492 results about "Cavitation erosion" patented technology

The invention discloses an optimization design method of an impellor for a cavitation-erosion-resistant centrifugal fan. The method is characterized by acquiring a front cover plate two-dimensional airfoil epiphyseal line, an intermediate two-dimensional airfoil epiphyseal line and a rear cover plate two-dimensional airfoil epiphyseal line on a circumferential XY plane of an original impellor; constructing impellor optimization parameters after parameterization, and constructing an epiphyseal line after variation; inputting the front cover plate two-dimensional airfoil epiphyseal line, the intermediate two-dimensional airfoil epiphyseal line and the rear cover plate two-dimensional airfoil epiphyseal line which are acquired through three dimension variation into a geometric modeling software, thus an impellor three-dimensional shape after variation is formed; measuring and calculating water conservation performances on the basis of single channel meshing; taking a non-dominated sorting genetic algorithm (NSGA-II) of a multi-objective genetic algorithm as an optimization tool, and carrying out multi objective optimization design on the impellor parameters of the centrifugal fan; and selecting a group of impellor parameters with optimal water conservation performance as the impellor parameter after optimization. The method provided by the invention has scientific construction ofoptimization parameters, the optimization process has high automatic degree, the impellor and blade efficiency of the centrifugal pump is high after optimization, and the cavitation erosion performance is outstanding.

The present invention provides corrosion inhibition formulations and compositions for inhibiting mineral scale and the corrosion of metals particularly the cavitation corrosion of aluminum in the presence of aqueous liquids. The combination of a mixture of polymeric polycarboxylates, azoles, nitrate salts, phosphates, stabilized silicates and transition metal compounds provide a synergistic protective effect against the cavitation corrosion of aluminum in aqueous liquids reducing the corrosion rate and is effective at relatively low concentrations and varying pH ranges. The addition of selected polymeric polycarboxylates not only significantly reduces glycol based coolant cavitation erosion-corrosion, heat rejecting aluminum corrosion, and hard water precipitates and scale, it has been discovered that polymeric polycarboxylates in combination with siloxane stabilized silicates enhance secondary silicate stabilization leading to improvement in aluminum corrosion protection and coolant life when utilized with selected amounts of the above-identified additives. The formulations are particularly suitable for automotive applications.

The invention discloses a gyrating drilled shaft provided with an aeration ridge. The invention is characterized in that the gyrating drilled shaft is provided with an aeration ridge on the wall surface at the middle lower part of the drilled shaft section, the aeration ridge is formed by gradually shrinking the drilled shaft connected with the upper flat section of a flood discharging tunnel from the middle part to the middle lower part and then suddenly expanding the wall surface, and at least two aeration holes are distributed on the annular aeration ridge formed by the sudden expansion, each of the aeration holes is spliced with a vent pipe communicating with the atmosphere. The vent pipes can be selectively buried on the outer side of the gyrating drilled shaft. The gyrating drilled shaft disclosed by the invention enables near-wall water layers at the lower reaches of the aeration ridge to become into aerated water flows, thereby increasing the flow cavitation number, playing the effects of air entrainment and cavitation prevention, preventing the overflowing section at the middle lower part of the drilled shaft from being damaged by cavitation erosion, and ensuring the safe flood discharging operation of the gyrating drilled shaft.

The invention discloses a cavitation erosion-erosion wearing cooperative test device. A slurry tank inlet is formed by a convergence of three branches which are a gas inlet, a water inlet, and a solid particle inlet. A transmission shaft of a motor extends into the slurry tank, and drives stirring blades to rotate. The outlet of the slurry tank is connected to an inlet of a separator through a stop valve and a cavitation erosion-erosion wearing test valve, and a pipeline. A gas phase outlet is provided on the top of the separator. A solid-liquid double-phase outflow port on the bottom of the separator communicates with a recovery tank. A liquid level gauge and pressure gauge are arranged on the side of the slurry tank. With the device provided by the invention, the flow state of a multiphase flow medium can be observed, and particle motion trajectory can be observed. With a valve core pressure sensor on the top of the test valve core, the determination of flow cavitation number is realized. The device is suitable to be used for researching cavitation erosion and erosion wearing, and weight loss law of a metal material under the cooperative effect of cavitation erosion-erosion under different influencing facts. With the device, a functional relationship between a corresponding failure mode and weight loss can be established. The relationship can be used in guiding design of pipes, valves, and pipe fittings, and in optimization operations of operation conditions.

The present invention relates to flood discharge method and flood discharge tunnel dissipating energy by means of eddying flow and intense water-air mixing, and is especially one flood discharge tunnel for high water head large hydraulic power project. The flood discharge tunnel includes one water inlet in the upstream of dam, one eddy flow and fall head energy dissipating facility connected to the water inlet and provided with well, one water cushion pond with one waterproofing pier in the exit for further energy dissipating, one water output tunnel connected to the water cushion pond and one water outlet. The flood discharge tunnel has one energy dissipating rate as high as 90 %, and can control the outlet flow rate and prevent cavitation erosion, scouring and atomizing effectively.

