Successful Completion of SAMPLE II Scaled Testing

?Studying, sampling and measuring of aircraft particulate emissions II (SAMPLE II)?

The global effects of aircraft Particulate Matter (PM) emissions are a key concern from the point of human health and climate change. Controls on aircraft emissions and maintaining compliance for local air quality standards at European airports is currently an important issue and expected to be so for future generations. Whilst significant effort is being made to identify, quantify, model and predict these effects there is still a sizeable amount of development work required to produce a working specification for the absolute measurement of quantity of PM. One of the measurement metrics important for human health impact is known to be active surface area. However, commercially available instrumentation is still under development for this metric. Mass, size and number concentration are the typical metrics used for particle characterisation and are also of significant importance. Any measurement technique used in the future will need to be measured in a format that can act as a standardised test under engine certification conditions. Other known problems include the accurate on-site quantification of volatile and non-volatile PM emissions.

EASA funded a 1 year study (known as the SAMPLE project), commencing in December 2008, which along with APEX measurements made in the United States,? was one of the first collaborative programmes designed to evaluate the nature of PM, whilst assessing the applicability of a number of modern measurement techniques. Conclusions from the SAMPLE I programme (Petzold and Marsh, 2009) suggested that calibration of the measurement techniques is critical, the effects of the sampling system on the PM in the sample need to be fully understood, further analysis of volatile species is required and that a subsequent phase of testing should involve a full modern gas turbine test.

The objectives of this proposed SAMPLE II project are therefore:

To undertake a review of potential calibration sources for aircraft PM monitoring hardware.
To construct and characterise an exhaust sample transport system to systematically capture emissions from gas turbine exhausts. Development will also involve consideration of how to minimise the transformation of the sample as it moves through the system.
To employ a carefully controlled dilution system, analysing the differences of probe tip vs. downstream dilution, active probe tip water cooling and diluent temperature in order to minimise changes in sample dilution due to changes in analyser demands.
Make measurements using commercial state-of-the art particulate mass and number instrumentation described in AIR6037 and directly compare to standard ICAO smoke number instrumentation.
Improve the methodologies, techniques and understanding of volatile particulate matter in the plume of gas turbine exhausts using commercially available technology.
Rig testing, making use of a combustor and turbine simulator, combined with engine testing under certification conditions.
Assessment of PM mass and number replacing SN with respect to the current visibility criterion.