# US 10,371,055 B2 · Intercooled cooling air using cooling compressor as starter

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- Number: US 10,371,055 B2
- Document ID: US10371055B2
- Status: Granted
- Kind: B2
- Application number: 14/837,009
- Filed: 2015-08-27
- Published: 2016-08-18
- Granted: 2019-08-06
- Earliest claimed: 2015-02-12
- Assignees: United Technologies Corporation
- Applicants: United Technologies Corporation
- Inventors: Nathan Snape; Gabriel L. Suciu; Brian D. Merry
- Web page: https://patentgrep.com/patent/US10371055B2

## CPC

- F02C 7/185: {Cooling means for reducing the temperature of the cooling air or gas}
- F02C 3/04: having a turbine driving a compressor (power transmission arrangements F02C7/36; control of working fluid flow F02C9/16)
- F02C 6/08: the gas being bled from the gas-turbine compressor
- F02C 7/277: the starter being a {separate} turbine
- F02C 7/32: Arrangement, mounting, or driving, of auxiliaries
- F02K 3/025: {the by-pass flow being at least partly used to create an independent thrust component}
- F02K 3/075: controlling flow ratio between flows
- F05D 2260/213: by the provision of a heat exchanger within the cooling circuit
- Y02T 50/60: Efficient propulsion technologies, e.g. for aircraft
- F02C: GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS (construction of turbines F01D; jet-propulsion plants F02K; construction of compressors or fans F04; generating combustion products of high pressure or high velocity F23R; using gas turbines in compression refrigeration plants F25B11/00)
- F02K: JET-PROPULSION PLANTS (features of jet-propulsion plants common to gas-turbine plants, air intakes or fuel supply control of air-breathing jet-propulsion plants F02C7/00, F02C9/00)
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A gas turbine engine comprises a main compressor section having a high pressure compressor with a downstream discharge, and more upstream locations. A turbine section has a high pressure turbine. A tap taps air from at least one of the more upstream locations in the compressor section, passes the tapped air through a heat exchanger and then to a cooling compressor. The cooling compressor compresses air downstream of the heat exchanger, and delivers air into the high pressure turbine. The cooling compressor is connected to be driven with at least one rotor in the main compressor section. A source of pressurized air is selectively sent to the cooling compressor to drive a rotor of the cooling compressor to rotate, and to in turn drive the at least one rotor of the main compressor section at start-up of the gas turbine engine. An intercooling system is also disclosed.

## Claims

### Claim 1

A gas turbine engine comprising;
a main compressor section having a high pressure compressor with a downstream discharge, and more upstream locations; a turbine section having a high pressure turbine;
a tap tapping air from at least one of the more upstream locations in the compressor section, passing the tapped air through a heat exchanger and then to a cooling compressor, the cooling compressor compressing air downstream of the heat exchanger, and delivering air into the high pressure turbine;
the cooling compressor being connected to be driven with at least one rotor in the main compressor section, and a source of pressurized air that is selectively sent to the cooling compressor, to drive a rotor of the cooling compressor to rotate, to in turn drive the at least one rotor of the main compressor section at start-up of the gas turbine engine;
the source of pressurized air is an auxiliary power unit;
a cooling compressor valve that is movable between two positions, with a first position delivering air from the cooling compressor to the high pressure turbine, and in a second position delivering the pressurized air from the auxiliary power unit to the rotor of the cooling compressor; and
a precooler that receives air from the main compressor section, and cools the air to be delivered to an associated aircraft, and a precooler valve that is movable between two positions, with a first position allowing air from the precooler to move through said precooler valve and downstream to the aircraft, and in a second position, blocking flow of the air from the precooler to the aircraft, and allowing the pressurized air from the auxiliary power unit to pass through said precooler valve and to the cooling compressor valve.

### Claim 2 (depends on 1)

The gas turbine engine as set forth in claim 1, wherein the rotor of the cooling compressor includes a centrifugal compressor impeller.

### Claim 3 (depends on 2)

The gas turbine engine as set forth in claim 2, wherein air temperatures at the downstream discharge of the high pressure compressor are greater than or equal to 1350° F.

### Claim 4 (depends on 3)

The gas turbine engine as set forth in claim 3, wherein the turbine section drives a bull gear, the bull gear further driving the impeller of the cooling compressor.

