Hi,

I'm currently using Mixsim v1.7.4 with Fluent v5.5.14. Anyone else who is using Mixsim as I've got loads of questions regarding Mixsim uses that I don't know who to ask it to.

Thanks

Try me!

I will be using Mixsim shortly. I am waiting for v2.0 to come out. It interfaces with Gambit 2.04 and Fluent 6.0 very well from what I heard.

Thank you very much for your responses. Have you tried changing a 3D grid (constructed by Mixsim) in Gambit i.e. to insert internal devices that Mixsim couldn't manufacture or refining the grid in certain areas? If you have, could you please tell me where you found the source of information to do that (website/tutorial samples, etc) so I can look 'em up. Thanks.

Well, here's the deal. The old way is to bring something from Mixsim through Fluent 4, backwards into Gambit 1.3 to refine or generate the quality meshing you desire.

I received info that Mixsim 2.0 is coming out in two weeks. They said this version generates Gambit 2.0 database (.dbs) files and Fluent 6.0 case (.cas) files. It "should" be easy to interact among these programs. It's at least my hope that it will be easy. I just want to use Mixsim for the impeller geometries, but actually do the meshing and simulations in Gambit and Fluent.

-Eric R.

TQ. Yes, me too. Also, the thing with Mixsim 1.7.4 is the choice of impellers in the library is rather limited and there's not much guidance on how we can build other types of impellers such as helical ribbons (complicated structure) or anchor (which is quite a simple one). Have you ever built a new impeller and import it into Mixsim using the Add + Edit impeller feature?

Sorry, I have not. I am somewhat new to it, and I'm just looking "to use" Mixsim for it's impeller geometries so that I do not have to create one from scratch using "AutoCAD-type skills."

Perhaps in some time I might need to do that.

-Eric

You can construct helical ribbons, helical ribbons with a central screw (same pitch; use SET-CELLS in FLUENT 4 to convert the WALL cell in between the ribbon and the screw to .LIVE). Regarding anchors, you cannot create a clean geometry if your tank has a non-flat bottom. One thin you can do is create a default paddle (flat blade, 90 deg angle) then in FLUENT SET-CELLS to remove the paddle and add the anchor next to the wall.

Creating custom geometry is not that difficult once you graps the basics described in the Appendix of the MixSim Users Guide. The geometry of the blade is created from parallel curves (imagine a curves from the leading edge to the trailing edge of the blade) starting from the hub and moving outwards to the tip. You can build your hydrofoil, paddle type blade geometry in GAMBIT, split the face with concentric cylinders, split the resulting curves on the blade into multiple segments, delete all volumes, faces and edges leaving behind the vertices. Export these vertices (vertex coordinates) from GAMBIT and use them in your MixSim custom geometry file.

BTW, go to http://www.fluentusers.com/mixsim/library/index.htm to see a list of at least 24 impellers in the MixSim library.

TQ.

I'm using Fluent v5.5.14 with my Mixsim. Could you tell me how do I remove the paddle ... is it by specifying the paddle as e.g. interface or symmetry type? And how do I add the anchor next to the wall ... is it by modifying the grid built in Mixsim i.e. by separating, splitting or fusing zones?

My Mixsim version is 1.7.4 and Gambit v1.3...will that be okay to import - export the vertex coordinates? Another thing is export as what file from Gambit (file extension)? And do I import it into Mixsim using the Geometry -> Impellers -> Add -> Edit -> Geometric -> Import?

TQ very much.

You'll have to use FLUENT 4.5 for now. Once you've modified the grid you can import it into FLUENT 5 if you like. I suggest this route since you can use SET-CELLS to modify your sliding/mrf interfaces (the default interface zone is too close to the free surface for typical apps leading to long run times to reduce residuals).

Hence, all my previous suggestions were to use MixSim/FLUENT4 and use SET-CELLS in FLUENT4 to modify the tank internals and create the anchor impeller. This whole process can be quite tedious. If you are familiar enough with GAMBIT, build the impellers MixSim cannot in GAMBIT.

Regarding getting info from GAMBIT, you can get info on your vertices. This x, y, z coordinate info is written to the GAMBIT .trn file. Extract your vertex data from this file. Build your MixSim custom geometry file (see MixSim User Guide Appendix). Then use the Geometry -> Impellers -> Add -> Edit -> Geometric -> Import to bring in your blade geometry.

TQ.

I'll try the 2nd method because I've tried importing Fluent v4 .cas files into Fluent v5 b4 and got only 1 interior volume (instead of when I generated .cas file of Fluent v5 directly from Mixsim calculation, I got 3 interior volumes) and when I asked the TA at Fluent he said 1 interior volume doesn't seem right.

I'm not very familiar with Gambit so it might take a while for me to try the lethod you outlined but I'll inform you if I'm met with success. TQ again.

You use SET-CELLS as I mentioned previously to create the separate "fluid" zones. Go to the MixSim FAQ at http://www.fluentusers.com/mixsim/faq/index.htm for a description.

TQ. At the moment I'm still waiting for the User ID and password for fluentusers site but I'll do it as soon as I get it.

[rodeo]

hi my friends,

do you have mixsim software? I yes could you please send me a link?