For pyrotechnic-type effects you can enable combustion by using the burn option in the forces tab.
The burn option controls the rate at which fuel is removed from the simulation.
The combustion tab then lets you set the rules for the resulting reaction.
The Ignition Temperature controls at what temperature fuel will be allowed to burn, This can also be controlled with a control ramp if you need to do something more complex like only letting fuel burn if it is moving very slowly.
Advect Fuel allows the fuel in the simulation be advected with the rest of the fields. Sometimes with an effect like burning wood you may want to have your fuel stay static, but with a flame thrower fuel material is shot out and mixes with the air.
Burn Inefficiency controls how much of the burnt fuel is actually removed from the simulation. This is helpful if you want fuel to burn but not actually be removed from the sim making it last longer without needing to actually inject more fuel.
Threshold allows you to only burn fuel values below this amount. Any fuel value above the threshold will not be allowed to ignite until it diffuses naturally and goes below this value. This is good for doing air-fuel mixture type effects.
For every unit of fuel burnt, how much of each of these values do you want to introduce into the simulation? Density emits density, temperature emits temperature, and pressure emits pressure that causes your simulation to expand outwards. Be careful not to add in too much pressure or else the simulation might expand too fast.
