Aircraft engine and method of operating aircraft engine for reducing nonvolatile particulate matter emissions
A gas turbine engine includes a combustor with a combustion chamber and fuel spray nozzles to inject fuel into the combustion chamber. The nozzles include a first and second subset. Each of the nozzles of the first subset is supplied with fuel at a greater flow rate than each of the second subset. A ratio of nozzles in the first subset to the second subset is 1:2 to 1:5. An MTO nvPM emissions index ratio-modified fuel flow is EI maxTO , SAF EI maxTO , FF × W f , maxTO . EI maxTO,SAF is nvPM emissions index in mg/kg of the engine operating at around 100% available thrust with sustainable aviation fuel. EI maxTO,FF is nvPM emissions index in mg/kg of the engine operating at around 100% available thrust with fossil-based hydrocarbon. W f,maxTO is mass flow rate of fuel to the nozzles in kg/s operating at around 100% available thrust. The MTO nvPM emissions index ratio-modified fuel flow in kg/s is less than 2.
1 . A gas turbine engine for an aircraft, comprising:
a fuel distribution system comprising a controller and a fuel metering unit; and
a combustor comprising a combustion chamber and a plurality of fuel spray nozzles, wherein
the plurality of fuel spray nozzles are configured to inject fuel into the combustion chamber with a total mass flow rate controlled by the fuel metering unit,
the plurality of fuel spray nozzles comprises a first subset of fuel spray nozzles and a second subset of fuel spray nozzles,
the combustor is operable so that each fuel spray nozzle of the first subset of fuel spray nozzles is supplied with a first portion of the fuel at a first mass flow rate,
each fuel spray nozzle of the second subset of fuel spray nozzles is supplied with a second portion of the fuel at a second mass flow rate, and the first mass flow rate is greater than the second mass flow rate,
a ratio of a number of the fuel spray nozzles of the first subset of fuel spray nozzles to a number of the fuel spray nozzles of the second subset of fuel spray nozzles is in a range of 1:2 to 1:5;
a maximum take-off (MTO) non-volatile particulate matter (nvPM) emissions index ratio-modified fuel flow rate in kg/s is defined as:
EI
maxTO
,
SAF
EI
maxTO
,
FF
×
W
f
,
maxTO
EI maxTO,SAF is nvPM emissions index in mg/kg of the gas turbine engine when operating at around 100% available thrust for given operating conditions, when the fuel provided to the plurality of fuel spray nozzles comprises a sustainable aviation fuel;
EI maxTO,FF is nvPM emissions index in mg/kg of the gas turbine engine when operating at around 100% available thrust for the given operating conditions, when the fuel provided to the plurality of fuel spray nozzles is a fossil-based hydrocarbon fuel;
W f,maxTO is a total mass flow rate in kg/s of the fuel provided to the plurality of fuel spray nozzles when the gas turbine engine is operating at around 100% available thrust for the given operating conditions;
the controller is configured to control the fuel metering unit to control the fuel comprising the sustainable aviation fuel and provided to the plurality of fuel spray nozzles to achieve around 100% available thrust for the given operating conditions;
the MTO nvPM emissions index ratio-modified fuel flow rate is less than 2 kg/s.
2 . The gas turbine engine of claim 1 , wherein the MTO nvPM emissions index ratio-modified fuel flow rate is less than 1.29 kg/s.
3 . The gas turbine engine of claim 1 , wherein the MTO nvPM emissions index ratio-modified fuel flow rate is less than or equal to 0.834 kg/s.
4 . The gas turbine engine of claim 1 , wherein:
a climb nvPM emissions index ratio-modified fuel flow rate is defined as:
EI
climb
,
SAF
EI
climb
,
FF
×
W
f
,
climb
EI climb,SAF is nvPM emissions index in mg/kg of the gas turbine engine when operating at around 85% available thrust for the given operating conditions, or for other different operating conditions, when the fuel provided to the plurality of fuel spray nozzles comprises the sustainable aviation fuel;
EI climb,FF is nvPM emissions index in mg/kg of the gas turbine engine when operating at around 85% available thrust for the same operating conditions at which EI climb,SAF is calculated, when the fuel provided to the plurality of fuel spray nozzles is the fossil-based hydrocarbon fuel;
W f,climb is total mass flow rate of the fuel provided to the plurality of fuel spray nozzles in kg/s when the gas turbine engine is operating at around 85% available thrust for the same operating conditions at which EI climb,SAF and EI climb,FF are calculated; and
the controller is configured to control the fuel metering unit to control the fuel comprising the sustainable aviation fuel and provided to the plurality of fuel spray nozzles to achieve around 85% available thrust for the given operating conditions or the other different operating conditions;
the climb nvPM emissions index ratio-modified fuel flow rate is less than 2 kg/s.
5 . The gas turbine engine of claim 4 , wherein the climb nvPM emissions index ratio-modified fuel flow rate in kg/s is less than 1.05.
6 . The gas turbine engine of claim 4 , wherein the climb nvPM emissions index ratio-modified fuel flow rate in kg/s is less than or equal to 0.498.
