39results about How to "Broaden the stable operating range" patented technology

An instability mitigation system is disclosed, comprising a stator stage located axially proximate to a rotor, the stator stage having a row of a plurality of stator vanes arranged around a centerline axis, and a mitigation system comprising at least one plasma actuator mounted on the stator vane that facilitates the improvement of the stability of the rotor, and a control system for controlling the operation of the mitigation system. An instability mitigation system further comprising a detection system for detecting an onset of an instability in a rotor and a control system for controlling the detection system and the mitigation system are disclosed.

The invention belongs to the technical field of a compressor, in particular to a compressor stability expanding system and a compressor mechanism applied to the same. The compressor stability expanding system comprises a sensor, a backflow channel and a controller; the sensor is a vibration sensor or/and a pressure sensor; the backflow channel is provided with an opening and closing switch; the controller is used for receiving the information of the sensor and correspondingly controlling the opening and closing switch to realize the opening and closing operation. The invention also provides the compressor mechanism applied to the compressor stability expanding system; the compressor mechanism comprises a compressor enclosure cover plate; an annular air collection cavity is arranged in the compressor enclosure cover plate in a hollow mode; the annular air collection cavity is provided with air inlets and air outlets; the air inlets penetrate through the plate body of the compressor enclosure cover plate along the axial direction of a compressor wheel axle; the air inlet ports of the air inlets are positioned in the arc surface in the compressor enclosure cover plate; the backflow channel is arranged by being communicated with the annular air collection cavity. The aim that the compressor stability expanding system is more optimized is achieved.

A centrifugal compressor can be provided with which frequency of noise produced by rotation of the impeller having a plurality of blades does not resonate with natural frequency of vibration of gas in a plurality of axial slots which serve to increase gas flow rate in an operation range of increased gas flow rate and broaden stable operation range in an operation range of decreased gas flow rate resulting in reduction of noise caused by rotation of the impeller. The axial slots are formed between the peripheral part of the inlet passage of the compressor housing by the peripheral surface of the inlet passage and an annular ring part of the housing supported by a plurality of struts extending from the peripheral surface, four or more struts are provided to support the annular ring part, and all but one of them are located at positions which will be determined when all the struts are located at circumferentially equal spacing and one of the struts is shifted circumferentially from one of said positions by a certain central angle.

The invention discloses a single-phase cascade H-bridge grid-connected inverter control method under the weak grid and aims to realize stable operation of a cascaded photovoltaic inverter under the extremely weak grid. The method comprises following steps of (1) of DC side voltage control, the DC side voltage of each H-bridge unit is realized to track the maximum power point voltage; (2) of droopcontrol, a grid side current control command is obtained through a droop control equation and an AC voltage loop; and (3) of network side current control, independent control of the active current andthe reactive current can be realized, and an inverter modulation signal is generated. The method is advantaged in that advantages of both the droop control strategy and maximum power tracking are integrated, not only can the stable operation range of the cascaded H-bridge PV grid-connected inverter be expanded, but also maximum power tracking of each H-bridge unit can be realized.

The invention provides a nozzle for premixed combustion.A dilution zone is formed among the fluid outlet end of an inner-layer gas inflow structure, an outer-layer cylinder of an outer-layer gas inflow structure and the top ends of M layers of middle gas inflow structures, the influence of tempering on the nozzle and a combustor is lowered, and the tempering margin is increased.Oblique flow channels are formed between two adjacent wave rotational structures, between the corresponding wave rotational structure and an inner-layer cylinder and between the corresponding wave rotational structure and the outer-layer cylinder, combustion efficiency is improved, emissions of pollutants are reduced, flameout and flame pulsation are avoided, and the stability of combustion is improved.A drainage channel, an inner-side passageway and an outer-side passageway are formed by a supporting cylinder, the inner-layer cylinder and the outer-layer cylinder, and the stability, completeness and efficiency of combustion are further improved.

