A combustor assembly of a turbine engine is provided with a mechanical air regulation unit which selectively varies the amount of air being delivered into a combustion zone of the combustor based upon a pressure of a fuel being supplied to the combustor. A first type of air regulation unit would act to increase the amount of air entering the combustion zone when greater amounts of a high heat value fuel are being delivered to the fuel nozzles of the combustor. A second type of air regulation unit could act to decrease the amount of air entering the combustion zone when greater amounts of a low heat value fuel are being delivered into the combustor through fuel nozzles.