7 . The gas turbine engine of claim 1 , wherein:
an approach nvPM emissions index ratio-modified fuel flow rate is defined as:
EI
approach
,
SAF
EI
approach
,
FF
×
W
f
,
approach
EI approach,SAF is nvPM emissions index in mg/kg of the gas turbine engine when operating at around 30% available thrust for the given operating conditions, or for other different operating conditions, when the fuel provided to the plurality of fuel spray nozzles comprises the sustainable aviation fuel;
EI approach,FF is nvPM emissions index in mg/kg of the gas turbine engine when operating at around 30% available thrust for the same operating conditions at which EI approach,SAF is calculated, when the fuel provided to the plurality of fuel spray nozzles is the fossil-based hydrocarbon fuel;
W f,approach is total mass flow rate of the fuel provided to the plurality of fuel spray nozzles in kg/s when the gas turbine engine is operating at around 30% available thrust for the same operating conditions at which EI approach,SAF and EI approach,FF are calculated; and
the controller is configured to control the fuel metering unit to control the fuel comprising the sustainable aviation fuel and provided to the plurality of fuel spray nozzles to achieve around 30% available thrust for the given operating conditions or the other different operating conditions;
the approach nvPM emissions index ratio-modified fuel flow rate is less than 0.4 kg/s.
8 . The gas turbine engine of claim 7 , wherein the approach nvPM emissions index ratio-modified fuel flow rate in kg/s is less than 0.343.
9 . The gas turbine engine of claim 7 , wherein the approach nvPM emissions index ratio-modified fuel flow rate in kg/s is less than or equal to 0.0526.
10 . The gas turbine engine of claim 1 , wherein:
an idle nvPM emissions index ratio-modified fuel flow rate is defined as:
EI
idle
,
SAF
EI
idle
,
FF
×
W
f
,
idle
EI idle,SAF is nvPM emissions index in mg/kg of the gas turbine engine when operating at around 7% available thrust for the given operating conditions, or for other different operating conditions, when the fuel provided to the plurality of fuel spray nozzles comprises the sustainable aviation fuel;
EI idle,FF is nvPM emissions index in mg/kg of the gas turbine engine when operating at around 7% available thrust for the same operating conditions at which EI idle,SAF is calculated, when the fuel provided to the plurality of fuel spray nozzles is the fossil-based hydrocarbon fuel;
W f,idle is total mass flow rate of the fuel provided to the plurality of fuel spray nozzles in kg/s when the gas turbine engine is operating at around 7% available thrust for the same operating conditions at which EI idle,SAF and EI idle,FF are calculated; and
the controller is configured to control the fuel metering unit to control the fuel comprising the sustainable aviation fuel and provided to the plurality of fuel spray nozzles to achieve around 7% available thrust for the given operating conditions or the other different operating conditions;
the idle nvPM emissions index ratio-modified fuel flow rate is less than 0.2 kg/s.
11 . The gas turbine engine of claim 10 , wherein the idle nvPM emissions index ratio-modified fuel flow rate in kg/s is less than 0.118.
12 . The gas turbine engine of claim 10 , wherein the idle nvPM emissions index ratio-modified fuel flow rate in kg/s is less than or equal to 0.0113.
13 . The gas turbine engine of claim 1 , wherein
the ratio of the number of the fuel spray nozzles of the first subset of fuel spray nozzles to the number of the fuel spray nozzles of the second subset of fuel spray nozzles is in a range of 1:3 to 1:4; and/or
wherein the number of the fuel spray nozzles of the first subset of fuel spray nozzles is between 1 and 10, and the number of the fuel spray nozzles of the second subset of fuel spray nozzles is between 10 and 25.
14 . The gas turbine engine of claim 1 , wherein
the combustor comprises ignitors; and
each fuel spray nozzle of the first subset of fuel spray nozzles is located nearer a respective ignitor of the ignitors than each fuel spray nozzle of the second subset of the fuel spray nozzles, and/or one or more of the ignitors is arranged diametrically opposite another one or more of the ignitors.
15 . The gas turbine engine of claim 1 , wherein the fuel provided to the plurality of fuel spray nozzles comprises the sustainable aviation fuel with a percentage from 50% to 100%.
