Abstract: A filament reactor for producing diamond using chemical vapor deposition (CVD) techniques. The reactor includes a closed reaction chamber with at least one gas inlet and at least one exhaust port, two substrates disposed in the reaction chamber, and a resistance heating device in the form of a plurality of filaments positioned between the substrates. A preheater unit is located adjacent to the gas inlet for heating the gas mixture entering the reaction chamber. By preheating the gas mixture, the temperature of the substrates and the concentration of the hydrocarbon species fluxes are kept relatively uniform, thus ensuring high quality diamonds of uniform thicknesses. The preheater unit can be a serpentine tube made of a metal having a high thermal conductivity and wrapped with a resistance heating element.

Abstract: Carbon monoxide and unburned hydrocarbon burnout in gas turbine combustors is promoted by a combustor liner having a plurality of vortex generating members or ridges formed therein. The liner includes a substrate having an inner surface and a thermal barrier coating disposed on the inner surface. The vortex generating ridges are formed in the thermal barrier coating and extend transverse to the mean direction of flow through the liner. The thermal barrier coating is capped with a catalytic material which enhances carbon monoxide and unburned hydrocarbon oxidation. The ridges are defined by raised portions of the catalytic material and are of sufficient height to cause mixing between the hot flame products and the cool incompletely-burned flow along the liner wall. Alternatively, the ridges can be defined by forming corrugations in the substrate and disposing a uniform catalytically-active thermal barrier coating over the corrugated substrate.

Abstract: A trim system reduces NO.sub.x output from a cannular gas turbine by trimming fuel flow rates to equalize the fuel-air ratio in each combustor can. The system includes a main valve fluidly connected to the fuel inlet of each can and a trim valve fluidly connected to each fuel inlet in parallel with the main valve. Each trim valve has a flow resistance which is about 30-100 times greater than the flow resistance of each main valve. A controller is provided for controlling the opening of the trim valves in response to the level of NO.sub.x emitted from the gas turbine. The controller receives a signal corresponding to the NO.sub.x emissions from a NO.sub.x sensor and outputs suitable control signals to the trim valves. In one preferred control scheme, the controller sequentially perturbs the fuel flow rate to each can and monitors the resulting changes in NO.sub.x emissions. The controller establishes influence coefficients for each combustor can which are defined as the ratio of the change in NO.sub.

Abstract: A trim system reduces NO.sub.x output from a cannular gas turbine by trimming fuel flow rates to equalize the fuel-air ratio in each combustor can. The system includes a main valve fluidly connected to the fuel inlet of each can and a trim valve fluidly connected to each fuel inlet in parallel with the main valve. Each trim valve has a flow resistance which is about 30-100 times greater than the flow resistance of each main valve. A controller is provided for controlling the opening of the trim valves in response to the level of NO.sub.x emitted from the gas turbine. The controller receives a signal corresponding to the NO.sub.x emissions from a NO.sub.x sensor and outputs suitable control signals to the trim valves. In one preferred control scheme, the controller sequentially perturbs the fuel flow rate to each can and monitors the resulting changes in NO.sub.x emissions. The controller establishes influence coefficients for each combustor can which are defined as the ratio of the change in NO.sub.

Abstract: A supersonic combustion ramjet having a supersonic combustor. The supersonic combustor has a backward-facing step formed in a wall thereof and a forward-facing ramp formed in the wall downstream from the step. Hydrogen fuel is injected into the air flow by axially-directed fuel injectors disposed in the step and/or normally-directed fuel injectors disposed in the ramp. The ramp is inclined toward the center of the combustor so that fuel from the fuel injectors is turned into the main flow. The ensures rapid mixing which enables combustion to be completed within a distance on the order of one foot.

Abstract: A method for reducing the NO.sub.x produced by the engine of a supersonic aircraft. A reducing agent is injected into the combustor or the exhaust region of the engine. The reducing agent can be either hydrogen azide or hydrazine in an aqeuous form. For injection into the combustor, injection will be perpendicular to the main air flow through the engine and into a downstream portion of the combustor. Injection is carried out whenever NO.sub.x reduction is needed. By injecting the reducing agent into the downstream portion of the combustor or into the exhaust region, the reduction reaction is decoupled from the combustion process so that engine performance is not impaired.

Abstract: A fuel with or without fuel bound nitrogen (FBN) is burned in a high pressure machine (20 atm) comprising fuel and air compressors, combustor and turbine at an ER of about 2-3 and temperature below the threshold for creating thermal NO.sub.x. Prompt and FBN NO.sub.x are avoided due to the rich mixture, having a dearth of O and OH, producing CO and H.sub.2 and little CH. The turbine cools the products to reduce their temperature. The cooled products are mixed with the remaining air and burned at a temperature below the thermal NO.sub.x threshold temperature at an ER of about 0.6. Commercial stand alone machines can be used for the rich and for the lean combustors wherein air and fuel are supplied to the rich combustor and only air and the cooled combustion products of the rich machine are supplied to the lean combustor.

Abstract: A fuel with or without fuel bound nitrogen (FBN) is burned in a high pressure machine (20 atm) comprising fuel and air compressors, combustor and turbine at an ER of about 2-3 and temperature below the threshold for creating thermal NO.sub.x. Prompt and FBN NO.sub.x are avoided due to the rich mixture, having a dearth of O and OH, producing CO and H.sub.2 and little CH. The turbine cools the products to reduce their temperature. The cooled products are mixed with the remaining air and burned at a temperature below the thermal NO.sub.2 threshold temperature at an ER of about 0.6. Commercial stand alone machines can be used for the rich and for the lean combustors wherein air and fuel are supplied to the rich combustor and only air and the cooled combustion products of the rich machine are supplied to the lean combustor.