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Measurement of Gaseous HAP Emissions from Idling Aircraft as a Function of Engine and Ambient Conditions (2012) / Chapter Skim
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Pages 9-13

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From page 9...
... After examining the data tabulated in Appendix A and the detailed engine data recorded in the data recorder, fuel flow seems to best collapse the observed variability in emission indices for the speciated VOCs of interest. Several HAP compounds were quantified in this study and tended to exhibit highly correlated behavior, as will be shown later.
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From page 10...
... Figure III-3 presents all measured formaldehyde emission indices, from every test conducted when the ambient air was lower than 0°C in 2009 and 2010 at MDW, plotted versus fuel flow for 11 different CFM56-7B24 combustors. Of all parameters recorded in the digital flight data records, fuel flow best linearizes the trend in emission index.
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From page 11...
... This procedure will be used to account for the engine-to-engine variability observed in absolute UHC emission indices for the on-wing engine tests in order to draw out whatever trend may exist in the UHC emission index with fuel flow. This procedure is also used to directly examine any systematic coupling between fuel flow and specific VOC emission indices.
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From page 12...
... . The measured VOC/fuel flow dependence compares favorably with that determined for the UHC emission indices derived from the ICAO databank of -54±4 (s kg-1)
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From page 13...
... This has been estimated by combining the overall systematic uncertainty in the measurements of emission index with the average spread observed in the fuel flow dependence parameter for formaldehyde and ethene. The overall spread, however, of observed variability in this parameter when considering the entire distribution of VOCs measured in this study is large (see Figure III-6)
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Key Terms

  • test conducted
  • engine state
  • emission index
  • standard error
  • fuel flow

  • engine test
  • ambient temperature
  • icao databank
  • engine exhaust
  • flow rate

  • emission indices
  • voc emissions
  • speciated voc
  • test result
  • hap emissions

  • data record
  • combustor design


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