An in-line monitor method and diagnosing apparatus for the damage of cavitation and cavitation erosion of hydraulic machinery is characterized by that the cavitation coefficient, pressure pulse, energy characteristics of hydraulic machinery, working water head, and the cavitation impact signals are measured, the lost metal weight is calculated out and the intensity of cavitation and cavitation erosion and damaged legree are analyzed.

The invention discloses a laser shock method. The method comprises the following steps: (A) providing a laser shock device and a vacuum ion plating machine, wherein the laser shock device comprises a computer control system, a high-power laser, an automatic water sprayer and a worktable, the worktable is equipped with a first fixture and the vacuum ion plating machine is equipped with a second fixture; (B) covering an aluminum foil absorbing layer on the surface of a metal material; (C) controlling the automatic water sprayer to spray water to the surface of the aluminum foil absorbing layer by means of the computer control system; (D) controlling the worktable to move by means of the computer control system; (E) controlling the high-power laser to emit laser beams to the aluminum foil absorbing layer by means of the computer control system; and (F) finally removing the aluminum foil absorbing layer, placing the metal material in the vacuum ion plating machine and forming a graphite coating on the surface of the metal material by utilizing a physical vapor deposition method. By utilizing the laser shock method, surface strength and hardness of the metal material can be improved and cavitation erosion can be effectively avoided.

The invention belongs to a multifunctional submerged jet type cavitation test device in the fields of cavitation erosion resistance and erosion corrosion resistance of metal materials, a detachable upper end cover arranged closely is provided on top of a tank, a pressure valve and a pressure release valve are arranged on a side wall of the sealed tank, a nozzle is detachably arranged on an inner end of the tank of the same tube of the pressure valve, a testing bracket and a testing sample wafer are arranged on the other side wall of the sealed tank, a plug screw and a traverse education through hole for testing thereon are arranged at a lower part of the same side wall of the sealed tank and the pressure valve, the traverse and the education through hole are sealed through sealant; a pressure gauge is arranged on an upper part of the sealable tank matching with the pressure release valve; the plug screw and the sealed tank are sealed through a seal ring. The device is reliable in structure theory, low in manufacturing cost, handy in working use, precise in experiment effect, long in service life and reduced in energy consumption.

The invention provides a design method for an axial flow impeller machine for confirming the flow model of the axial flow impeller machine. The method at least includes the circle component of vu2 and axial plane speed of vm2 which are at the exit of a vane and are distributed in a way of linearity along the radius of the vane, and the circle component and axial plane at the hub side is small while the circle component and axial plane at the wheel edge side is larger; the distribution functions of the circle component vu2 and axial plane speed vm2 at the exit of the vane are confirmed according to the external characteristic parameters and structure parameters as well as the flow model of the axial flow impeller machine; the axial flow impeller machine is designed according to the confirmed distribution functions of the circle component vu2 and axial plane speed vm2 at the exit of the vane. The invention also provides the vane of the designed axial flow impeller machine; wherein, the difference of the mounting angles for the wing models of the hub side and wheel edge side of the vane Delta Beta is equal to Beta h minus Beta s and is between minus 3 degrees to 10 degrees. The equipressure area at the back of the vane is distributed along the radial direction of the vane in strip. The invention can improve the efficiency of the impeller machine to reach 91 percent and improve the anti-cavitation erosion capacity.

The invention discloses a whole section aeration method of a flood discharging tunnel. The bottom part of a free flow flood discharging tunnel is provided with a backward step and a ventilation shaft, which form bottom cavity aeration, based on which a lateral deflector is respectively arranged at side walls on two sides of the upstream of aeration backward step, therefore, an aeration side cavity is formed and the whole section aeration is further formed at the aeration backward step. The deflector inside the flood discharging tunnel with the whole section aeration structure designed according the method is a wedge deflector. Since the whole section aeration changes the former simplex method of bottom cavity aeration and guarantees the necessary aeration quantity when the flood discharging tunnel in normal operation, thus eliminating large-area fresh water flooding district at the side walls of the flood discharging tunnel and effectively avoiding the cavitation eroding damage of the side walls.

A high-pressure fuel injection pipe having connecting head portion is provided which is capable of eliminating a fear of the occurrence of cavitation erosion of the inner surface of the connecting head portion and a fatigue failure of the same head portion by having a contour of a cross section of an annular pocket occurring in an inner part of the connecting head portion during a head portion processing operation extend shallowly and gently. This fuel injection pipe has at a connecting end portion of a thick-walled steel pipe having a relatively small diameter, including a seat surface, an annular flange formed so that the flange is axially spaced from the seat surface, and a conical surface connected to the seat surface, extending therefrom to the annular flange and tapering off to a free end of the connecting head portion, wherein the conical surface is provided at a part thereof with an annular, shallow, cross-sectionally curved recess.

