Evaluation of a Particulate Sampling Methodology From a Gas Turbine Exhaust Using Real-Time Size and Number Analysis at Simulated Aircraft Conditions

Two differential mobility spectrometers (DMS 500) were used to measure particulate size distributions and particulate matter losses in the exhaust of a simulated gas turbine combustor test rig. The rig is a stable gas turbine combustor simulator providing particles of physicochemical properties analogous to real aircraft engines. The rig ran at three operating conditions, giving a range of organic to elemental carbon distributions, allowing different aerosol compositions to be formed for comparison and analysis of transport losses. Smoke number from a recognised filter stain method and gas analysis of the exhaust were also taken to prove representative engine conditions. The two instruments were separated by 10m of heated stainless steel sample line and a range of transitional to turbulent flow rates from 19L/min to 64L/min were utilised for the comparative analysis. The aerosols showed measureable transport losses dependant on organic fraction, while flow rate showed substantial effects dependent on the flow state within the line. Comparisons made to the particle transport loss model from United Technologies Research Center show agreement in trend losses relative to size distribution of the particulate matter, but with losses being higher than predicted.