US 12,607,145 B2Granted

Operating a gas turbine engine

AssigneeROLLS-ROYCE plc

InventorsAndrea Minelli, Craig W Bemment, Benjamin J Keeler, Kevin R Mcnally, Martin K Yates

Life of this patent

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Abstract

A method of operating an aircraft gas turbine engine including: a core including a turbine, a compressor, a combustor to combust fuel, and a core shaft connecting the turbine to the compressor; a fan upstream of the core; a fan shaft; a bearing supporting the fan shaft; an oil loop system supplying oil to the bearing; and a heat exchange system including: an air-oil heat exchanger through which oil in the oil loop system flows; and a fuel-oil heat exchanger through which oil in the oil loop system and fuel flow to transfer heat between the oil and the fuel; and a bypass pipe to allow a proportion of the oil to flow past one of the air-oil and the fuel-oil heat exchanger; and a bypass valve to allow the proportion of the oil sent through the bypass pipe to be varied.

Claims20

Dependent claims

A method of operating a gas turbine engine, the gas turbine engine comprising:

an engine core comprising a turbine, a compressor, a combustor arranged to combust a fuel, and a core shaft connecting the turbine to the compressor;
a fan located upstream of the engine core;
a fan shaft;
at least one bearing arranged to support the fan shaft;
an oil loop system arranged to supply oil to the at least one bearing;
and
a heat exchange system comprising:
an air-oil heat exchanger through which the oil in the oil loop system flows;
and
a fuel-oil heat exchanger through which the oil in the oil loop system and the fuel flow such that heat is transferred between the oil and the fuel;
a bypass pipe arranged to allow a proportion of the oil to flow past one of the air-oil heat exchanger or the fuel-oil heat exchanger;
and
a bypass valve arranged to allow the proportion of the oil sent through the bypass pipe to be varied;
wherein
the air-oil heat exchanger is within the oil loop system between an outlet of the fuel-oil heat exchanger and an inlet of a sump and between an outlet of a second fuel-oil heat exchanger and the inlet of the sump,
the method comprising
flowing the fuel, which comprises sustainable aviation fuel, through the fuel-oil heat exchanger;
and
controlling the heat exchange system such that, under cruise conditions, a heat transfer ratio of:
rate
⁢
of
⁢
heat
⁢
transfer
⁢
from
⁢
oil
⁢
to
⁢
air
⁢
(
kJkg
-
1
)
rate
⁢
of
⁢
heat
⁢
transfer
⁢
from
⁢
oil
⁢
to
⁢
fuel
⁢
(
kJkg
-
1
)
is from 0 to 0.67.

59 more elements

A gas turbine engine for an aircraft comprising:

a controller;
an engine core comprising a turbine, a compressor, and a core shaft connecting the turbine to the compressor;
a fan located upstream of the engine core;
and
a fan shaft;
at least one bearing arranged to support the fan shaft;
an oil loop system arranged to supply oil to the at least one bearing;
and
a heat exchange system comprising:
an air-oil heat exchanger through which the oil in the oil loop system flows;
a fuel-oil heat exchanger through which the oil in the oil loop system and the fuel flow such that heat is transferred between the oil and the fuel;
a bypass pipe arranged to allow a proportion of the oil to flow past one of the air-oil heat exchanger or the fuel-oil heat exchanger;
and
a bypass valve arranged to allow the proportion of the oil sent through the bypass pipe to be varied, wherein
the air-oil heat exchanger is within the oil loop system between an outlet of the fuel-oil heat exchanger and an inlet of a sump and between an outlet of a second fuel-oil heat exchanger and the inlet of the sump, and
the controller is configured to control the heat exchange system such that, under cruise conditions when the fuel flowing through the fuel-oil heat exchanger comprises sustainable aviation, a heat transfer ratio of:
rate
⁢
of
⁢
heat
⁢
transfer
⁢
from
⁢
oil
⁢
to
⁢
air
⁢
(
kJkg
-
1
)
rate
⁢
of
⁢
heat
⁢
transfer
⁢
from
⁢
oil
⁢
to
⁢
fuel
⁢
(
kJkg
-
1
)
is from 0 to 0.67.

56 more elements

Dependencies are inferred from the claim text.

Facts

Application: 18/969,808Filed 5 Dec 2024 · continuation
Priority: GB 231912514 Dec 2023
Published: US 2025/0198338 A119 Jun 2025
Granted: 21 Apr 2026
Term ends: Not estimatedThe source records don’t support an estimate.

Classification15 codes

F02C 7/14
Cooling of plants: of fluids in the plant , e.g. lubricant or fuel
F02C 3/24
Using a special fuel, oxidant, or dilution fluid to generate the combustion products: the fuel or oxidant being liquid at standard temperature and…
F02C 7/06
Features, components parts, details or accessories, not provided for in, or of interest apart form groups F02C1/00 - F02C6/00; Air intakes for…:…
F02C 7/224
Fuel supply systems: heating fuel before feeding to the burner