Cabin air compressor with liquid cooled passage formed in the case

1. A cabin air compressor (CAC) of an aircraft environmental control system, the CAC comprising:

a CAC case defining a forward end and an aft end axially spaced apart from the forward end,

wherein the CAC case defines an outer shell that extends axially along CAC case, and

wherein the CAC includes:

an inlet portion that extends aft of the forward end;

a compressor rotor portion located aft of the inlet portion;

a forward bearing portion located aft of the compressor rotor portion;

a motor portion that is surrounded by the outer shell of the CAC case and is located aft of the compressor rotor portion,

wherein the motor portion of the CAC is axially along a rotor and stator supported within the CAC case, wherein the stator is radially exterior to the rotor;

an aft bearing portion located aft of the motor portion, that extends to the aft end of the CAC case, wherein the aft bearing portion includes a thrust bearing that is rotationally supported at the aft end of the CAC case;

a motor cooling circuit including: a bleed channel defined in the inlet portion; a motor cooling inlet channel defined in the aft bearing portion of the CAC, and a motor cooling duct extending between the bleed channel and the motor cooling inlet channel,

wherein the motor cooling duct is radially exterior to the outer shell of the CAC case along the motor portion of the CAC;

a bearing cooling inlet channel defined at the aft end of the CAC case, aft of the motor portion, the bearing cooling inlet channel being configured to direct cooling air into the aft bearing portion and toward the thrust bearing; and

a supplemental cooling passage formed in the outer shell of the CAC case, at the aft bearing portion and extending along the motor portion, toward the forward bearing portion of the CAC,

wherein:

an aft portion of the supplemental cooling passage, located aft of the motor portion, forms an aft passage that surrounds the bearing cooling inlet channel;

a forward portion of the supplemental cooling passage is defined along the motor portion of the CAC case,

wherein the forward portion includes a forward passage that is formed in the outer shell of the CAC case and surrounds the motor portion of the CAC,. and the forward passage is radially exterior to the stator; and

the supplemental cooling passage is configured to direct a supplemental cooling medium therethrough.

2. The CAC of claim 1 , wherein:

the supplemental cooling medium is a liquid.

3. The CAC of claim 1 , wherein:

an inlet channel of the supplemental cooling passage is formed at the aft portion of the supplemental cooling passage, wherein the inlet channel is configured to direct the supplemental cooling medium into the supplemental cooling passage.

4. The CAC of claim 1 , wherein:

the forward passage and the aft passage of the supplemental cooling passage extend along respective axes that are normal to each other.

5. The CAC of claim 1 , wherein:

an outlet channel for the supplemental cooling passage is defined at a forward end of the supplemental cooling passage, located adjacent a forward end of the motor portion of the CAC.

6. The CAC of claim 5 , wherein:

the inlet and the outlet channels respectively include quick release adaptors.

7. The CAC of claim 1 , wherein:

the supplemental cooling passage terminates aft of the forward bearing portion.

8. The CAC of claim 1 , wherein:

a forward journal bearing of the forward bearing portion is rotationally supported between a forward stationary member of the CAC case and a forward motor shaft operationally connected to a motor; and

an aft journal bearing of the aft bearing portion is rotationally supported between an aft stationary member of the CAC case and an aft motor shaft operationally connected to the motor.

9. The CAC of claim 8 , wherein:

the thrust bearing is rotationally supported between the aft end of the CAC case and the aft motor shaft.

10. An aircraft, comprising:

an environmental control system, including the CAC of claim 1 .