Emissions of non-volatile particulate matter from gas turbine engines combusting sustainable aviation fuel and fossil-based hydrocarbon fuel
A gas turbine engine includes: a rich burn, quick quench, lean burn combustor having a number of fuel spray nozzles in the range of 14-22 or a number of fuel spray nozzles per unit engine core size in the range 2 to 6. An MTO nvPM emissions index ratio is defined as: EI max TO , SAF EI max TO , FF where: EI maxTO,SAF and EI maxTO,FF are respectively the nvPM emissions index in mg/kg of the gas turbine engine when operating at around 100% available thrust for the given operating conditions if a fuel provided to the fuel spray nozzles includes a sustainable aviation fuel (SAF) or is a fossil-based hydrocarbon fuel. The MTO nvPM emissions index ratio of the gas turbine engine is less than 1. The gas turbine engine is configured to provide fuel including a SAF to the fuel spray nozzles. Also disclosed is a method of operating a gas turbine engine.
1 . A gas turbine engine for an aircraft, comprising:
a rich burn, quick quench, lean burn (RQL) combustor having a number of fuel spray nozzles in the range of 14-22 or a number of fuel spray nozzles per unit engine core size in the range 2 to 6 where engine core size is defined, at a top of climb operating condition, as:
Core
size
=
m
.
2
T
3
P
3
,
where {dot over (m)} 2 =mass flow rate, in lbs per second, of air on entry to a high-pressure compressor, T 3 =temperature, in Kelvin, of air on exit from the high-pressure compressor, and P 3 =pressure, in lb inches per second squared per inch squared, of air on exit from the high-pressure compressor such that a unit of core size is expressed as:
s
·
K
1
2
·
in
;
and
wherein:
an MTO nvPM emissions index ratio is defined as:
EI
maxTO
,
SAF
EI
maxTO
,
FF
where:
EI maxTO,SAF is the nvPM emissions index in mg/kg of the gas turbine engine when operating at around 100% available thrust for given operating conditions if a fuel provided to the fuel spray nozzles comprises a sustainable aviation fuel (SAF); and
EI maxTO,FF is the nvPM emissions index in mg/kg of the gas turbine engine when operating at around 100% available thrust for the given operating conditions if a fuel provided to the fuel spray nozzles is a fossil-based hydrocarbon fuel;
the MTO nvPM emissions index ratio of the gas turbine engine is less than 1; and
the gas turbine engine is configured to provide fuel comprising a SAF to the fuel spray nozzles, wherein
the fuel spray nozzles comprises one or more duplex nozzles and one or more single flow nozzles; and
the combustor comprises one or more ignitors each arranged adjacent to one or more of the duplex nozzles, and/or wherein the number of fuel spray nozzles per unit engine core size is in the range 2.5 to 4.5.
2 . The gas turbine engine of claim 1 , wherein the MTO nvPM emissions index ratio is less than or equal to 0.93.
3 . The gas turbine engine of claim 1 , wherein the MTO nvPM emissions index ratio is greater than or equal to 0.15.
4 . The gas turbine engine of claim 1 , wherein a climb nvPM emissions index ratio is defined as:
EI
climb
,
SAF
EI
climb
,
FF
where:
EI climb ,SAF is the 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 different given operating conditions, if a fuel provided to the fuel spray nozzles comprises a sustainable aviation fuel (SAF); and
EI climb,FF is the nvPM emissions index in mg/kg of the gas turbine engine when operating at around 85% available thrust for the same given operating conditions at which EI climb,SAF is calculated and if a fuel provided to the fuel spray nozzles is a fossil-based hydrocarbon fuel;
and wherein the climb nvPM emissions index ratio of the gas turbine engine is less than 1.
5 . The gas turbine engine of claim 4 , wherein the climb nvPM emissions index ratio is less than or equal to 0.9.
6 . The gas turbine engine of claim 4 , wherein the climb nvPM emissions index ratio is greater than or equal to 0.1.
7 . The gas turbine engine of claim 1 , wherein an approach nvPM emissions index ratio is defined as:
EI
approach
,
SAF
EI
approach
,
FF
where:
EI approach,SAF is the 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 different given operating conditions, if a fuel provided to the fuel spray nozzles comprises a sustainable aviation fuel (SAF); and
EI approach,FF is the nvPM emissions index in mg/kg of the gas turbine engine when operating at around 30% available thrust for the same given operating conditions at which EI approach,SAF is calculated and if a fuel provided to the fuel spray nozzles is a fossil-based hydrocarbon fuel;
and wherein the approach nvPM emissions index ratio of the gas turbine engine is less than 1.
8 . The gas turbine engine of claim 7 , wherein the approach nvPM emissions index ratio is less than or equal to 0.8.
9 . The gas turbine engine of claim 7 , wherein the approach nvPM emissions index ratio is greater than or equal to 0.03.