### Claim 5 (depends on 1)

The gas turbine engine as set forth in claim 1, wherein an APU valve is movable between two positions to selectively block or allow flow of the air from the precooler valve to the aircraft, when the precooler valve is in said first position or to selectively allow the pressurized air from the auxiliary power unit to pass to the precooler valve, when the precooler valve is in said second position.

### Claim 6 (depends on 5)

The gas turbine engine as set forth in claim 5, wherein an impeller valve is positioned between the heat exchanger and the rotor of the cooling compressor, and the impeller valve being selectively movable between two positions, with a first position allowing air from the heat exchanger to pass to the rotor of the cooling compressor, and a second position allowing the pressurized air having driven the rotor of the cooling compressor to be dumped to atmosphere, and air passing through said impeller valve from the heat exchanger to the cooling compressor when the impeller valve is in said first position, and the pressurized air having driven the rotor of the cooling compressor passing through said impeller valve in said second position to be dumped to atmosphere.

### Claim 7 (depends on 2)

The gas turbine engine as set forth in claim 2, wherein the impeller is provided with variable vanes to direct air to the impeller in a desired direction when the rotor of the cooling compressor is being driven to rotate by the pressurized air.

### Claim 8 (depends on 1)

The gas turbine engine as set forth in claim 1, wherein an APU valve is movable between two positions to selectively block or allow flow of the air from the precooler valve to the aircraft, when the precooler valve is in said first position or to selectively allow the pressurized air from the source to pass to the precooler valve, when the precooler valve is in said second position.

### Claim 9 (depends on 1)

The gas turbine engine as set forth in claim 1, wherein an impeller valve is positioned between the heat exchanger and the rotor of the cooling compressor, and the impeller valve being selectively movable between two positions, with a first position allowing air from the heat exchanger to pass to the rotor of the cooling compressor, and a second position allowing the pressurized air having driven the rotor of the cooling compressor to be dumped to atmosphere, and air passing through said impeller valve from the heat exchanger to the cooling compressor when the impeller valve is in said first position, and the pressurized air having driven the rotor of the cooling compressor passing through said impeller valve in said second position to be dumped to atmosphere.

### Claim 10

An intercooling system for a gas turbine engine comprising:
a heat exchanger for cooling air drawn from a portion of a main compressor section at a first temperature and pressure for cooling the air to a second temperature cooler than the first temperature;
a cooling compressor compressing air communicated from the heat exchanger to a second pressure greater than the first pressure and communicating the compressed air to a portion of a turbine section;
the cooling compressor being connected to be driven by a rotor of the main compressor section, and a source of pressurized air that is selectively sent to the cooling compressor, to drive a rotor of the cooling compressor to rotate, to in turn drive the rotor of the main compressor section at start-up of an associated gas turbine engine;
a cooling compressor valve that is movable between two positions, with a first position delivering air from the cooling compressor to the turbine section, and in a second position delivering pressurized air from the source to the rotor of the cooling compressor; and
a precooler valve that is movable between two positions, with a first position allowing air from a precooler to move through said precooler valve and downstream to an aircraft, and in a second position, blocking flow of the air from the precooler to the aircraft, and allowing pressurized air from the source to pass through said precooler valve and to the cooling compressor valve.

### Claim 11 (depends on 10)

The intercooling system as set forth in claim 10, wherein the rotor of the cooling compressor includes a centrifugal compressor impeller.

### Claim 12 (depends on 11)

The intercooling system as set forth in claim 11, wherein the impeller is provided with variable vanes to direct air to the impeller in a desired direction when the rotor of the cooling compressor is being driven to rotate by the pressurized air.

### Claim 13 (depends on 10)

The intercooling system for as set forth in claim 10, wherein an impeller valve is positioned between the heat exchanger and the rotor of the cooling compressor, and the impeller valve being selectively movable between two positions, with a first position allowing air from the heat exchanger to pass to the rotor of the cooling compressor, and a second position allowing the pressurized air having driven the rotor of the cooling compressor to be dumped to atmosphere, and air passing through said impeller valve from the heat exchanger to the cooling compressor when the impeller valve is in said first position, and the pressurized air having driven the rotor of the cooling compressor passing through said impeller valve in said second position to be dumped to atmosphere.