rotating about the axial direction;
• a rotor assembly mechanically coupled to the shaft;
• a stator assembly surrounding the rotor assembly and being spaced apart from the rotor assembly along the radial direction to define an airgap therebetween, the stator assembly further comprising a lamination stack defining a distribution passage that extends through the lamination stack from an axial end face of the lamination stack, the lamination stack further defining a discharge passage that extends between the distribution passage and the airgap;
• and
• a cooling manifold positioned at the axial end face of the lamination stack and defining a distribution plenum in fluid communication with the distribution passage, wherein the cooling manifold is configured for receiving a cooling fluid and directing the cooling fluid into the distribution plenum, through the distribution passage and the discharge passage, and into the airgap,
• wherein the discharge passage is angled relative to the radial direction.

An electric machine defining an axial direction, a radial direction, and a circumferential direction, the electric machine comprising:

• a shaft rotating about the axial direction;
• a rotor assembly mechanically coupled to the shaft;
• a stator assembly surrounding the rotor assembly and being spaced apart from the rotor assembly along the radial direction to define an airgap therebetween, the stator assembly further comprising a lamination stack defining a distribution passage that extends through the lamination stack from an axial end face of the lamination stack, the lamination stack further defining a discharge passage that extends between the distribution passage and the airgap;
• a cooling manifold positioned at the axial end face of the lamination stack and defining a distribution plenum in fluid communication with the distribution passage, wherein the cooling manifold is configured for receiving a cooling fluid and directing the cooling fluid into the distribution plenum, through the distribution passage and the discharge passage, and into the airgap;
• a cooling jacket positioned around an outer radial surface of the stator assembly and defining a cooling channel;
• and
• a cooling fluid supply in fluid communication with the cooling channel of the cooling jacket to provide a secondary cooling fluid through the cooling jacket,
• wherein the cooling manifold is formed at least in part by the cooling jacket.

An airgap cooling system for an electric machine, the electric machine comprising a rotor assembly rotatably mounted within a stator assembly and defining an airgap therebetween, wherein the stator assembly comprises a lamination stack, the airgap cooling system comprising:

• a plurality of distribution passages that extend through the lamination stack from an axial end face of the lamination stack;
• a plurality of discharge passages that extend between the plurality of distribution passages and the airgap;
• a cooling manifold positioned at an axial end face of the lamination stack and defining an annular distribution plenum in fluid communication with the plurality of distribution passages, wherein the cooling manifold is configured for receiving a cooling fluid and directing the cooling fluid into the distribution plenum, through the plurality of distribution passages and the plurality of discharge passages, and into the airgap,
• wherein the cooling manifold is configured for receiving the cooling fluid from a cooling fluid supply that is fluidly coupled to the cooling manifold, wherein the cooling fluid supply comprises a compressor bleed source of a gas turbine engine.