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-   -   Diesel engine in CFX 11.0 (https://www.cfd-online.com/Forums/cfx/82193-diesel-engine-cfx-11-0-a.html)

Kirillo November 19, 2010 07:10

Diesel engine in CFX 11.0
 
Kind time of day!
I am engaged in calculation income air in the chamber of combustion of the diesel engine. All calculations is produced in ANSYS CFX 11.0. FE mesh of model has constructed, has entered train diagrams of walls. Now I think, how during calculation it is possible to disconnect separate sub-domains to model all cycle of hit of air in the chamber of combustion, its compression and the subsequent outcome. Help informative advice! Settlement model I can send on your e-mail.
My regards.
P.S.: Sorry for my English.

joey2007 November 19, 2010 13:46

I would use 12.1. There was some development on remeshing.

ghorrocks November 19, 2010 17:51

There are few approaches to this:

You can use a GGI as that allows you to slide to no contact no problems, but you will need to change the geometry slightly to fit it in.

You can also move the valve to almost shut then interpolate onto a mesh with the valve shut. This way you miss the final little bit of valve motion but not much happens there anyway.

And you might be interested to read my phd thesis on using CFX4 to model IC engines. http://hdl.handle.net/2100/248

Kirillo November 22, 2010 11:56

I trying...
 
Kind time of Day!

I try the first variant as I wish to model a full cycle of work of the chamber of burning. I already download earlier also have seen your book. Me concrete adjustments GGI, boundary condition of a wall interest. I have noticed, what the wall simply ceases to spend air on time or I not so I understand statement of a problem?

I trying that http://www.keithwakeham.com/8936/Files/bauer.pdf

This is My experiment: http://files.mail.ru/EZGTKW (it's 3D in cut plane) (file is downloadable before 27 november 2010)

I want to activate and deactivate entrance channels in various time of experiment.

My regards.

ghorrocks November 22, 2010 19:07

The presentation you linked to uses the new meshing stuff to model the motion. This stuff is much improved in V12 (and I think V13 has further developments) so I would recommend updating.

I did not understand your question.

Kirillo November 23, 2010 07:13

1 Attachment(s)
Kind time of Day!

My question is: how to activate and deactivate domain by the use of wall (or GGI) between domains in ANSYS CFX 11.0? Wall will be on\off by time curve.

My regards.

ghorrocks November 23, 2010 22:20

I gave two methods to do it in my first post. Either slide shut with a GGI or stop the valve just before closing and interpolate onto a mesh with the valve shut.

visitor July 8, 2019 08:05

Setting up ignition time delay - fuel ignition begin when temperature is reached.
 
Just started reading this thread, interesting. I have a student version, will see if I can simulate HCCI combustion.

Need to figure out time delay for fuel ignition. Maybe with an IF function, if temperature is greater than 270C, then ignition. Unless there is an option in fuel ignition which does this automatic. Will make a start and share information using CFX.

ghorrocks July 8, 2019 08:41

ANSYS has a IC engine simulation software suite called Forte. Doing IC engine modelling in CFX is definitely doing it the hard way these days. You should look at Forte.

visitor July 8, 2019 11:14

Yes I have seen this. However I will attempt a much simpler model. Basically I am thinking of just on cylinder volume with just the bottom wall boundary condition moving up and down. At the top air fuel inlet and one exhaust outlet, boundary condition. Haven't started, just thinking about CFX, but may go for fluent.

Will share outcome once I start. HCCI combustion is similar to diesel, but uses petrol. Somehow I need to link ignition of petrol with the compressed air/fuel/temperature.

visitor July 9, 2019 07:22

Got a cylinder compression model going using fluent. Basically a cylinder with an inlet and a outlet at the top. The bottom of cylinder moves up and down following a profile.

Now if I want control combustion of pentane C5h12 which is petrol spray, how can I link it's ignition to temperature in cylinder. When air is compressed, temperature increases and set petrol to ignite. I was thinking about a udf which measures temperature, but how do I link this with ignition.?

In c++
...
If temperature >=800 // temperature in K.
Then ignition of fuel.

...

visitor July 9, 2019 13:03

1 Attachment(s)
Here is this interesting section in fluent, section 19.2.3. Menu inputs for ignition delay, Generalised is about right for compression ignition.

Just need to find out inputs for petrol premixed combustion. See attached menu.

ghorrocks July 9, 2019 20:24

If you are doing this in Fluent then try the Fluent forum.

visitor July 10, 2019 06:06

The original intention was to go either way, cfx or fluent. Still open.


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