221results about How to "Inhibition of flow separation" patented technology

A ventilation device that enhances the longitudinal thrust of a fan (2) installed within a tunnel, by the introduction of a convergent nozzle (7) to accelerate the outlet flow (8). An angled transition piece (6) can turn the flow by a specific angle (36). Multiple fans can be connected to common inlet and outlet plenums, supplying one or more convergent nozzles. Bi-directional flow can be achieved by fitting convergent nozzles to both sides of a fan, with bypass dampers optionally installed between the fan and the two nozzles. The nozzle trailing edge can be shaped with multiple lobes, chevrons or tongues, and the fan centre-body can be shaped with multiple lobes. A fire suppression agent such as water mist can be supplied into the ductwork between the fan and the nozzle trailing edge. Acoustic silencing can be achieved using the absorbent material on the nozzle and fan centre-body.

Disclosed are a plasma control device and method for blades of a wind driven generator. A plasma exciter is composed of an exposed electrode, an implantation electrode and a medium blocking layer, wherein the exposed electrode and the implantation electrode are pasted to the upper surface and the lower surface of the medium blocking layer respectively; the exposed electrode is exposed in air and connected with the high pressure end of an excitation power supply (7); the surface of the implantation electrode is wrapped by insulation materials, and the implantation electrode is connected with a ground electrode. The plasma exciter is installed on the surfaces of the blades of the wind driven generator smoothly. According to the environment where the wind driven generator is located and freezing parameters of the surfaces of the blades, a control system (11) adjusts the output waveform, potential, frequency and duty ratio of the excitation power supply (7), and controls the excitation power supply to be opened and closed. The plasma exciter produces air discharge under the action of the high voltage of the excitation power supply (7), produced plasma has the impact function, the acceleration function and the heating function on ambient air, flow separation on the surfaces of the blades of the wind driven generator is restrained, and icing is prevented and removed.

A blade for use in a wind turbine comprises a pressure side and suction side meeting at a trailing edge and leading edge, the pressure side having a pressure side surface and the suction side having a suction side surface, the pressure side surface and suction side surface for providing lift to the turbine blade upon the flow of air from the leading edge to the trailing edge and over the pressure side and suction side surfaces, the pressure side and suction side extending from a root portion to a tip portion of the turbine blade. In some situations, the root portion is non-aerodynamic. The aerodynamics of such a blade is improved with the aid of pneumatic blowing through one or more blown passages for providing pressurized air (or other fluid) to a suction side and/or pressure side of the blade.

A diffuser arrangement through which a fluid may flow is provided. The diffuser includes an outer diffuser comprising an inner surface, and a flow-guiding device, which is configured such that at least part of the boundary layer flow forming on the inner surface of the outer diffuser can be accelerated in the main flow direction, so that a flow separation is prevented on the inner surface of the outer diffuser. Also provided are an exhaust steam plenum of a steam turbine and an exhaust gas plenum of a gas turbine, both including a diffuser arrangement.

A gas turbine engine combustor inlet diffuser assembly has at least one diverging annular wall including a flowpath surface bounding a diffuser flowpath. An annular blowing slot is axially located along the annular wall and an annular blowing air flowpath leads to and is in fluid communication with the blowing slot. An annular array of scoops disposed in the diffuser flowpath downstream of the blowing slot have upstream facing openings and are in fluid communication with the blowing air flowpath. The annular scoops are supported on hollow struts. Each of the hollow struts has at least one radially extending flow passage for directing blowing air from the scoop to the blowing air flowpath. The blowing slot opens in a downstream direction with respect to the diffuser flowpath. A row of blowing air compressor blades disposed across the blowing air flowpath may be used to pump up the pressure of the blowing air.

The invention provides a high-efficiency pneumatic layout structure of synergistic jet for a high-altitude propeller and a control method. The high-efficiency pneumatic layout structure is characterized in that a plurality of synergistic jet devices are distributed along propeller blades of the propeller in a spanwise sectional manner; each synergistic jet device comprises an air blowing opening formed in a negative-pressure area of the front edge of the upper surface of the propeller, an air suctioning opening formed in a high-pressure area of the rear edge of the upper surface of the propeller, an airflow pipeline arranged in the paddle and an air pump arranged in the airflow pipeline; the air blowing opening and the air suctioning opening are communicated by the airflow pipeline to form an air-blowing and air-suctioning loop; the air pump is used for driving air suctioning and air spraying to be implemented simultaneously, and by control of the air pump, the air suctioning amount and the air spraying amount are same. The high-efficiency pneumatic layout structure provided by the invention has the advantages that the defects of the traditional propeller layout and the common flow control technology can be made up, and the working efficiency of a propelling system of the high-altitude propeller can be improved.

