Advanced Turbine Exhaust Particulate Measurement System

The presence of particulates in the exhaust plumes of gas turbine engines has significant implications for naval aviation. First, it is known that the plume visibility of jet aircraft is the result of the existence of such particles in the exhaust plume. The quantitative prediction of this plume visibility, and its effect on combat survivability, as well as the modification of the visibility, requires accurate knowledge of the particulate size distribution function and number density in the exhaust plume. Second, the particulate effluent of gas turbine engine testing facilities and jet aircraft represent pollution sources that requires quantifiable and potential modification. Again, the particulate size distribution function and number density are required. Currently, the ability to measure these parameters is limited to the use of extraction probes which suffer from sampling efforts, is time-consuming, and is, therefore, expensive in its operation. The proposed work recommends the development of an optical, in situ technique that requires no sample collection and is rapid in its operation. The tasks of the proposed work include the determination of the accuracy of the method and the performance of an initial field test.