A lithographic apparatus comprises an illumination system configured to condition a radiation beam and a support constructed to support a patterning device. The lithographic apparatus further comprises a substrate table constructed to hold a substrate; and a projection system configured to project the patterned beam onto a target portion of the substrate. An active damping system is provided to dampen a vibration of at least part of the projection system. The active damping system comprises a combination of a sensor to measure a position quantity of the projection system and an actuator to exert a force on the projection system in dependency of a signal provided by the sensor. The active damping system is corrected to a damping mass, the damping mass being connected to the projection system.

The invention provides an atomizing nozzle, a nozzle array and a combustor. Fuel is atomized through an atomizing wave cyclone and is fully mixed with air, the combustion state is improved, the combustion stability is improved, the stable operation range is enlarged, the combustion efficiency is improved, and the effect of reducing pollutant emission is achieved. Due to an oblique flow channel, a low-speed area is generated near a center shaft of an outlet of the nozzle, the flame combustion rate and the rate of a reaction fluid flow field are balanced, and the phenomena of flameout and flame pulsation are avoided. Due to the adoption of a supporting cylinder, the fuel and air flowing speed can be more stable, the flow field is more stable, and the stability, completeness and efficiency of combustion can be further improved. The atomizing nozzle is switched between a diffusion combustion mode and a premixed combustion mode according to combustion conditions so as to be suitable for various working conditions and various kinds of fuel, and the combustion performance is greatly improved.

This invention relates to the field of very high current integrated power systems and defines a system where an alternating current inductive generator (13), controlled by a generator voltage regulator (14), is coupled to alternating current inductive load (11), controlled by an alternating current inductive load controller (12), all controlled by a supervisory control and data acquisition system (17) with externally adjustable power rate constraints (21) that define a new anticipatory mode integrated power system (10).

The present invention discloses a brushless doubly-fed motor feedforward current control system, a feedforward current controller and a design method thereof. The control system comprises a power grid, a brushless doubly-fed motor, a first converter, a second converter, a flux linkage computing module, an angle computing module, an angular speed computing module, a photoelectric coded disk, a feedforward current controller, a third converter, a fourth converter, an SVPWM pulse generator, a control winding side power converter and a direct current side; the feedforward current controller in thecontrol system is simple in control structure, compact, high in control precision, and rapid in current dynamic response; the system adds feedforward compensation on the basis of fully considering the whole current loop features of the control winding so as to greatly improve the control effect of the control winding state current and can achieve better stability and the faster dynamic performance; and moreover, the control system is high in stability, can effectively enlarge the stable operation range of the brushless doubly-fed motor and keep a good performance in different operation speeds.

The invention relates to an axial chute type processing casing with a back cavity for improving the performance of a gas compressor, and relates to a casing. A problem that a peak efficiency of the gas compressor is excessively reduced in the existing axial chute type processing casing is solved. The axial chute type processing casing comprises an outer shell (1), an annular rib (2) and an axial chute (3), wherein the annular rib (2) is embedded into the outer shell (1), the axial chute (3) is arranged on an inner hole of the annular rib (2) and the outer shell (1), a plurality of slot holes (3-1) are formed in the axial chute (3) in an annular array manner, and are respectively inclined on an axial direction and a radial direction, wherein an axial inclination angle of each slot hole (3-1) is (alpha), and alpha is equal to 10-35 degrees, a radial inclination angle of each slot hole (3-1) is (beta), and the beta is equal to 30-50 degrees; and a space enclosed between the outer shell (1) and the axial chute (3) is a back cavity (B). And the axial chute type processing casing is used for improving performance of the gas compressor.

A centrifugal compressor includes an asymmetric self-recirculating casing treatment that includes, on an inner face of a casing 10, a suction ring groove 1, a ring guide channel 2 and a back-flow ring groove 3 to form a self-recirculating channel. An axial-direction position S_r from an upstream end face of the suction ring groove to an impeller full blade leading edge 4 or a width b_r of the suction ring groove 1 is represented as A(α·D−β·D)²+A₀ and is distributed in a parabolic shape in a circumferential direction. An initial phase angle θ₀ is in a range of 0≦θ₀≦2π. A circumferential angle α of the casing has a definition range of θ₀≦α≦θ₀₊2λ. In the expression, A denotes a parameter of the parabola in the axial-direction position S_r or the width b_r, and A₀ denotes an extreme of the axial-direction position S_r or the width b_r when corresponding circumferential angle β and the α are equal at an extreme point of distribution of the parabola.

