Particle Sampling System Designed to Simulate Aging of Aircraft Exhaust Plumes

Emissions performance of military engines has taken on an increasingly prominent importance for the DoD in recent years. Military bases which lie in areas that are out of compliance with EPA regulations are required to participate in that state's plan to come into compliance and improve the regional air quality. Particle emissions from all sources have come under increasingly stringent regulations from the EPA, and volatile particle emissions are especially critical to understand because of their potential health effects. Traditional engine-exit plane measurements are not suitable for volatile particles because they form downstream of the aircraft as the exhaust plume mixes with ambient air and cools. The number and size of these volatile particles once deposited in the atmosphere is the relevant information for determining the impact on local air quality. The goal of this project is design a volatile particle sampling system that simulates the process of aircraft plume aging. Under this program, standard plume dilution profiles will be identified and a prototype sampling system that captures the salient aspects of this dilution process will be built. Initial feasibility tests of mixing and sulfate nucleation in the prototype will be performed and compared to numerical microphysics simulations.