Internal combustion engine deck inputting format

[mizu0fire0]

hello , how does aviary process internal combustion engines given that the required variables by Aviary do not include engine power but instead a thrust which is more conventional for gas turbin engines .

[jkirk5]

In general, we intend for EngineModels to be complete packages of everything needed in a propulsion system to turn energy into thrust - but this isn't actually required! I'm assuming you are trying to use an EngineDeck with data representing your turboshaft or piston engine since there is a required variables check that happens there. By default EngineDecks assume you are modeling a turbofan engine (so it checks that you provided thrust in your data table), but you can provide your own list of required variables your particular model needs like so:

from aviary.propulsion.utils import EngineModelVariables as vars
from aviary.propulsion.engine_deck import EngineDeck

required_vars = {vars.MACH, vars.ALTITUDE, vars.THROTTLE, vars.SHAFT_POWER}
example_engine = EngineDeck('name', required_variables=required_vars)

Or you could just set required_vars to an empty set {} if you don't want Aviary to double-check your data tables at all. There's nothing particularly special about the variables in EngineModelVariables other than calling out variables that Aviary knows to collect and sum to aircraft-level totals if they are available from your engines.

If you're modeling a propeller aircraft, you'll want to check out the TurbopropModel ([here] https://github.com/OpenMDAO/Aviary/blob/main/aviary/subsystems/propulsion/turboprop_model.py)). Despite the name, the TurbopropModel is pretty generic and is just a way to connect together a shaft power generating device, a gearbox, and a propeller, and the models used can be easily swapped out. I have documentation on how to use that model coming soon (#689) - it's not in the code yet but feel free to take a sneak peak. That update will overhaul a lot of the propulsion docs in general, they are currently pretty stale and are missing a lot of important information on creating your own models.

[mizu0fire0]

@jkirk5 assuming that i am inputting a propeller map and an engine performance deck externally and not modeling it within aviary , would the EngineDeck script need to be modified or used at all ?