# US 12,180,853 B2 · Combination seal for a supercritical carbon dioxide turbo generator

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- Number: US 12,180,853 B2
- Document ID: US12180853B2
- Status: Granted
- Kind: B2
- Application number: 18/364,302
- Filed: 2023-08-02
- Published: 2024-01-18
- Granted: 2024-12-31
- Earliest claimed: 2020-12-22
- Assignees: Hamilton Sundstrand Corporation
- Applicants: Hamilton Sundstrand Corporation
- Inventors: Brian M. Holley; Malcolm MacDonald; Duane C. McCormick
- Web page: https://patentgrep.com/patent/US12180853B2

## CPC

- F01D 25/12: Cooling
- F01D 11/02: by non-contact sealings, e.g. of labyrinth type (for sealing space between rotor blade tips and stator F01D11/08)
- F01D 11/025: {Seal clearance control; Floating assembly; Adaptation means to differential thermal dilatations}
- F01D 15/10: Adaptations for driving, or combinations with, electric generators
- F01D 25/125: {of bearings}
- F01K 25/103: {Carbon dioxide (F01K25/065 takes precedence)}
- F01K 7/32: the engines using steam of critical or overcritical pressure
- F05D 2220/76: an electrical generator
- F05D 2240/55: Seals
- F05D 2260/20: Heat transfer, e.g. cooling
- F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D)
- F01K: STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES (gas-turbine or jet-propulsion plants F02; nuclear power plants, engine arrangements therein G21D)
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS

## Abstract

A turbo generator rotor assembly is provided and includes a generator, first and second bearings on a compressor-side and a turbine-side of the generator and a combination seal configuration in which leakage from the compressor cools the first bearing, the generator and the second bearing. The combination seal configuration leads to minimal leakage past the turbine with the generator and the first and second bearings being cooled with leakage flow from the compressor.

## Claims

### Claim 1

A method of operating a super-critical carbon dioxide (sCO2) turbo generator rotor assembly with a generator operably interposed between a compressor and a turbine, the method comprising:
directing leakage from the compressor through a first bearing on a compressor-side of the generator, around the generator and through a second bearing on a turbine-side of the generator; and
redirecting the leakage from the compressor and leakage from a turbine as egress from the second bearing to a pump,
wherein the directing of the leakage from the compressor comprises:
determining an operating condition of the sCO2 turbo generator rotor assembly; and
adjusting the leakage from the compressor to achieve a balance of generator efficiency and a parasitic pumping loss for the operating condition.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the adjusting of the leakage from the compressor comprises:
increasing a flow rate of the leakage from the compressor to increase the generator efficiency; and
decreasing the flow rate of the leakage from the compressor to reduce the parasitic pumping loss.

### Claim 3 (depends on 2)

The method according to claim 2, wherein the adjusting of the leakage from the compressor further comprises controlling the flow rate of the leakage from the compressor based on a power condition.

### Claim 4

A method of operating a super-critical carbon dioxide (sCO2) turbo generator rotor assembly with a generator operably interposed between a compressor and a turbine, the method comprising:
directing leakage from the compressor through a first bearing on a compressor-side of the generator, around an exterior of the generator and through a second bearing on a turbine-side of the generator; and
redirecting the leakage from the compressor and leakage from a turbine as egress from the second bearing to a pump,
wherein the directing of the leakage from the compressor comprises:
determining an operating condition of the sCO2 turbo generator rotor assembly; and
adjusting the leakage from the compressor to achieve a balance of generator efficiency and a parasitic pumping loss for the operating condition.

### Claim 5 (depends on 4)

The method according to claim 4, wherein the adjusting of the leakage from the compressor comprises:
increasing a flow rate of the leakage from the compressor to increase the generator efficiency; and
decreasing the flow rate of the leakage from the compressor to reduce the parasitic pumping loss.

### Claim 6 (depends on 5)

The method according to claim 5, wherein the adjusting of the leakage from the compressor further comprises controlling the flow rate of the leakage from the compressor based on a power condition.