# dynamic meshing 2D compression piston

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 October 17, 2013, 04:09 dynamic meshing 2D compression piston #1 New Member   Marie Join Date: Oct 2013 Location: Knk Posts: 24 Rep Power: 9 Hello everybody, I am studying a 2D Compression in a piston. and my goal is having a speed of 5m/s for the piston and stop to make only one compression. In FLUENT I have specified the following for the Dynamic Mesh properties: - PistonHead = Rigid Body - : **piston-full** ; -topwall- stationary **piston-limit** - surfacebody = Deforming ; - sidewalls = deforming; I actually donīt know how to specified a velocity profile, so I have chosen " in-cylinder " option in the dynamic meshing. I have enabled Smoothing, and Remeshing. For the moment I am only considering the movement of the piston. When I am calculating, I got a result of the velocity field for exemple, but I have the impression that the mesh donīt move. So I have some questions : how can I insert a velocity profil ? is it possible to see the evolution in time of the geometrie? Thanks in advance,

 October 17, 2013, 08:00 #2 New Member   Marie Join Date: Oct 2013 Location: Knk Posts: 24 Rep Power: 9 Does anybody has a tutorial for Ansys 14,0 concerning moving mesh? Thanks

 November 18, 2013, 01:52 #3 Member   Vignesh KPV Join Date: Oct 2011 Location: Bangalore Posts: 83 Rep Power: 11 Hi Marie, Let me know If you have solved this problem. I'm struggling to simulate this problem. Please help me out if possible. Regards, Vignesh

April 19, 2015, 14:22
#4
Member

sanjeet Limbu
Join Date: Mar 2015
Posts: 91
Rep Power: 8
Dear friend,

I am using the ignition delay model for combustion by compression stroke of cylinder... simulation to rapid compression machine. The mixture fuel is inside the cylinder compressed at 30 millisec. The dynamic mesh used to show compression- for 30 millisec and combustion is expected after 30 millisec
I am able to run the dynamic mesh using the chem kin file for combustion . I got some results...
But I expected the combustion to make temperature rise,
If possible can u suggest if I entered any wrong input in initialization or model dialog box. I am using N2/Ar/O2/nC7H16: 58.5/30.9/10.307/0.00562 as fuel mixture

Unable to get temperature/pressure rise after compression stroke at 30 ms

Please suggest how to set up the model as pressure and very low CFD post results

Problem-
1. Pressure not rising during the compression stroke
2. temperature not rising till 30ms and getting raised at instantly- abrupt
3. No combustion happening after it gets to 700K+ temp
Attached Images
 temp profile.jpg (27.1 KB, 13 views) mixture fraction and variance.jpg (21.7 KB, 8 views) Temp and Presuree.jpg (22.9 KB, 5 views) Fuel oxidiser settings.jpg (38.7 KB, 7 views) Referance mesh needed.jpg (35.9 KB, 7 views)