It looks like the question might be incomplete again. If you are asking about the two fuel flow laws in a particular context, could you clarify whether you're referring to internal combustion engines, fuel injection systems, or another specific field?
If you're asking about fuel flow laws in the context of thermodynamics or engine systems, there are commonly two types of fuel flow laws:
Mass Flow Rate Law - This is a fuel flow law where the fuel flow is proportional to the engine's speed or load, based on mass flow considerations.
Volumetric Flow Rate Law - This law deals with fuel flow based on the volume of fuel that the system can deliver over time.