Envisa Projects - Turbogas - Advanced Turbofan Engine Emissions Model

Turbogas is an advanced turbofan engine emissions model. It performs precise estimates of the quantities of NOX, CO2, water and contrails’ lifetime generated by an aircraft along a very fine trajectory (up to 1 point per second or less) using ambient conditions at every point.

Turbogas has been validated thoroughly using data from measurements at airports and in flight.

Various methods are deployed in Turbogas in order to cover a wide range of situations with regard to data availability:

The default method implemented is the Boeing Fuel Flow Method 2 (BFFM2) which can be applied to most turbofan engines using publicly available data (ICAO Engine Exhaust Emissions Databank) (accuracy as per validation exercise: 10%).

The advanced method P3T3 based on compressor’s temperature, pressure, fuel-air-ratio and NOX emission index at four engine settings is also deployed in the tool – however, no default data is provided, such data must be provided and formatted by the Turbogas user (accuracy as per validation exercise: < 5%).

An innovative methodology based on estimates of T3 only (based on a paper by Tsague) has also been implemented within Turbogas. While the results from the validation performed showed some issues with accuracy for certain scenarios (±20-30%) it remains available as a last resort for engines not covered in existing databases.

For more information: turbogas.org