Piston thermal analysis

[gio1]

Hello,

I am planning a FE structural analysis of a piston for a IC engine. A preliminary thermal analysis (by FEA too) is needed to calculate the temperature field (responsible for a great deal of the stresses)

The boundary conditions required for the thermal analysis are: gas temperature and Heat transfer coefficents at the piston/fluid interfaces. The underside of the piston is cooled by an oil jet, so an HTC is needed for that area as well.

Has anybody got an idea or established methodology on how to estimate these values, possibly locally?

It is important that the temperature distribution is as accurate as possible to be able to predict realistic stresses!

Thanks

Gio1

 

[ivymike]

Usually that sort of information is proprietary and comes from "experience-based" databases (empirical). Check out SAE 931139 for related info.

 

[enginesrus]

Or you have to run tests, with appropriate instrumentation.
To establish the parameters. Many many variables exist.

 

[gio1]

I have access to some performance simulation software to evaluate fuelling, pressure, heat flux (total value), but what about HTC around the piston?

 

[kmpillai]

Dear gio1,
As you mentioned that you are having a simulation software. I hope it will give the presuure and temperature of the cylinder contents with respect to crank angle during a cycle. From this data, their are number of correlations are available to calculate the heat transfer coefficient. Out of which one corellation given by Woschni is widely used by various people. Please refer the SAE paper No: 670931 for the correlation.

Regards,
KMPillai

 

[TKengine]

Latelly I have seen that Filipi published an interesting dynamic model but I am not able to tell more in the moment, I am not in my office where I have their paper. Try with search engine I think it is not so wide area you can find it.