16 . A method of operating a gas turbine engine, the gas turbine engine comprising:
a fuel distribution system comprising a controller and a fuel metering unit; and
a combustor comprising a combustion chamber and a plurality of fuel spray nozzles, wherein the plurality of fuel spray nozzles are configured to inject fuel into the combustion chamber with a total mass flow rate controlled by the fuel metering unit,
the plurality of fuel spray nozzles comprises a first subset of fuel spray nozzles and a second subset of fuel spray nozzles,
the combustor is operable so that each fuel spray nozzle of the first subset of fuel spray nozzles is supplied with a first portion of the fuel at a first mass flow rate,
each fuel spray nozzle of the second subset of fuel spray nozzles is supplied with a second portion of the fuel at a second mass flow rate, and the first mass flow rate is greater than the second mass flow rate,
a ratio of a number of the fuel spray nozzles of the first subset of fuel spray nozzles to a number of the fuel spray nozzles of the second subset of fuel spray nozzles is in a range of 1:2 to 1:5;
maximum take-off (MTO) non-volatile particulate matter (nvPM) emissions index ratio-modified fuel flow rate in kg/s is defined as:
EI
maxTO
,
SAF
EI
maxTO
,
FF
×
W
f
,
maxTO
EI maxTO,SAF is nvPM emissions index in mg/kg of the gas turbine engine when operating at around 100% available thrust for given operating conditions, when the fuel provided to the plurality of fuel spray nozzles comprises a sustainable aviation fuel;
EI maxTO,FF is nvPM emissions index in mg/kg of the gas turbine engine when operating at around 100% available thrust for the given operating conditions, when the fuel provided to the plurality of fuel spray nozzles is a fossil-based hydrocarbon fuel; and
W f,maxTO is a total mass flow rate in kg/s of the fuel provided to the plurality of fuel spray nozzles when the gas turbine engine is operating at around 100% available thrust for the given operating conditions;
the method further comprising using the fuel metering unit to control the fuel comprising the sustainable aviation fuel and provided to the plurality of fuel spray nozzles to achieve around 100% available thrust for the given operating conditions and the MTO nvPM emissions index ratio-modified fuel flow rate is less than 2 kg/s.
17 . The method of claim 16 , wherein:
a climb nvPM emissions index ratio-modified fuel flow rate is defined as:
EI
climb
,
SAF
EI
climb
,
FF
×
W
f
,
climb
EI climb,SAF is nvPM emissions index in mg/kg of the gas turbine engine when operating at around 85% available thrust for the given operating conditions, or for other different operating conditions, when the fuel provided to the plurality of fuel spray nozzles comprises the sustainable aviation fuel;
EI climb,FF is nvPM emissions index in mg/kg of the gas turbine engine when operating at around 85% available thrust for the same operating conditions at which EI climb,SAF is calculated, when the fuel provided to the plurality of fuel spray nozzles is the fossil-based hydrocarbon fuel;
W f,climb is total mass flow rate of the fuel provided to the plurality of fuel spray nozzles in kg/s when the gas turbine engine is operating at around 85% available thrust for the same operating conditions at which EI climb,SAF and EI climb,FF are calculated; and
the method further comprising using the fuel metering unit to control the fuel comprising the sustainable aviation fuel and provided to the plurality of fuel spray nozzles to achieve around 85% available thrust for the given operating conditions or the other different operating conditions and the climb nvPM emissions index ratio-modified fuel flow rate is less than 2 kg/s.
18 . The method of claim 16 , wherein:
an approach nvPM emissions index ratio-modified fuel flow rate is defined as:
EI
approach
,
SAF
EI
approach
,
FF
×
W
f
,
approach
EI approach,SAF is nvPM emissions index in mg/kg of the gas turbine engine when operating at around 30% available thrust for the given operating conditions, or for other different operating conditions, when the fuel provided to the plurality of fuel spray nozzles comprises the sustainable aviation fuel; and
EI approach,FF is nvPM emissions index in mg/kg of the gas turbine engine when operating at around 30% available thrust for the same operating conditions at which EI approach,SAF is calculated, when the fuel provided to the plurality of fuel spray nozzles is the fossil-based hydrocarbon fuel;
W f,approach is total mass flow rate of the fuel provided to the plurality of fuel spray nozzles in kg/s when the gas turbine engine is operating at round 30% available thrust for the same operating conditions at which EI approach,SAF and EI approach,FF are calculated; and
the method further comprising using the fuel metering unit to control the fuel comprising the sustainable aviation fuel and provided to the plurality of fuel spray nozzles to achieve around 30% available thrust for the given operating conditions or the other different operating conditions and the approach nvPM emissions index ratio-modified fuel flow rate is less than 0.4 kg/s.
19 . The method of claim 16 , wherein:
an idle nvPM emissions index ratio-modified fuel flow rate is defined as:
EI
idle
,
SAF
EI
idle
,
FF
×
W
f
,
idle
EI idle,SAF is nvPM emissions index in mg/kg of the gas turbine engine when operating at around 7% available thrust for the given operating conditions, or for other different operating conditions, when the fuel provided to the plurality of fuel spray nozzles comprises the sustainable aviation fuel;
EI idle,FF is nvPM emissions index in mg/kg of the gas turbine engine when operating at around 7% available thrust for the same operating conditions at which EI idle,SAF is calculated, when the fuel provided to the plurality of fuel spray nozzles is the fossil-based hydrocarbon fuel;
W f,idle is total mass flow rate of the fuel provided to the plurality of fuel spray nozzles in kg/s when the gas turbine engine is operating at around 7% available thrust for the same operating conditions at which EI idle,SAF and EI idle,FF are calculated; and
the method further comprising using the fuel metering unit to control the fuel comprising the sustainable aviation fuel and provided to the plurality of fuel spray nozzles to achieve around 7% available thrust for the given operating conditions or other different operating conditions and the idle nvPM emissions index ratio-modified fuel flow rate is less than 0.2 kg/s.