The invention discloses an arch-shaped high-energy-density blade design method and a designed vane pump thereof. The arch-shaped high-energy-density blade design method comprises the steps that the blade is provided with a first end and a second end in the extension direction and is provided with a hub side and a rim side in the blade height direction, and a wrap angle initial value, an inlet angle, a molded line and an outlet angle are included. The wrap angle initial value is a circumferential angle between the axial surface of each point on the first end and the hub side axial surface of the first end, and is determined by an arch curve of the blade; the inlet angle is formed between the tangent line of the axial surface streamline of the first end of the blade and the plane perpendicular to the axis of the hub, and is determined by a zero-speed circular rector criterion; the molded line is defined according to a distribution rule of a blade mounting angle along a relative axial surface flow line and is determined by axial surface flow calculation; and the outlet angle is formed between a tangent to an axial flow line of the second end of the blade and a plane perpendicular to the hub axis, and is calculated and determined by axial flow. According to the arch-shaped high-energy-density blade design method, the energy density of the blade pump can be effectively improved, and the stable operation interval of the pump can be widened.

A gas turbine combustion chamber is provided including a pilot fuel nozzle arranged in the central section of a cylinder that opens at one end towards a combustion chamber. The pilot fuel nozzle includes a fuel nozzle and a cylindrical outer casing around the outer circumference of the fuel nozzle. A pilot swirl element is arranged between fuel nozzle and outer casing, including a plurality of main burners which are arranged around the pilot fuel nozzle, and including a pilot cone having an inner side and an outer side. The pilot cone is arranged on the pilot fuel nozzle and an opening, such that a pilot flame is formed in the pilot cone by mixing air and pilot fuel in order to ignite a fuel injected by the main burners, wherein the pilot cone has turbulence generators on the inner side and/or outer side thereof.

The invention provides a swirler and a power system, and the swirler comprises a casing, a driving mechanism and a plurality of blades; the casing is provided with a first cover plate and a second cover plate which are oppositely arranged; each blade is provided with a rotating shaft, and the rotating shafts are rotationally connected with the first cover plate and the second cover plate; the driving mechanism is installed on the side, away from the second cover plate, of the first cover plate and provided with a plurality of output ends capable of rotating in a reciprocating mode, and each output end is correspondingly connected with the rotating shaft of one blade. According to the swirler, blade beating vibration and blade angle adjustability are achieved, the blade angle and the blade beating vibration frequency can be adjusted according to different working conditions of a combustion chamber, and therefore unstable combustion factors are actively restrained, and combustion stability is improved.

The invention relates to a vortex prevention column vortex elimination device and method of a rear wall of a sealed type water feeding tank. The vortex prevention column vortex elimination device comprises the sealed type water feeding tank and a water suction pipe, wherein a trumpet pipe is arranged at one end, arranged in the sealed type water feeding tank, of the water suction pipe; a trumpet opening is arranged on the trumpet pipe; the vortex prevention column is mounted at the rear side of the trumpet opening; one face, facing the trumpet pipe of the vortex prevention column, is a front panel; one face, opposite to the trumpet pipe, of the vortex prevention column is a rear panel; two faces, facing a side wall of the sealed type water feeding tank, are arc-shaped surfaces and the width of the front panel is less than the length of the rear panel; the length between the rear panel of the vortex prevention column and a rear wall of the sealed type water feeding tank is 0.12 to 0.21 time as much as the diameter of the trumpet opening; the height of the vortex prevention column is 1.8 to 2 times as much as the diameter of the trumpet opening. According to the vortex prevention column vortex elimination device and method, provided by the invention, the vortex prevention column is used for separating the water flow of the rear wall of the water feeding tank and filling a water body at a position with vortex and the water body is scattered so that the water body is recombined and a vortex velocity of the water flow is reduced, and furthermore, the effect of preventing wall attachment vortex of the sealed type water feeding tank from occurring is realized.