Atmospheric Environment, vol.116, pp.102-111, 2015 (SCI-Expanded)
© 2015 Elsevier Ltd.This study presents an analysis of the seventeen complete measurements of gaseous emissions of eleven different CFM56-7B26 turbofan engines during the regular test-cell runs. A novel measurement setup is established in which the sample probe is located immediately behind the low pressure turbine rotor. Recording a total of 49,190 data points for 26 raw variables (obtained from both the emission measurement and engine test systems), emissions are characterized with stable engine power settings representing main flight phases, as well as fuel flow of the engine during the entire run. Carbon monoxide and total hydrocarbons concentrations are found to be a strong function of fuel flow at low power settings, and nitrogen oxides emissions at high power settings. In comparison to emission indices provided by the International Civil Aviation Organization, the current study results in considerably higher carbon monoxide and hydrocarbons under idle conditions, with relatively lower nitrogen oxides at almost all of the power settings. On the other hand, significant differences in levels of nitrogen oxides are observed from one engine test to another, emphasizing the effects of the engine and the ambient air conditions. The average NO