OpenWAM » Ethanol fuel mix, case setup and injection type

Ethanol fuel mix, case setup and injection type

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  • March 6, 2017 at 10:09 pm #762
    David VidalDavid Vidal
    Participant

    Hi,

    First of  all I would like to thank the CMT for sharing with us OpenWam. I really think is a very useful tool.

    Currently I am trying to model a spark ignition engine that is going to run on an mixture of ethanol and gasoline. My first question is the following:

    Does openwan allow to generate alternative fuel mixtures different from “diesel” and “gasoline”?

    My second question is related with how to set up different running cases. I would like to know if it i possible to set cases to run automatically one after the other. Like running steady state analysis from 1000rpm to 6000rpm in 500rmp increments?

    Is openwan giving the possibility of  to run optimization studies?

    And the last question is if it is possible to differentiate between direct and port fuel injection engines in openwam.

    I would appreciate you help on thi matter.

     

    Kind regards,

    David

    March 7, 2017 at 3:47 pm #763
    F. J. ArnauArnau F. J.
    Keymaster

    In this moment, openwam is not able to run with ethanol. It is ready for diesel. Even gasoline could provide wrong results.
    To generate different cases you need create different files for each case where you have to change some parameters not only the speed (fuel mass, initial pressure and temperatures…)

    March 7, 2017 at 4:13 pm #764
    David VidalDavid Vidal
    Participant

    Hi Arnau,

    Thanks a lot for you answer. I really appreciate it.

    Excuse my lack of expertise on 1D modelling. But would it be possible to model the combustion of my specific fuel mixture (gasoline+ethanol) imposing the burn rates?

    Regarding the injection type. I guess that openwam just copes with direct injection?

    For running different cases, do you mean I would need to run different simulation files? It is not possible of having different cases in the same openwam simulation file?

    Cheers

     

    March 7, 2017 at 4:27 pm #765
    David VidalDavid Vidal
    Participant

    Sorry,

    But I think I did not specify what the simulation is going to be for.

    The things I would like to do are engine performance related simulations like changing cam timing, intake and exhaust tuning lengths, plenum volumes and so on… And see the power and torque figures I can get..

    I am not trying to predict combustion behaviour or similar things.

    Cheers

    March 8, 2017 at 7:38 am #766
    F. J. ArnauArnau F. J.
    Keymaster

    The best option to simulate the combustion is to provide the heat release rate. You can use a combination of 4 Wiebe function to fit the real heat release rate. As I said, in this moment is not possible to have different cases in the same file.
    Openwam is a good tool to predict the effect of geometry or valve timing in volumetric efficiency, but it is not able to predict the effect of these changes in combustion.

    March 8, 2017 at 8:45 am #767
    David VidalDavid Vidal
    Participant

    Good morning Arnau,

    Thanks for that.

    Do you think that if I impose the heat release of my fuel mixture using the “gasoline” option as s fuel the model could work?

    When you say that the model is not able to predict the effect of geometry changes on engine combustion, do you mean that if i.e I change the plenum volume or the exhaust length I could see the effect in the volumetric efficiency but the new  possible torque and power values would not be reliable?

    March 21, 2017 at 6:17 pm #768
    F. J. ArnauArnau F. J.
    Keymaster

    Using wiebe functions you are imposing the combustion. If you modify any parameter in the engine that can affect the combustion, the model won’t predict this change in combustion process.

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