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You will noticed I have dropped the "Division Size" down and I have upped the "Size" of the simulation to 30 x 40 x 30. I have also added a stock gasrepeatsolver node after the source_fuel_from_torus node to give the flame an extra boost.  Set Minimum Pass to 1. Turn on Override Minimum with Data.

Finally I made a few modifications to the pyrosolver node as noted below:

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