10 . The gas turbine engine of claim 1 , wherein an idle nvPM emissions index ratio is defined as:
EI
idle
,
SAF
EI
idle
,
FF
where:
EI idle,SAF is the 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 different given operating conditions, and if a fuel provided to the fuel spray nozzles comprises a sustainable aviation fuel (SAF); and
EI idle,FF is the nvPM emissions index in mg/kg of the gas turbine engine when 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 fuel spray nozzles is a fossil-based hydrocarbon fuel;
and wherein the idle nvPM emissions index ratio of the gas turbine engine is less than 1.
11 . The gas turbine engine of claim 10 , wherein the idle nvPM emissions index ratio is less than or equal to 0.8.
12 . The gas turbine engine of claim 10 , wherein the idle nvPM emissions index ratio is greater than or equal to 0.02.
13 . The gas turbine engine of claim 1 , wherein the fuel provided to the fuel spray nozzles comprises a % SAF in the range of 50% to 100%.
14 . A method of operating the gas turbine engine of claim 1 , the method comprising providing fuel comprising a sustainable aviation fuel to the fuel spray nozzles.
15 . The gas turbine engine of claim 1 , wherein the top of climb occurs at 30,000 to 39,000 feet, a forward speed of Mach Number 0.75 to 0.85, and ambient air temperature of ISA+10K to ISA+15K.
16 . The gas turbine engine of claim 15 , wherein the top of climb occurs at 35,000 feet.
17 . A method of operating a gas turbine engine, the gas turbine engine comprising:
a rich burn, quick quench, lean burn (RQL) combustor having a number of fuel spray nozzles in the range of 14-22 or a number of fuel spray nozzles per unit engine core size in the range 2 to 6 where engine core size is defined, at a top of climb operating condition, as:
Core
size
=
m
.
2
T
3
P
3
,
where {dot over (m)} 2 =mass flow rate, in lbs per second, of air on entry to a high-pressure compressor, T 3 =temperature, in Kelvin, of air on exit from the high-pressure compressor, and P 3 =pressure, in lb inches per second squared per inch squared, of air on exit from the high-pressure compressor such that a unit of core size is expressed as:
s
·
K
1
2
·
in
;
and
wherein an MTO nvPM emissions index ratio is defined as:
EI
maxTO
,
SAF
EI
maxTO
,
FF
where:
EI maxTO,SAF is the nvPM emissions index in mg/kg of the gas turbine engine when operating at around 100% available thrust for given operating conditions if a fuel provided to the fuel spray nozzles comprises a sustainable aviation fuel (SAF); and
EI maxTO,FF is the nvPM emissions index in mg/kg of the gas turbine engine when operating at around 100% available thrust for the given operating conditions if a fuel provided to the fuel spray nozzles is a fossil-based hydrocarbon fuel;
the MTO nvPM emissions index ratio of the gas turbine engine is less than 1;
the gas turbine engine is configured to provide fuel comprising a SAF to the fuel spray nozzles;
the fuel spray nozzles comprises one or more duplex nozzles and one or more single flow nozzles; and
the combustor comprises one or more ignitors each arranged adjacent to one or more of the duplex nozzles, and/or wherein the number of fuel spray nozzles per unit engine core size is in the range 2.5 to 4.5; wherein
the method comprises providing fuel comprising a sustainable aviation fuel to the fuel spray nozzles.
18 . The method of claim 17 , wherein a climb nvPM emissions index ratio is defined as:
EI
climb
,
SAF
EI
climb
,
FF
where:
EI climb ,SAF is the 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 different given operating conditions, if a fuel provided to the fuel spray nozzles comprises a sustainable aviation fuel (SAF); and
EI climb,FF is the nvPM emissions index in mg/kg of the gas turbine engine when operating at around 85% available thrust for the same given operating conditions at which EI climb,SAF is calculated and if a fuel provided to the fuel spray nozzles is a fossil-based hydrocarbon fuel;
and wherein the climb nvPM emissions index ratio of the gas turbine engine is less than 1.
19 . The method of claim 17 , wherein an approach nvPM emissions index ratio is defined as:
EI
approach
,
SAF
EI
approach
,
FF
where:
EI approach,SAF is the 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 different given operating conditions, if a fuel provided to the fuel spray nozzles comprises a sustainable aviation fuel (SAF); and
EI approach,FF is the nvPM emissions index in mg/kg of the gas turbine engine when operating at around 30% available thrust for the same given operating conditions at which EI approach,SAF is calculated and if a fuel provided to the fuel spray nozzles is a fossil-based hydrocarbon fuel;
and wherein the approach nvPM emissions index ratio of the gas turbine engine is less than 1.
20 . The method of claim 17 , wherein an idle nvPM emissions index ratio is defined as:
EI
idle
,
SAF
EI
idle
,
FF
where:
EI idle,SAF is the 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 different given operating conditions, and if a fuel provided to the fuel spray nozzles comprises a sustainable aviation fuel (SAF); and
EI idle,FF is the nvPM emissions index in mg/kg of the gas turbine engine when 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 fuel spray nozzles is a fossil-based hydrocarbon fuel;
and wherein the idle nvPM emissions index ratio of the gas turbine engine is less than 1.