Predictive model for jet engine test cell opacity

Abstract

A mathematical model was developed to predict the plume opacity of jet engine test cells (it assumes that the cause of the plume visibility, i.e. opacity, is carbon particles). The data input required for the model includes: the particle density, concentration, and size distribution in the exhaust gas, and the effective stack diameter. Previous data obtained for J‐57 engines were used to test the model, and the difference between the theoretical and measured transmittance was generally within one percent. The model also predicts the theoretical effect of using a venturi scrubber to treat the exhaust emissions. These predictions indicate that even at the limits of operability, a scrubber would only achieve a minimal effect on the observed visibility.