A centrifugal compressor with an air-bleed and a jetting box construction belongs to the turbo-machine field. The invention is characterized in that the wall of the box of worm frame is arranged with at least three exhaust-injection guide channels uniformly arranged around the rotary axle of compressor, while it contains exhaust channels and injection channels. The opening of the exhaust channels is arranged at the wall at the inlet of the non-blade expander channel, and vertical to the wall of inlet box. The opening of the injection channel is at the most torsion of the channel formed by the worm frame and blade, while it is at same direction of main absolute speed of most torsion. The exhaust channel and the injection channel are connected via the guide channel. The inventive exhaust-injection guide channel can exhaust the adhere layer at the wall of expander, restrain the flow separation of expander, and fill high-energy injection into the channel of blade wheel, to restrain the flow separation of adsorption face and restrain the flow separation at small flux, to improve the speed-lost allowance and efficiency.

A method of reducing aerodynamic drag on a moving blunt-edged body, the method comprising actively generating a flow of air at a blunt edge of a body and using the generated flow of air to control an external flow of air moving relative to an edge of a moving blunt-body.

The invention relates to a plasma flow control method for suppressing the flow separation of a suction surface of a wind turbine blade. The plasma flow control method comprises the following steps of: asymmetrically distributing two metal electrodes at both sides of an insulating material to form a group of plasma exciter, wherein one metal electrode is exposed in the air, while the other metal electrode is embedded in the insulating material; arranging at least one group of plasma exciter on the suction surface of the wind turbine blade in a mounting mode capable of ensuring that a plasma induced flow direction is the same as a main flow direction; applying plasma excitation voltage on the two metal electrodes of the plasma exciters, and generating low-temperature plasma above the metal electrodes embedded in the insulating material; and transferring energy to a boundary layer through the collision of ions and neutral gas molecules to ensure that a horizontal direction jet flow with a static flow of zero is formed by surrounding air so as to accelerate air flows in the boundary layer. The plasma flow control method has the advantages of simple and compact structure, quick reaction, low energy consumption and the like.

The invention discloses an elliptical tube H-shaped fin heat exchanger for waste heat recovery. The elliptical tube H-shaped fin heat exchanger comprises an elliptical heat exchange tube, a plurality of groups of H-shaped fins and a heat exchanger surface, wherein the H-shaped fins are sleeved on the surface of the heat exchange tube; the heat exchanger surface consists of non-uniform triangular small wings, which are elliptically arranged, on the surfaces of the H-shaped fins around the elliptical heat exchange tube. When dusty flue gas flows through the surfaces of the H-shaped fins, the small wings disturb the fluid to enhance the heat exchange on the tube wall and the downstream side, and meanwhile, the deposition of particles on the tube wall is reduced; the pressure drop can be reduced by the elliptical tube while the particle adhesion is reduced. A plurality of longitudinal vortexes are arranged in a non-uniform manner; at the front and rear edges of the wing, the size of the small wings and the windward attack angle are larger; on the middle parts of the H-shaped fins, the size of the small wings and the attack angle are smaller; by using the device, the heat exchange surface in different flow states can be enhanced respectively, the heat exchange of the fins are effectively enhanced, the pressure drop is reduced, and the deposition of dust particles in the flue gas on the heat exchange surface is reduced, so that the heat exchanger can operate efficiently for a long time in the dusty flue gas.

A combined fan-compressor impeller comprises a single hub and a plurality of spaced main blades extending outwardly from the hub such that an air passage channel is defined between two of the main blades. Each of the main blades is a mixed flow blade which continuously extends from a fan section at an inlet end of a channel to a compressor section at an outlet end of the channel without any axial clearance between the fan section and the compressor section, providing aerodynamic matching of pressurized air flowing through the channel from the fan section to the compressor section.

The invention provides an adjustable nozzle comprising an inner cylinder, an outer cylinder, an outer cylinder sleeve and N layers of outer wave structures clamped between the inner cylinder and the outer cylinder; the outer wave structures are radially arranged in sequence along the periphery; gas channels are formed between adjacent outer wave structures, and between the outer wave structures and the inner and outer cylinders; the outer cylinder sleeve is sleeved outside the outer cylinder, and can axially move along the cylinder shaft, thus switching work modes and adjusting flame positions.

The invention relates to a method for exciting and controlling gas flow of the stator blade end wall of an axial-flow compressor by the aid of plasmas, which is characterized by including the steps: laying a plasma pneumatic exciter on the stator blade passage end wall of the axial-flow compressor, wherein the front edge and the tail edge of an electrode of the plasma pneumatic exciter are level to the front edge and the tail edge of a stator blade respectively, and the direction of the electrode is parallel to a mean camber line of the stator blade; when an engine controller detects flow instability indication, loading electric signals to the electrode of the plasma pneumatic exciter by employing a pulse plasma power source; and when the engine controller detects disappearance of flow instability indication, sending out control signals, and closing the plasma pneumatic exciter. The control method is capable of effectively suppressing stator blade angle area flow separation of the axial-flow compressor, short in exciting response time and wide in bandwidth, and has an important role in reduction of stator blade wake pitot loss and improvement on stability and efficiency of the compressor.

