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Two problems with setup of BVM and ECFM.

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Old   March 1, 2018, 13:36
Default Two problems with setup of BVM and ECFM.
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Alex
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Still experimenting with combustion of premixed mixture (propane+air from flamelet library) in closed volume ignited with spark.
The grid has been reworked with smaller elements, 7-layers inflation along the walls, a 30-deg sector with rotational symmetry has been used instead of a whole cylinder, which significantly accelerated the simulation. Mainly SST-model was used.

There are two misunderstandings.
1. BVM shows similar results on different correlations. But with the increased pressure in the chamber - the reaction becomes slower. (For example, 3atm make flame 10% slower.) But this is not logical! The reaction should be accelerated at a higher pressure.
I tried to prescribe higher reference pressure in CFX RIF, change the turbulence settings and the grid - this did not change the result.

2. ECFM normally worked on a coarse grid (the reaction was faster with increased pressure), but stopped working on a detailed one. The reaction extends some distance from the spark and is infinitely slowed down. Smaller first timesteps, increasing the power and volume of the spark - all this did not bring results.

Perhaps I'm missing something too obvious.
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