Standard Measurement of Aircraft Gas Turbine Engine Exhaust Smoke

Abstract

A standard system (equipment and procedures) for measuring smoke emitted by aircraft turbine engines has been developed. It has been adopted by several Federal Government agencies. In this paper, the system is explained and its accuracy defined. An experimentally determined relationship between the system’s parameters and true smoke density (weight of solids per unit volume) is presented and theoretically examined. The definition of smoke plume visibility in terms of the system’s parameters is also developed. This work led to the conclusion that aircraft turbine engine exhaust smoke is composed of two groups of particles: the very small, which are primarily responsible for visible obscuration, and larger particles, which may constitute as much as half of the total by weight, but do not appreciably contribute to plume visibility.