Abstract: An external combustion system for a stationary gas turbine engine includes a rich zone combustor, a water or steam quench stage, a lean zone combustor and a dilution stage. Fuel such as natural gas or liquid hydrocarbon, which forms no ash or slag, burns in a primary air supply in the rich zone combustor at an equivalence ratio exceeding 1 which inhibits rapid formation of of oxides of nitrogen. The effluent from the rich zone combustor is a stream of combustible gas including carbon monoxide and hydrogen. The combustible gas stream is quenched in the quench stage and mixed with a secondary supply of compressed air in the lean zone combustor. The combustible gas ignites spontaneously in the lean zone combustor and burns at an equivalence ratio of less than 1 and at a temperature below the range characterized by rapid formation of oxides of nitrogen.

Abstract: In a coal combustion system suitable for a gas turbine engine, pulverized coal is transported to a rich zone combustor and burned at an equivalence ratio exceeding 1 at a temperature above the slagging temperature of the coal so that combustible hot gas and molten slag issue from the rich zone combustor. A coolant screen of water stretches across a throat of a quench stage and cools the combustible gas and molten slag to below the slagging temperature of the coal so that the slag freezes and shatters into small pellets. The pelletized slag is separated from the combustible gas in a first inertia separator. Residual ash is separated from the combustible gas in a second inertia separator. The combustible gas is mixed with secondary air in a lean zone combustor and burned at an equivalence ratio of less than 1 to produce hot gas motive at temperature above the coal slagging temperature.

Abstract: Supersonic rotor blading in an axial-flow fan or compressor employs blades such that shock waves originating on a blade are canceled at the intersection of the wave and the surface of an adjacent blade by virtue of a blade configuration such that the shocks intersect the blade surface at a line of properly oriented change in flow angle of the blade surface. A three-wave system is employed.