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 discloses a secondary splitter blade type centrifugal impeller, comprising a long blade extending from impeller inlet to impeller outlet. The suction surface of the long blade and the pressure surface of an adjacent long blade form a complete air flow passage; wherein a middle blade is arranged between the two long blades to form a primary splitter blade; the two sides of the middle blade are respectively provided with a short blade to form a secondary splitter blade; the inlet of the middle blade deflects toward the suction surface in the air flow passage; the inlet at the wheel disc side of the short blade deflects towards the suction surface in the air flow passage, and the inlet at the wheel cap of the short blade deflects towards one side of the pressure surface in the air flow passage; the number ratio of the long, middle and short blades is 1:1:2; and the long, middle and short blades are evenly distributed at the periphery of the outlet of the impeller. The centrifugal impeller of the invention gradually increases splitter blades, and can effectively allocate blade passage gas flow and blade aerodynamic load, improve flow uniformity at the impeller outlet and improve pressurizing capacity and steady operation range of the centrifugal impeller.

The invention discloses a hybrid modulation strategy based power balance control method for a cascade H-bridge inverter and aims to solve a problem of incapability of stable operation of a system due to input power imbalance of a photovoltaic battery panel on a DC side of the photovoltaic inverter. The method includes steps of 1, master DC side voltage control used for realizing maximal power point voltage tracking by H-bridge unit DC side voltages and obtaining a system active current command value; 2, grid side current decoupling control capable realizing independent control of active current and reactive current and generating inverter total modulation wave voltage; 3, inter-unit power balance control including determining the correct switching states of each H-bridge unit so as to realize the power balance control among the H-bridge units and the maximal power tracking of the H-bridge units through DC side voltage error ranking of the H-bridge units. The method can be suitable for different kinds of working conditions. By adopting the method, stable operation of the cascade H-bridge photovoltaic inverter in a comparatively large range and system power generation capacity can be guaranteed.

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.

The invention relates to an axial and radial flowing compressor with an axial chute processor casing structure, belonging to the technical field of impeller machinery; the axial and radial flowing compressor comprises an axial flowing rotor, an axial flowing stator and a radial-flowing compressor which are coaxially connected sequentially; axial chutes which are circumferentially distributed uniformly are processed on a casing wall surface of the axial flowing rotor of the axial and radial flowing compressor, the axial chute is radially inclined with 30-60 degrees along the rotating direction of the rotor. In the axial and radial flowing compressor with the axial chute processor casing structure, the low-energy tip clearance vortex of axial-flowing grade blade tip can be effectively controlled under the pumping action of the axial chute processor casing on the axial flowing rotor, flow separation is inhibited under a low flow-rate condition, the entrance condition of the radial flowing compressor is improved, so as to improve surge-to-stall margin of the axial and radial flowing compressor greatly on the premise of ensuring the little change of pressure ratio and efficiency.

The invention provides a multi-stage compressor and a refrigerating system provided with the same. The multi-stage compressor comprises a plurality of stages of compression cavities, diffusers (40) and air supplying structures (50). An impeller is arranged in each stage of compression cavity. An air passing channel (20) is arranged between every two adjacent stages of compression cavities. Every two adjacent stages of compression cavities are divided into an upstream compression cavity (11) and a downstream compression cavity (12). The diffusers (40) are arranged in the air passing channels (20). The air supplying structures (50) are arranged on at least one air passing channel (20) and located between the diffusers (40) corresponding to the upstream compression cavities (11) and the downstream compression cavities (12), or the air supplying structures (50) are located in the diffusers (40). By the adoption of the technical scheme, the problems that in the prior art, a compressor is prone to operating unstably, the circulating efficiency of a refrigerating system is low, and pneumatic noise is high can be effectively solved.

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 discloses a pulverized coal combustion device which is capable of combusting coal with poorer quality and aims at being used for an industrial boiler. The combustion device comprises an inner barrel and an outer barrel; and a pulverized coal start-up burner, a central burner, an annular burner, a sandwich secondary air port, a cyclone secondary air port and a direct secondary air port are arranged on the combustion device. When the start-up burner is in a stable burning state, the central burner and the annular burner can be guaranteed to stably and fully burn pulverized coal with different quality; and the burning temperature is controlled by cold air volume, so that a large amount of NOx pollutants can be prevented from being generated.

The invention discloses a control method for expanding the stable running range of a cascaded H-bridge photovoltaic grid-connected inverter. The method comprises the following steps of detecting output voltages and currents of all photovoltaic cell modules, a power grid voltage and a power grid current on line; judging whether the system can stably run or not according to the size of an effective value of the power grid current and the size of critical current of an inverter during unit power factor running; calculating an angle of the power grid current advancing the power grid voltage when the system cannot stably run, and compensating reactive power; and judging whether a power factor of the system is lower than 0.9 or not, maintaining the power factor to be 0.9 if the power factor is lower than 0.9, enabling the photovoltaic module with relatively large output power to exit from maximum power point running so as to balance power among the modules. By the method, the stable running range of the cascaded H-bridge photovoltaic inverter can be effectively expanded, and moreover, not too low power generation quantity and power factor of the system can be ensured.