An airfoil profile is formed such that a passage width ratio, represented in a dimensionless manner, of an inter-blade passage width of vain root cross-section to an outlet throat width substantially monotonously decreases from a blade inlet toward a blade outlet. The blade has a blade airfoil profile shape in an envelope within a range of ±2.0 mm in a direction normal to any surface location of an airfoil profile portion. The airfoil profile portion has a reference airfoil contour represented in Cartesian coordinates wherein Z is a distance representing a sectional height from a root of the airfoil profile portion. The contours represented by X and Y at each section Z are joined smoothly with one another in a blade height direction to form a complete shape of the airfoil profile portion.

A high-pressure disc thrust gas bearing adopting double symmetrical contraction sections for gas supply comprises an upper working disc (1) and a lower working disc (8) which are arranged in parallel, a gas lubricating film (9) is formed between the upper working disc (1) and the lower working disc (8), and a gas supply component (2) is arranged in the center of the upper working disc (1) and is further connected with an upstream pressure stabilizing cavity. A gas supply hole (3) is formed in the center of the gas supply component (2) and used for introducing gas flow. The double symmetrical contraction sections (4) in a curved surface form are arranged on the downstream of the gas supply hole (3) and are used for smoothly accelerating axial low-speed incoming flow into radial subsonic speed gas flow. According to the high-pressure disc thrust gas bearing, the axial low-speed incoming flow at inlets of the contraction sections is smoothly accelerated into the uniform radial subsonic speed gas flow at outlets of the contraction sections, serious flow separation is avoided at the same time, and the gas flow is further accelerated to the supersonic speed at a gas film outlet. After the gas supply pressure exceeds a certain specific value, the bearing capability of the bearing can be linearly increased along with the increase of the gas supply pressure, and the high-pressure disc thrust gas bearing is suitable for working under high-pressure, heavy-load and large-gap working conditions.

The invention provides a gas compressor stationary blade cascade with an equal-width linear groove formed in a blade root and relates to the passive flow control technology in the technical field of turbomachinery. By means of the gas compressor stationary blade cascade, the equal-width linear groove is formed in the blade root end wall of the gas compressor stationary blade cascade from the pressure face to suction face, and jet flow is formed through detour flow pressure differentials of a blade, so that flow separation is restrained and delayed. The groove is located in the blade root end wall of the gas compressor stationary blade cascade. The spanwise height is a constant value. The inlet of the groove is located in the pressure face of the stationary blade cascade. The outlet of the groove is located in the suction face of the blade cascade. The center line of the groove is a straight line and equidistant from the two side walls of the groove. The gas compressor stationary blade cascade has the beneficial effects that corner separation is restrained; the flow capacity of the blade cascade is increased; the total pressure loss is reduced; the diffusion capacity is improved.

The invention discloses an exhaust steam cylinder of a miniature steam turbine, which comprises a volute and a diffuser, wherein the diffuser comprises an inner deflector and an outer deflector; the volute is arranged on the circumference of the diffuser and comprises an upper wall and a side wall; the width of the volute along the axial direction of the exhaust steam cylinder is bigger than that of the diffuser; the outer deflector is connected with the side wall, and the inner deflector is arranged in the volute; inner wall corners at the connecting part of the upper wall and the side wall and the connecting part of the outer deflector and the side wall are both arc-shaped wall corners; the side face of the inner deflector is a side face consisting of first non-uniform rational spline curves; and the side face of the inner deflector consists of second non-uniform rational spline curves. The exhaust steam cylinder of the miniature steam turbine, provided by the invention, can prevent vortex secondary flow from occurring at the wall corners and eliminate the influence of the vortex secondary flow on steam pressure at the final blade cascade outlet of the miniature steam turbine.

The invention relates to the technical field of turbomachines, in particular to a pit-type compressor blade and a control method for flow separation in a cascade, wherein the compressor blade is provided with a pit. The pit is used as a kind of vortex generator, when the boundary layer fluid flows through the suction surface of the blade, a different form of vortex structure will be formed inside,and the generated vortex will promote the mixing of low-energy and high-entropy fluid and extra-layer fluid in the boundary layer, thereby increasing the kinetic energy level of the boundary layer and suppressing the flow separation, it is mainly used to control the flow separation in a stationary cascade of a compressor and reduce the flow loss, thereby improving the flow condition and the aerodynamic performance of the stationary cascade of the compressor.