Diesel engine in CFX 11.0

Kirillo · November 19, 2010, 06:10

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, 12:46

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

ghorrocks · November 19, 2010, 16:51

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, 10:56

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, 18:07

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, 06:13

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, 21:20

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, 07:05

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, 07:41

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, 10:14

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, 06:22

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, 12:03

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, 19:24

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

visitor · July 10, 2019, 05:06

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

November 19, 2010, 06:10	Diesel engine in CFX 11.0	#1
Kirillo New Member Kirill Join Date: Oct 2010 Location: Belarus, Minsk Posts: 3 Rep Power: 15	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.

November 22, 2010, 10:56	I trying...	#4
Kirillo New Member Kirill Join Date: Oct 2010 Location: Belarus, Minsk Posts: 3 Rep Power: 15	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.

July 8, 2019, 07:05	Setting up ignition time delay - fuel ignition begin when temperature is reached.	#8
visitor Senior Member AH Join Date: Apr 2014 Posts: 282 Rep Power: 13	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.

July 8, 2019, 07:41		#9
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	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. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

July 9, 2019, 19:24		#13
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	If you are doing this in Fluent then try the Fluent forum. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

November 19, 2010, 12:46		#2
joey2007 Senior Member Join Date: Mar 2009 Location: Europe Posts: 169 Rep Power: 17	I would use 12.1. There was some development on remeshing.

November 19, 2010, 16:51		#3
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	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

November 22, 2010, 18:07		#5
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	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.

November 23, 2010, 21:20		#7
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143	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.

July 8, 2019, 10:14		#10
visitor Senior Member AH Join Date: Apr 2014 Posts: 282 Rep Power: 13	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.

July 9, 2019, 06:22		#11
visitor Senior Member AH Join Date: Apr 2014 Posts: 282 Rep Power: 13	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. ...

July 10, 2019, 05:06		#14
visitor Senior Member AH Join Date: Apr 2014 Posts: 282 Rep Power: 13	The original intention was to go either way, cfx or fluent. Still open.

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