Gas turbine engine and method for reducing nonvolatile particulate matter emissions in the exhaust
A gas turbine engine has a first subset of fuel spray nozzles and a second subset of fuel spray nozzles. A combustor is operable with the first subset of fuel spray nozzles supplied with fuel at a greater flow rate than each of the second subset of fuel spray nozzles. A ratio of the first subset of fuel spray nozzles to the second subset of fuel spray nozzles is 1:2 to 1:5. A first idle-MTO nvPM emissions index ratio is: EI idle EI max TO , where: EI idle is the nvPM emissions index in mg/kg operating at around 7% available thrust; EI maxTO is the nvPM emissions index in mg/kg of the gas turbine engine operating at around 100% available thrust; and the first idle-MTO nvPM emissions index ratio of the gas turbine engine is less than 60. A sustainable aviation fuel (SAF) can be provided to the fuel spray nozzles.
1 . A gas turbine engine for an aircraft, comprising:
a combustor, comprising a combustion chamber and a plurality of fuel spray nozzles configured to inject fuel into the combustion chamber, wherein the plurality of fuel spray nozzles comprises a first subset of fuel spray nozzles and a second subset of fuel spray nozzles, wherein the combustor is operable in a condition in which each of the fuel spray nozzles of the first subset of fuel spray nozzles is supplied with fuel at a greater fuel flow rate than each of the fuel spray nozzles of the second subset of fuel spray nozzles, wherein a ratio of the number of fuel spray nozzles in the first subset of fuel spray nozzles to the number of fuel spray nozzles in the second subset of fuel spray nozzles is in the range of 1:2 to 1:5; and
wherein:
a first idle-maximum take-off (MTO) non-volatile particulate matter (nvPM) emissions index ratio is defined as:
EI
idle
EI
max
TO
where:
EI idle is the nvPM emissions index in mg/kg of the gas turbine engine if operating at around 7% available thrust for given operating conditions; and
EI maxTO is the nvPM emissions index in mg/kg of the gas turbine engine if operating at around 100% available thrust for the given operating conditions:
the first idle-MTO nvPM emissions index ratio of the gas turbine engine is less than 60; and
the gas turbine engine is configured to provide fuel comprising a sustainable aviation fuel (SAF) to the plurality of fuel spray nozzles.
2 . The gas turbine engine of claim 1 wherein the first idle-MTO nvPM emissions index ratio is less than 58.4.
3 . The gas turbine engine of claim 1 , wherein the first idle-MTO nvPM emissions index ratio is less than or equal to 45.
4 . The gas turbine engine of claim 1 , wherein the first idle-MTO nvPM emissions index ratio is less than or equal to 8.65.
5 . The gas turbine engine of claim 1 , wherein the first idle-MTO nvPM emissions index ratio is greater than or equal to 0.038.
6 . The gas turbine engine ( 10 ) of claim 1 , wherein the first idle-MTO nvPM emissions index ratio is in the range of 0.038 to 8.65.
7 . The gas turbine engine of claim 1 , wherein:
a second idle-MTO nvPM emissions index ratio is defined as:
EI
idle
,
SAF
/
EI
max
TO
,
SAF
EI
idle
,
FF
/
EI
max
TO
,
FF
where:
EI idle,SAF is the nvPM emissions index in mg/kg of the gas turbine engine if operating at around 7% available thrust for the given operating conditions, or for other different operating conditions, and if a fuel provided to the combustor comprises a sustainable aviation fuel;
EI maxTO,SAF is the nvPM emissions index in mg/kg of the gas turbine engine if operating at around 100% available thrust for the same given operating conditions at which EI idle,SAF is calculated, and if a fuel provided to the combustor comprises a sustainable aviation fuel;
EI idle,FF is the nvPM emissions index in mg/kg of the gas turbine engine if operating at around 7% available thrust for the same given operating conditions at which EI idle,SAF is calculated, and if a fuel provided to the combustor is a fossil-based hydrocarbon fuel;
EI maxTO,FF is the nvPM emissions index in mg/kg of the gas turbine engine if operating at around 100% available thrust for the same given operating conditions at which EI idle,SAF is calculated, and if a fuel provided to the combustor is a fossil-based hydrocarbon fuel; and the second idle-MTO nvPM emissions index ratio of the gas turbine engine is less than 1.
