There is disclosed a centrifugal compressor including an impeller rotatable about an axis and a diffuser downstream of the impeller. The diffuser has walls delimiting flow passages. Plasma actuators are positioned adjacent the walls and are operatively connectable to a source of electricity. The plasma actuators have a first electrode, a second electrode, and a dielectric layer therebetween. The first electrode is upstream of the second electrode. The first electrode is exposed to the flow passage. The second electrode is shielded from the flow passage by the dielectric layer. The plasma actuators are operable to generate an electric field through the dielectric layer. The plasma actuators are located closer to inlets of the flow passage than to outlets of the flow passages. A method of operating the compressor is disclosed.

A combustion engine (10) comprises a radial compressor (16) in flow communication via a flow passage (22) with a compressor-combustor array (20) radially outward of the radial compressor (16), both rotatable around a central axis (12). The compressor-combustor (20) comprises an array of rotor blades (26). The walls of the blades (26) define a plurality of chambers (28, 30). Each chamber (28, 30) has a flow inlet (32) to receive fluid from the radial compressor (16), and a flow outlet to exhaust fluid radially outwards from the compressor-combustor (20). The plurality of chambers (28, 30) comprises a first pilot combustion chamber (28a) and a second pilot combustion chamber (28b). The first pilot combustion chamber (28a) is provided with a first fuel injector (40a), and the second pilot combustion chamber (28b) is provided with a second fuel injector (40a). The first fuel injector (40a) is in flow communication with a first fuel reservoir (70a), and the second fuel injector (40b) is in flow communication with a second fuel reservoir (70b). The first fuel reservoir (70a) and the second fuel reservoir (70b) are each in fluid communication with a flow regulator (100), the flow regulator (100, 200, 300) operable to vary fuel flow delivery rate to the first reservoir (70a) and vary fuel flow delivery rate to the second reservoir (70b). The differential regulation of fuel flow between pilot combustion chambers results in different levels of thrust being generated downstream of the combustion chambers. In this way the engine is operable to produce vectored thrust.

A combustion engine (10) comprises a radial compressor (16) in flow communication via a flow passage (22) with a compressor-combustor array (20) radially outward of the radial compressor (16), both rotatable around a central axis (12). The compressor-combustor (20) comprises an array of rotor blades (26). The walls of the blades (26) define a plurality of chambers (28, 30). Each chamber (28, 30) has a flow inlet (32) to receive fluid from the radial compressor (16), and a flow outlet to exhaust fluid radially outwards from the compressor-combustor (20). The plurality of chambers (28, 30) comprises a first pilot combustion chamber (28a) and a second pilot combustion chamber (28b). The first pilot combustion chamber (28a) is provided with a first fuel injector (40a), and the second pilot combustion chamber (28b) is provided with a second fuel injector (40a). The first fuel injector (40a) is in flow communication with a first fuel reservoir (70a), and the second fuel injector (40b) is in flow communication with a second fuel reservoir (70b). The first fuel reservoir (70a) and the second fuel reservoir (70b) are each in fluid communication with a flow regulator (100), the flow regulator (100, 200, 300) operable to vary fuel flow delivery rate to the first reservoir (70a) and vary fuel flow delivery rate to the second reservoir (70b). The differential regulation of fuel flow between pilot combustion chambers results in different levels of thrust being generated downstream of the combustion chambers. In this way the engine is operable to produce vectored thrust.

A diffuser for a compressor of a gas turbine engine is disclosed. The diffuser has a plurality of diffuser pipes circumferentially distributed about an axis of the compressor, each of the plurality of diffuser pipes extending from an inlet to an outlet and having a bend section between the inlet and the outlet, a low pressure side and an opposite high pressure side. A recirculation conduit defines a recirculation path from a first flow region to a second flow region in one or more of the plurality of the diffuser pipes, the first flow region having a greater static pressure than that of the second region, the recirculation conduit having a conduit inlet and a conduit outlet, at least the conduit outlet located within the low pressure side of one of the plurality of the diffuser pipes.

A diffuser for a compressor of a gas turbine engine is disclosed. The diffuser has a plurality of diffuser pipes circumferentially distributed about an axis of the compressor, each of the plurality of diffuser pipes extending from an inlet to an outlet and having a bend section between the inlet and the outlet, a low pressure side and an opposite high pressure side. A recirculation conduit defines a recirculation path from a first flow region to a second flow region in one or more of the plurality of the diffuser pipes, the first flow region having a greater static pressure than that of the second region, the recirculation conduit having a conduit inlet and a conduit outlet, at least the conduit outlet located within the low pressure side of one of the plurality of the diffuser pipes.

A power module includes a turbine arranged along a rotation axis, an interconnect shaft fixed in rotation relative to the turbine, and a compressor with a regenerative compressor wheel. The regenerative compressor wheel is fixed in rotation relative to the interconnect shaft supported for rotation with the turbine about the rotation axis. Generator arrangements, unmanned aerial vehicles, and methods of generating electrical power are also described.

A gas turbine engine comprises, in fluid flow series, a gas-generator compressor, a combustor, a gas-generator turbine, and a free power turbine. The gas-generator compressor is an axi-centrifugal compressor comprising a plurality of axial compression stages followed by a single centrifugal compression stage, wherein the International Standard Atmosphere, sea-level static (hereinafter ISA SLS) design point pressure ratio of the axi-centrifugal compressor is from 12 to 16, and a ratio of the ISA SLS pressure rise across the axial compression stages to the ISA SLS pressure rise across the centrifugal compression stage is from 0.75 to 1.

A gas turbine engine comprises, in fluid flow series, a gas-generator compressor, a combustor, a gas-generator turbine, and a free power turbine. The gas-generator compressor is an axi-centrifugal compressor comprising a plurality of axial compression stages followed by a single centrifugal compression stage, wherein the International Standard Atmosphere, sea-level static (hereinafter ISA SLS) design point pressure ratio of the axi-centrifugal compressor is from 12 to 16, and a ratio of the ISA SLS pressure rise across the axial compression stages to the ISA SLS pressure rise across the centrifugal compression stage is from 0.75 to 1.

High performance wedge diffusers utilized within compression systems, such as centrifugal and mixed-flow compression systems employed within gas turbine engines, are provided. In embodiments, the wedge diffuser includes a diffuser flowbody and tapered diffuser vanes, which are contained in the diffuser flowbody and which partition or separate diffuser flow passages or channels extending through the flowbody. The diffuser flow channels include, in turn, flow channel inlets formed in an inner peripheral portion of the diffuser flowbody, flow channel outlets formed in an outer peripheral portion of the diffuser flowbody, and flow channel throats fluidly coupled between the flow channel inlets and the flow channel outlets. The diffuser vanes include a first plurality of vane sidewalls, which transition from linear sidewall geometries to non-linear sidewall geometries at locations between the flow channel inlets and the flow channel outlets.

A power module includes a turbine arranged along a rotation axis, an interconnect shaft fixed in rotation relative to the turbine, and a compressor with a regenerative compressor wheel. The regenerative compressor wheel is fixed in rotation relative to the interconnect shaft supported for rotation with the turbine about the rotation axis. Generator arrangements, unmanned aerial vehicles, and methods of generating electrical power are also described.