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.

The invention relates to a vortex-eliminating device and method for an anti-vortex column on the rear wall of a closed water inlet pool, comprising a closed water inlet pool and a water suction pipe, one end of the water suction pipe placed in the closed water inlet pool is provided with a trumpet tube, There is a bell mouth on the top; an anti-vortex column is installed behind the horn tube, the side of the anti-vortex column facing the horn tube is the front plane, the side facing away from the horn tube is the rear plane, and the two sides facing the side wall of the closed water inlet pool are curved surfaces , the width of the front plane is smaller than the length of the rear plane; the length of the rear plane of the anti-vortex column from the rear wall of the closed water inlet pool is 0.12 to 0.21 times the diameter of the bell mouth; the height of the anti-vortex column is 1.8 to 1.8 times the diameter of the bell mouth 2 times. Through the present invention, the water flow at the rear wall of the water inlet pool is separated by the anti-vortex column, and the water body at the position where the vortex occurs is filled, the water body is broken up, the water body is recombined, and the vortex velocity of the water flow is reduced, so as to prevent and control the closed water inlet pool The role of wall vortices.

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 Sr from an upstream end face of the suction ring groove to an impeller full blade leading edge 4 or a width br 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 Sr or the width br, and A0 denotes an extreme of the axial-direction position Sr or the width br 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.

A high-speed generator using magnetic powder and a binding material rotor is characterized in that a motor comprises a casing (1), a stator, and a layered binding hybrid permanent magnet rotor, and the stator and a rotor are disposed in the casing (1). Such structure can effectively reduce a heat source in the rotor of the motor and fundamentally solve the problem of overheating of the rotor of the high-speed generator. In addition, such structure ensures the uniformity, integrity and consistency of the rotor of the motor, and can mechanically solve the problem that the permanent magnet is broken by the large tensile stress under the condition of high-speed rotation.

The invention discloses a design method of an arcuate high energy density blade and a designed blade pump. The blade design method is as follows: the blade has a first end and a second end in the extension direction and a hub side and a rim side in the blade height direction, including the initial value of the wrap angle, the inlet angle, the profile line and the outlet angle. The initial value of the wrap angle is the circumferential angle between the axial surface of each point on the first end relative to the axial surface of the hub side of the first end, which is determined by the arcuate curve of the blade; the inlet angle is formed by the axial streamline of the first end of the blade. The distance between the tangent line and the plane perpendicular to the hub axis is determined by the zero velocity circulation criterion; the profile line is defined according to the distribution law of the placement angle of the blade along the relative axial streamline, and is determined by the axial flow calculation; the outlet angle is formed in the blade Between the tangent of the axial streamline of the second end and the plane perpendicular to the axis of the hub, it is determined by the axial flow calculation. The blades obtained by the blade design method of the invention can effectively improve the energy density of the vane pump and widen the stable operation range of the pump.

An outer-rotor high-speed generator using circumferential integral composite permanent magnet structure is characterized in that: the high-speed motor comprises an outer rotor and a stator disposed inthe outer rotor; the stator is disposed in an axial through hole of the outer rotor; and a gap is arranged between the outer rotor and the stator. Such structure can reduce a heat source in the rotorof the motor, and solve the overheating of the rotor of the high-speed motor fundamentally. In addition, such structure ensures the uniformity, the integrity and the consistency of the rotor of the motor, and can mechanically solve the problem that the permanent magnet is broken by the large tensile stress under the condition of high-speed rotation.

The centrifugal compressor stability expansion method of the double-function coupling surface regulating diffuser end wall of the present invention comprises: firstly, by performing geometric modeling and numerical simulation on the original centrifugal compressor with bladed diffuser, analyzing The flow structure that induces instability, find out the most critical position that induces the sign of compressor stall, and determine the wall of the vane diffuser hub where the sign of stall occurs is determined as the key position of the shape; then, according to the flow law, the conventional planar end wall is transformed into a concave-convex shape The dual-function coupling profile with undulating characteristics can flexibly construct different forms of concave-convex end walls by adjusting the three profile control parameters. periodic array. The invention changes the flow velocity and pressure distribution near the wall by changing the geometric shape of the flow channel, effectively inhibits the flow separation of the centrifugal compressor under the small flow condition, delays the occurrence of rotational stall and surge, and thus broadens the stable operation range of the centrifugal compressor.