8 . The gas turbine engine of claim 7 , wherein the second idle-MTO nvPM emissions index ratio is less than or equal to 0.8.
9 . The gas turbine engine of claim 7 , wherein the second idle-MTO nvPM emissions index ratio is less than or equal to 0.178.
10 . The gas turbine engine of claim 7 , wherein the second idle-MTO nvPM emissions index ratio is greater than or equal to 0.118.
11 . The gas turbine engine of claim 7 , wherein the second idle-MTO nvPM emissions index ratio is in the range 0.118 to 0.178.
12 . The gas turbine engine of claim 1 , wherein the ratio of the number of fuel spray nozzles in the first subset of fuel spray nozzles to the number of fuel spray nozzles in the second subset of fuel spray nozzles is in the range of 1:3 to 1:4.
13 . The gas turbine engine of claim 1 , wherein the first subset of fuel spray nozzles includes between 1 and 10 fuel spray nozzles.
14 . The gas turbine engine of claim 1 , wherein the second subset of fuel spray nozzles includes between 10 and 25 fuel spray nozzles.
15 . The gas turbine engine of claim 1 , wherein the combustor comprises one or more ignitors.
16 . The gas turbine engine of claim 15 , wherein each of the first subset of fuel spray nozzles is located nearer a respective one or more of the ignitors than the second subset, and/or wherein one or more of the ignitors is arranged diametrically opposite another one or more of the ignitors.
17 . The gas turbine engine of claim 1 , wherein the fuel provided to the combustor comprises a % SAF in the range of 50% to 100%.
18 . A method of operating the gas turbine engine of claim 1 , the method comprising providing fuel comprising a sustainable aviation fuel to the plurality of fuel spray nozzles.
19 . A method of operating a gas turbine engine, the gas turbine engine comprising:
a combustor, comprising a combustion chamber and a plurality of fuel spray nozzles configured to inject fuel into the combustion chamber, wherein the plurality of fuel spray nozzles comprises a first subset of fuel spray nozzles and a second subset of fuel spray nozzles, wherein the combustor is operable in a condition in which each of the fuel spray nozzles of the first subset of fuel spray nozzles is supplied with fuel at a greater fuel flow rate than each of the fuel spray nozzles of the second subset of fuel spray nozzles, wherein a ratio of the number of fuel spray nozzles in the first subset of fuel spray nozzles to the number of fuel spray nozzles in the second subset of fuel spray nozzles is in the range of 1:2 to 1:5; and
wherein:
a first idle-maximum take-off (MTO) non-volatile particulate matter (nvPM) emissions index ratio is defined as:
EI
idle
EI
max
TO
where:
EI idle is the nvPM emissions index in mg/kg of the gas turbine engine operating at around 7% available thrust for given operating conditions; and
EI maxTO is the nvPM emissions index in mg/kg of the gas turbine engine operating at around 100% available thrust for the given operating conditions; and
the first idle-MTO nvPM emissions index ratio of the gas turbine engine is less than 60; and
the method comprises providing fuel comprising a sustainable aviation fuel to the plurality of fuel spray nozzles.
20 . The method of claim 19 , wherein:
a second idle-MTO nvPM emissions index ratio is defined as:
EI
idle
,
SAF
/
EI
max
TO
,
SAF
EI
idle
,
FF
/
EI
maxTO
,
FF
where:
EI idle,SAF is the nvPM emissions index in mg/kg of the gas turbine engine operating at around 7% available thrust for the given operating conditions, or for other different operating conditions, and a fuel provided to the combustor comprises a sustainable aviation fuel;
EI maxTO,SAF is the nvPM emissions index in mg/kg of the gas turbine engine operating at around 100% available thrust for the same given operating conditions at which EI idle,SAF is calculated, and a fuel provided to the combustor comprises a sustainable aviation fuel;
EI idle,FF is the nvPM emissions index in mg/kg of the gas turbine engine operating at around 7% available thrust for the same given operating conditions at which EI idle,SAF is calculated, and a fuel provided to the combustor is a fossil-based hydrocarbon fuel;
EI maxTO,FF is the nvPM emissions index in mg/kg of the gas turbine engine operating at around 100% available thrust for the same given operating conditions at which EI idle,SAF is calculated, and a fuel provided to the combustor is a fossil-based hydrocarbon fuel; and
the second idle-MTO nvPM emissions index ratio of the gas turbine engine is less than 1.