Abstract: An aerofoil or hydrofoil (1) has a vessel (2) for providing a high velocity jet of fluid directed from a nozzle (3) in a direction having a component of velocity in the same direction as the required direction of lift (L). The aerofoil or hydrofoil (1) also has a curved surface (5) convex on the side of the aerofoil or hydrofoil which is in the direction of the required lift, and which serves to direct the velocity of the jet in a direction which is substantially opposite to the direction of the required lift or thrust force, the primary jet being directed over the convex surface for attachment thereto; and a duct formed over a rear part of the convex surface remote from the nozzle, whereby the primary jet of fluid flowing over and attached to the convex surface causes an enhanced flow through the duct, the duct being directed at least at its exit end in a direction so that the flow therethrough has a component of velocity opposite that of the required direction of lift.

Abstract: A jet pump comprises a nozzle (1) for a high speed primary flow, a mixing tube (2) into which the primary flow is directed by the nozzle (1), and an inlet (3) to the mixing tube (2) for a secondary flow, the inlet (3) surrounding the primary flow nozzle (1). Means (2') is provided for changing the cross section of the mixing tube (2) abruptly in order to produce a rise in static pressure immediately downstream, thereby increasing mixing of the primary and secondary flows, stabilizing the mixing process and enabling significant noise reduction when used in engine testing apparatus.

Abstract: A jet pump is provided for pumping a secondary fluid through a duct by injecting a primary fluid into the duct in the form of sheet-like jets lying in a plane parallel to the direction of flow of secondary fluid through the duct.

Abstract: A diffuser has an upstream duct, a downstream duct, the adjacent ends of the ducts defining a sudden enlargement of flow area. A fence arranged downstream of the downstream end of the upstream duct defines the upstream end of the downstream duct and has a free edge defining a flow area intermediate between that of defined by the adjacent ends of the two ducts. A chamber at the outside of the upstream duct has an opening defined by the downstream end of the upstream duct and the free edge of the fence. The ratio between the flow areas of the two ducts of their adjacent ends lies between 1.4 and a minimum greater than 1. The above ratio provides high diffuser effectiveness with little or no bleed from the chamber. Elements each comprising a diffuser as above may be arranged in flow-series to make possible a pressure rise greater than that given by a single element.

Abstract: The airflow from the compressor of a gas turbine engine into the combustion chamber or chambers principally comprises combustion air which enters the upstream end of the combustion chamber and dilution air which enters the combustion chamber at some point downstream of the combustion chamber inlet, the combustion air being made up of primary and secondary air entering the combustion chamber primary and secondary zones.In order to cope with the control of emissions from the combustion chambers, it is desirable to control the combustion air fuel ratio over the engine operating range by controlling air mass flow to the combustion and dilution zones of the combustion chamber. The invention proposes that this control can be achieved by providing a variable rate diffuser upstream of the primary, secondary and dilution air inlets, the variable rate diffuser comprising vortex generator having an associated variable air bleed.

Abstract: A combustion chamber of a gas turbine engine has an upstream variable rate diffuser for controlling the airflow into first and second annular ducts which partially surround the combustion chamber, primary and dilution air flowing into the combustion chamber from the first annular duct and bypass air flowing into the combustion chamber from the second annular duct. The variable rate diffuser comprises a primary duct and downstream fence located in a secondary duct which has a bleed duct with a variable bleed rate, the outlet of the primary duct being smaller in diameter than the inlet to the first annular duct.

Abstract: In a gas turbine engine having a can annular combustion system, the diffusion passage between the outlet annulus of the engine compressor and the inlets to the individual combustion chambers located in an annular casing, is partially defined diffusion control housings, one of each of which is located adjacent the upstream end of the respective combustion chamber. Each control housing is wedge-like in planform and has a downstream recess to accommodate the dome-shaped head of the combustion chamber. The control housing increases in circumferential width and radial height in the downstream direction to reduce the diffuser area ratio. Scoops can be provided to guide primary and dilution air into each combustion chamber.

Abstract: In a gas turbine engine having a can annular combustion system, the diffusion passage between the outlet annulus of the engine compressor and the inlets to the individual combustion chambers located in an annular housing, is partially defined by diffusion control housings, one of each of which is integral with the upstream end of a respective one of the combustion chambers. Each diffusion control housing is wedge-like in planform and increases in circumferential width and radial height in the downstream direction. An opening is provided to receive a fuel injector and an air outlet or inlets is located at the upstream end of each housing. The air inlet can be in the form of a single opening at the apex of the housing or in the form of an opening in each flank of the housing.