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Old   December 7, 2009, 15:25
Default two-stroke engine
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Hello everybody,
I am a Ph.D. student and I need to simulate a two-stroke engine with Fluent. Does anybody have information or tutorials about that?
My mail is lamasgaldo@yahoo.es
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Old   December 7, 2009, 21:52
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Isabel,

I currently also working on 2 stroke engine for my master thesis.
I already able to create the engine with port and functioning. Just have no idea on how to use UDF to calculate the traped volume and other 2 stroke engine parameter.
Post ur question here see if able to help out.
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Old   December 9, 2009, 04:51
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Thank you very much, herntan.
My problem is that I am begining with my thesis and I don't have any information of how to simulate a two-stroke engine in Fluent.
Do you mind sending your master thesis to my mail? It would be very helpful for me.
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Old   December 10, 2009, 03:20
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Model up ur engine using CAD software / gambit first.

Send me the CAD data and i will show u what u need to do.
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Old   July 6, 2010, 03:24
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Hello herntan,

I have successfully modelled my mesh in SolidWorks and Gambit. I implemented it in Fluent, defined the movement of the piston and it works Ok.

Now I need to define how I am going to treat the two components. I have read the Fluent manual and I saw that I can implement the "VOF" or the "species transport" models. Which do you recommend?
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Old   July 6, 2010, 07:27
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What kind of fuel you are using?
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Old   July 7, 2010, 02:19
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I want to simulate the scavenging process, and not the combustion. So the kind of fuel is not important.
For the scavenging process, I do not know if is better the "VOF" model or the "species transport, no-premixed combustion" model
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Old   July 7, 2010, 10:47
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you don't need all those for air to air scavenging process.
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Old   July 8, 2010, 02:48
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Then, which is more appropiate, the "VOF" of the "species transport" model?
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Old   July 8, 2010, 07:35
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species transport is only for the simulation that have mixing of 2 different kind of fluid.
Since all of ur fluid is air, species transport is no needed at all.

VOF is for simulation when there is 2 type of fluid involve and the surface of contacting is very important. Some ppl use VOF to do bubble in water.
But again, since ur only have 1 kind of fluid, VOF is totally irrelavent.

Hope this help u out.
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Old   August 6, 2010, 05:57
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Hello Herntan,

I have succesfully modeled my engine and compared to experimental results. Now I want to calculate the scavenging efficiency, trapping efficiency and charging efficiency. Did you do that?
I read that there is an UDF written by Dr Xiao Hu which calculates the scavenging efficiency, but I do not know where I can find it.
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Old   August 6, 2010, 09:29
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Hi isabel and herntan,

I have a read a conference paper regarding the two-stroke scavenging calculation. He used VOF with 2 fluid. First he initiallized 100% fluid1 in the cylinder, next he intake fluid2. He then evaluate the ratio of those 2 fluids and relates them with scavenging efficiency.

Unfortunately, I have forgotten the reference paper information, but the year is either 2004 or 2005.

This maybe rather crude, but I hope this will spark you some idea.
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Old   August 6, 2010, 16:54
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I have the UDF in question, if you give me an e-mail adress I can send it to you. I am also doing a 2-stroke engine in Fluent for my MSc thesis. I am struggeling as well.
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Old   August 7, 2010, 02:54
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Dear Sir,

My model is square shape, 2D , simple model .The pink colour represent the reaction between reactant(e.g.glycerol with steam) , with the product (e.g. as hydrogen , carbon monoxide & carbon dioxide). I had key in the reactants & the products already by selecting:

->define
->materials
:name the each reactants & products
-Selecting material type : mixture
-Fluent mixture material : mixture-template
-key in all the reactants & products in properties (mixture species : name)
-key in number of mole for each reactant & product in properties(reaction:finite rate)

All the reactants & products can be obtain from the fluent database.

The red one represent the catalyst. I need to create the catalysts (e.g platinum-titanium oxide , platinum-silicon oxide and platinum-aluminium oxide ) . How should I do it?

CAn I directly change the mesh size in the gambit file ,than convert to mesh file ,to be open in fluent software??
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Old   August 10, 2010, 01:54
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Hello robot,

Effectively, you can change the mesh size in gambit. You can also change the mesh size in fluent.
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Old   August 10, 2010, 07:18
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Dear Isabel,

My problem here is, I had already draw the 2D model. The catalysts that I'm going to use are platinum-titanium oxide, platinum-aluminium oxide and platinum carbon. If the average size for platinum-carbon is 5nano meter ,how am I going to change the mesh size in gambit & fluent ? hope you can help me . Thanks you
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