Exhaust gas emissions evaluation in the flight of a multirole fighter equipped with a F100-PW-229 turbine engine

Th the Internatio implementati them to the v defined as sta setting values Such a proce multirole fig characteristic evaluate the parameters re

Once the propulsion s linked to ex Subsequently from the airc is necessary t The vari fighter aircra its turbine en emissions in article make estimating th aircrafts in important iss a turbine eng flue gas gene

Method
The concept is aimed at o into propulsi exhaust stre According to and velocity indicators re intake and f total mass o (Fig. 3).Kn consumption the exhaust instantaneou fed to the eng The sum corresponds where: ṁ air -air mas ṁ f -fuel mas ṁ exh -exhaus    Considering the relative thrust force values (K/K n ) depending on a number of engine operation parameters and present in each operation phase, it is possible to present those values as a function of the relative value of engine speed (n 1 ).By linking each operation phase to values recorded during the flight, the authors were able to determine operation areas defined by thrust force as a function of engine speed (n 1 ).
Flight profiles can be described on the basis of the distribution of points corresponding to given phases.For the most part, points corresponding to the engine start-up and warming up phase are located in the area within K/K max = 40% and corresponding to the low-pressure stage speed n 1 /n 1 nom = 70%.A number of points from this particular phase are located outside the said areathey denote the verification of correct operation of exhaust nozzle opening controller.The identified operation area also contains a number of points assigned to the taxiing phase and partially to the landing phase.The latter can be divided into two stages.The first stage corresponds to the approach to land, whereby engine operation parameters stay in the range typical of actual flight (K/K max = 40-80%, n 1 /n 1 nom = = 70-80%).The other stage is landing, whereby engine parameters are lower (K/K max = 40%, n 1 /n 1 nom = 70%).A similar division can be proposed for the take-off phase.In the first stage, i.e. acceleration and take-off proper, one can identify an area corresponding to the range of K/K max = 100% and n 1 /n 1 nom = 96%.The other stage corresponds to the ascent after take-off (K/K max = = 80-90% and n 1 /n 1 nom = 85-90%).The example of relative thrust force and fan speed values during the take-off relates to a plane taking off with the afterburner off and with a small load.If a plane takes off fully loaded, the afterburner is usually off.The afterburner increases the engine's propulsion force by approximately 70%.The extra force comes mostly from the mass of fuel additionally combusted in the afterburner chamber, located downstream of the engine's turbine assembly.The energy generated from fuel delivered to the afterburner chamber increases the energy of exhaust gas ejected from the exhaust nozzle, and thus the overall thrust force.Simultaneously it needs to be emphasized that afterburner status does not affect engine speed parameters (n 1 and n 2 ).The flow of air through the engine corresponds to values occurring at maximum thrust obtained with the afterburner off.The range of engine operation the afterburner on covers relative force points in excess of K/K max = 105%.The largest operation area covers points from the flight phase (K/K max = 40-170% and n 1 /n 1 nom = 45-105% of the low pressure stage speed).It is evident that this phase contains diverse values of the relative thrust force as a function of engine speed (n 1 ).The above analysis shows that operation of a low dual flow jet engine fitted in a aircraft stays in the following ranges: n 1 /n nom = 38-105% and K/K max = 40-170%.
The above division relative thrust force values (K/K max ) as a function of relative engine (n 1 /n 1 nom ) made it possible to identify the ranges of operation phases.Relative thrust force values below K/K max = 40% and relative engine speed up to n 1 /n 1 nom = 70% usually correspond to engine start-up, warming up, taxiing and cooling.Most of the range of K/K max = 40-100% and n 1 /n 1 nom = 45-105% corresponds to take-off and flight, as well as to the approach to land stage of the landing phase.Points in the operation range of K/K max = 100-170% and n 1 /n 1 nom = 95-105% correspond to afterburner on situations: these points represent the take-off phase and the maximum engine operation parameters during special maneuvers.
The example distribution of the engine operating parameters, expressed as relative power lever setting values, as a function of the relative shaft speed values n 1 indicate the potential for different engine load values for the individual shaft speeds.Consequently, additional parameters must be used to determine the operating status of the engine.
Among the recorded flight parameters and engine performance parameters, the parameters closely related to the engine load are the speed of the exhaust gas generator shaft n 2 , the exhaust gas temperature before the turbine T 3 , and the fuel consumption G e .By comparing these values with each other and the value of exhaust gas temperature T 3 , you the load factor of engine W p can be established (2).
By substituting the example values for the minimum load n 2 = 10,064 rpm, T 3 = 666 K and maximum load n 2 = 13,590 rpm, T 3 = 1276 K the following equations were obtained:

