Strange pressure with dieselEngineFoam

tsencic · November 30, 2007, 11:35

I use dieselEngineFoam for combustion simulation. I noticed that mean cylinder pressure and temperature do not follow rules for adiabatic compression (my BC are adiabatic walls). I didn't notice it before since I was observing just the combustion period, but I noticed it when pressure and temperature were even decreasing during compression! It could be related to the fact that I receive the "added gas mas" different then 0 (sometimes negative) during compression. Is it a bug or I am doing something wrong?

tsencic · December 12, 2007, 05:39

Sorry, my mistake. My velocity (U) boundary conditions were wrong. I had zeroGradient, and there had to be fixedValue (0 0 0), and for the piston movingWallVelocity (0 0 0).

November 30, 2007, 11:35	I use dieselEngineFoam for com	#1
tsencic Member Tomislav Sencic Join Date: Mar 2009 Posts: 42 Rep Power: 18	I use dieselEngineFoam for combustion simulation. I noticed that mean cylinder pressure and temperature do not follow rules for adiabatic compression (my BC are adiabatic walls). I didn't notice it before since I was observing just the combustion period, but I noticed it when pressure and temperature were even decreasing during compression! It could be related to the fact that I receive the "added gas mas" different then 0 (sometimes negative) during compression. Is it a bug or I am doing something wrong?

December 12, 2007, 05:39	Sorry, my mistake. My velocity	#2
tsencic Member Tomislav Sencic Join Date: Mar 2009 Posts: 42 Rep Power: 18	Sorry, my mistake. My velocity (U) boundary conditions were wrong. I had zeroGradient, and there had to be fixedValue (0 0 0), and for the piston movingWallVelocity (0 0 0).

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