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Tobias Weckenmann authoredTobias Weckenmann authored
engine
Library in UNICADO
The The _engine_
library serves as the core analysis tool for engine data within UNICADO. It provides access to all possible engine data for every tool in UNICADO. The data can be fixed for an engine or at a given operating point. The data output depends on various factors such as the scale factor and power and bleed offtakes from the engine. The primary objective is to establish a single source of truth for engine data retrieval.
propulsionDesign
Role in Within the propulsionDesign
module:
- Engines for the aircraft are selected, and their respective files are copied to the engine directory.
- The scale factor is calculated, determining how the engine's thrust is adjusted to meet aircraft requirements (refer to the
propulsionDesign
documentation).
The engine
library applies this scale factor, ensuring that aircraft parameters can be accessed without further manual adjustments.
Engine Data Formats
The engine data is stored in:
-
engine.xml
— Contains data independent of the operating point. -
CSV files — Store values dependent on:
- Mach number
- Altitude
- Engine power setting
Note: The data in these files is raw and unscaled. The only modification made in
propulsionDesign
is to the fuel flow CSV file, reflecting user-defined efficiency improvements.
engine
Library
Functionality of the The library is responsible for:
- Reading engine data
- Applying scaling factors to the data
- Modifying values based on performance-influencing factors like bleed and power offtakes
Factors Affecting Engine Performance
The engine
library incorporates the following factors, either by default or as optional parameters:
-
Scale factor from
propulsionDesign
- Temperature variations (non-ISA standard conditions)
- Engine derating
- Bleed air extraction (for turbofan engines)
- Spool shaft offtake (for turbofan engines)
How the Library Retrieves Data
-
If data is not dependent on the operating point → Uses
engine.xml
in a simple readout. -
If data is dependent on the operating point → Uses CSV files and requires:
- Mach number
- Altitude
- Engine power setting (e.g., N1 for turbofan engines)
A linear interpolation is performed between existing operating points in the deck when retrieving values from CSV files.