Energy_Network

[Chan Yi]

Hi:

I'm completely new to SUAVE here and still in the process of familiarizing with the function. I'm currently working on the preliminary design of aircraft with the size similar to a A320.  I'm wondering if it is possible to simplify the energy net-work process by considering it like a black-box without having to build the complete net-work of the engine, since the goal is more based on the preliminary design/performance of the wings. From the tutorials it seems like the net-work is a must in oder to call the functions and perform the analysis.

I currently only know the top-level parameters about the engine and would have to make many assumptions regarding the pressure ratio and efficiencies... I would be great if I can manually input a thrust under a given condition and still able to perform the aerodynamic and stability analysis.

Thanks for your help,

Yi

[Emilio]

Hi Yi,

I would use the propulsor surrogate. You could almost make up data. Ignore the propulsion and fuel burn result. Or make it so the SFC is 0.

Remember GiGo still applies, so if you're expecting reasonable fuel burn you will not get that.

You can also do single point segments, there are some that don't require a network at all.

-Emilio

[Chan Yi]

Hi Emilio:

Thanks for your reply. I've tried both methods and they all ran successfully for stability analysis.

I'm currently would like to analyze the performance, which means building a correct propulsion surrogate model is rather important.

I first created a .csv file where all the information I got from the performance map is stored. The format is shown in the picture below. I calculated 'SFC' as 'm_dor_fuel (kg/hour)/Thrust' and 'Throttle' is calculated by dividing current state thrust by max. thrust. The performance converged with no error, however I got zero fuel burn in the end. I looked into 'propulsor_surrogate.py' and found the sfc output from sfc=sfc.surrogate.predict(cond) is zero and haven't figured out why. What might possibly be the cause if we assume the .csv input is reasonable?

Additionally, how should I set a sfc_anchor value? (Is there a specific definition to this value?)

Appreciate your help once again!

Regards,

Yi

[Emilio]

The surrogates are picky at times. Quick things to check first, the number of engines >0. Is the surrogate extrapolating out of your data?

SFC anchor values are used for scaling. If you were going to do an optimization and planned to resize the engine at each iteration you would use this parameter.