Engine modelling
 

Wondering if anybody can give me some advice on a two-stroke engine modelling.

I am new in STAR-CD and previously using Fluent.

I have recently converted an old mesh of STAR-CD 3 to STAR-CD 4 and working on it now. The next step I need to do is to define the undesteady boundary condition to the transfer port and exhaust port, and to define the motion of the cylinder and valve.

STAR-CD does seem quite different with Fluent. I will appreciate if anybody can give me some hints to save me some learning time.

Thank you.

Re: Engine modelling
 

Tutorial 13 will give you an idea how the moving grid and attachment boundary stuff works.

You can add unsteady boundary conditions either with tables or user subroutines.

Did you try the problem in Fluent?

Re: Engine modelling
 

I use Fluent to model the rotation of a propeller without unsteady boundary condition. For engine model, I have never tried in Fluent.

Thank you for your advice.

Re: Engine modelling
 

Hi, I suggest yo to look also for Es-Ice, the add-on that cover the engine problems in Star-cd
Bye
Andrea

Re: Engine modelling
 

Hi, I use es-ice which can handle two stroke models. I wouldn't even attempt a moving mesh engine model without es-ice. It is extremely complicated

Re: Engine modelling
 

Thank you for the opinions about es-ice. It is really useful.

I have browsed through the product overview of es-ice in STAR CD. Es-ice maybe a good solution to reduce the complexity of setup.

However, I still need to stick at STAR CD before the approval of purchase.

Re: Engine modelling
 

Hi,

I tested the table to define the unsteady boundary condition. It works!

I tried the tutorial presenting two blunt objects moving in opposite direction. However, the tutorial is not a strict forward transferable solution to a reciprocating engince case.

I am still confused with a few things.

To model the reciprocating piston, should I use a sliding mesh method or cell layer removal and addition method? Should I define the piston movement using an event file? Anything else I need to define?

Thank you for giving me a great help on this.

Re: Engine modelling
 

Did you do the tutorial of a reciprocating engine? It shows what you need for piston motion.

Re: Engine modelling
 

For the STAR-CD 4, tutorial 13 is aeroacoustic analysis.

I didn't get the reciprocating engine tutorial in STAR-CD.

Re: Engine modelling
 

In version 3.26, the internal combustion engine is tutorial 13.

Be careful with version 4. Not all version 4 releases support cell addition/deletion. I just checked version 4.06 & it appears to support cell addition/deletion. See chapter 13 in the version 4.06 user guide. It shows the steps required for moving piston.

Re: Engine modelling
 

I found the subtopic from user guide STAR-CD 4.06. Thank you for your guidance.