15.11
(3) In this way a certain kind of inverse value is obtained, namely the minimum load factor is characterized by a large value and the maximum load factor by small.Additional information about the engine

K/K n [%] n 1 /n 1 nom [%]
Start-up and warming up Taxiing Take-off Flight Landing Taxiing and cooling load can be obtained taking into account the excess air ratio [4].The value of this parameter was determined on the basis of stationary assessment of the exhaust gas composition carried out for the analyzed engine performed at an engine dynamometer.These studies have shown the dependence of the excess air ratio value on the load [4].Its values are respectively λ p min = 8.5 at the smallest engine load and λ p max = 6.5 at the highest load.Values of the following parameters: engine load W p and air excess ratio λ, are characterized by similar relations relative to the engine load (5,6).

[-]
Consequently, the excess air excess ratio λ must be linked to the determined load factor of the engine W p .Hence the relation (7,8) was proposed as: . .

(8)
Taking into account the similarity in the obtained relationships, the mean value can be used for further calculations Z w-λ = 1.67 .
As a result, the following equation ( 9) can be established: - ( 9 ) This equation is complementary to the equation for the determination of the air mass flow using fuel consumption (10): Where the above equation takes the form (11): The obtained relation in equation ( 1) allows to determine the value of the emitted flue gas based on the operating parameters recorded by the onboard flight recorder using the equation (12).Using the listed equations, an analysis of the exhaust gas flow estimation of a multirole fighter aircraft turbine engine during a default flight was performed.
According to the presented set of equations, the values of the following operating parameters were used in the calculation: temperature before turbine T 3 , shaft speed of flue gas generator n 2 , and fuel consumption G e .The results are graphically presented in Figure 7. Parameter changes described as time functions show a notable similarity between the T 3 temperature characteristic and the shaft rotational speed of the flue gas generator n 2 .Changes in these parameters result from changes in the fuel consumption G e , as they are a consequence of fuel combustion in the engine combustion chamber.Depending on the combustion process resulting from the load of the engine, the airflow change characteristics G p is obtained.From the described relationship, it can be identified as the main factor determining the value of the exhaust gas stream flowing from the engine G exh .The changes of these parameters along with the h fly flight characteristics presented in the bottom graph, highlight the flight characteristics that are specific to multirole fighter aircraft.
Taking into account the 1 second time resolution of the recorded parameters, the individual values can be summed up during the entire recorded flight performed by the aircraft.As a result, it was reported that during a flight lasting 7368 seconds, that is 2 hours, 2 minutes and 48 seconds, the F100-PW-229 engine powered aircraft consumed 3297 kg of fuel, used 348,003 kg of air and generated 351,301 kg of exhaust.

Conclusions
The analysis of the interdependence of the recorded operating parameters was carried out to evaluate the possibility of determining the instantaneous value of the flue gas generated by the turbine engine when operating in high load parameters.The analysis showed that there are relationships between the parameters recorded by the flight recorder during the aircraft flight.The analysis has also shown that information derived from the engine emission characteristics is required in the form of an excess air ratio λ value, which is necessary to establish the relationship of the combustion process in the engine to its load.The emission characteristics of the engine in the form of harmful exhaust gas emissions concentration values will be used in the next steps to determine the instantaneous emission values of the pollutants during the aircraft flight.
The study presented in this article was performed within the statutory research (contract No. 05/52/DSPB/0244).

Fig. 6 .
Fig. 6.Analyzed parameters in the engine operation range, recorded during the flight.

Fig. 7 .
Fig. 7. Variable values of operating parameters as a function of time; Recorded parameters: T 3 , n 2 , G e , h fly ; calculated parameters: λ, G p , G exh .