The invention discloses cavitation erosion test equipment for testing material performance and a test method thereof, wherein the equipment comprises a Venturi tube, a water tank, a centrifugal pump, a pipe system, a pressure meter A, a pressure meter B, a flow meter, a flow regulation valve A, a flow regulation valve B and a flow regulation valve C, wherein the front end of the Venturi tube is respectively connected with the pressure meter A, the flow regulation valve A, the flow meter, the centrifugal pump and the water tank through the pipe system in sequence; and the rear end of the Venturi tube is respectively connected with the pressure meter B, the flow regulation valve B and the water tank through the pipe system in sequence. The flow regulation valve A and the flow regulation valve B are regulated so that an inlet end and an outlet end of the Venturi tube has a certain pressure difference, and cavitation phenomena occur at the tail end of the neck part of the Venturi tube and the front part of an outlet taper angle. The test method is closer to the generating process of the cavitation erosion in fluid under the actual working conditions. The equipment disclosed by the invention needs few workpieces and has low cost, simple operation process and stable performance in the cavitation test.

The invention discloses a device and a method for polishing a symmetrical optical component of a small-caliber rotating shaft. The device comprises a sealed container mechanism, a workbench drive system which is installed in an inner cavity of the sealed container mechanism and a polishing fluid circulating system which is connected with the sealed container mechanism; and a negative pressure space is formed in the upper part of the inner cavity of the sealed container mechanism. During the polishing, a suction effect of negative pressure difference is utilized for sucking and compositing polishing fluid, a negative pressure cavitation effect is utilized for machining a workpiece surface, a normal pressure environment of machining is changed into a negative pressure environment, air disturbance in an injection process is reduced, a polishing point can be reduced, and the sliding friction function and stability of micro and fine abrasive particles are increased; and moreover, the negative pressure cavitation effect forms strong cavitation shock wave and high speed micro jet, so that the removal efficiency of the workpiece surface is increased. Materials are removed under the combined action of abrasive particle cutting and cavitation erosion, so that the surface with high quality is obtained. The device is suitable for polishing various rotating symmetroid optical components, and has a high practicable value in automatic processing.

The invention discloses a visualized testing device for cavitation-cavitation erosion relation measurement. The device comprises a fuel oil supply system, a reaction system and a measurement system, the fuel oil supply system comprises a fuel tank, a heating device, a diesel filter, a pump station, an oil pressure adjusting valve, an adjustable butterfly valve, a buffer section, a compressor and a vacuum pump; the reaction system comprises a test section and a metal foil piece; the measurement system comprises a pressure sensor, a flow sensor, a signal control terminal and a computer. The visualized testing device has the advantages that the structure is simple, the device runs stably, cavitation erosion intensity is continuously adjustable, test operation is simple, the induced cavitation performance effect of the test section is good, and the generation areas of vacuole clusters adjacent to the test section and cavitation erosion characteristics on the metal foil piece are easy to observe.

The invention provides a cavitation-erosion-preventing novel double-fuel injector and a common-rail fuel system. The cavitation-erosion-preventing novel double-fuel injector comprises an injector body and an electromagnetic control device. The injector body comprises a needle valve arranged in an injector body axis piston cavity, a second reset spring arranged on the needle valve in a sleeving manner, a first fuel guiding device and a second fuel guiding device, wherein the first fuel guiding device and the second fuel guiding device are arranged at the two ends of the tail of the injector body. The electromagnetic control device is assembled at the tail of the injector body. A cable, a first reset spring, an armature and an electromagnetic valve are arranged in the electromagnetic control device. A common rail fuel system is connected with the two fuel guiding devices of the injector through two fuel high-pressure common-rail pipes to send fuel to the injector. The cavitation-erosion-preventing novel double-fuel injector and the common-rail fuel system are used for achieving in-cylinder direct injection of two different kinds of fuel, and the problem about in-cylinder direct injection of a diesel induced ignition natural gas engine is solved; and the nozzle structure is optimized, and the problem of insufficient lubrication existing in the gas fuel injection process is effectively solved through lubricating injection holes.

The invention discloses a cavitation erosion detection method based on acoustic emission, which comprises the following steps: utilizing an acoustic emission sensor to collect an acoustic emission signal in unit time length during cavitation erosion development; performing wavelet decomposition on the acoustic emission signal according to set layer number to obtain a wavelet coefficient and relevant degree of the cavitation erosion and frequency range where the wavelet coefficient is located, and denoising the wavelet coefficient according to the relevant degree and the set layer number; performing signal reconstruction by utilizing the wavelet coefficient after denoising, and obtaining a reconstruction signal; setting parameter estimating threshold and counting time interval of the reconstruction signal; calculating acoustic emission event number and acoustic emission even average energy of the reconstruction signal; and judging plastic deformation and mass loss condition during cavitation erosion development according to the acoustic emission even number and the acoustic emission even average energy. The cavitation erosion detection method based on the acoustic emission performs denoising according to the characteristics of the acoustic emission signal and utilizes a simple estimating parameter to represent the development condition of plastic deformation and mass loss during cavitation erosion.

The invention relates to a rotating scaling type abrasion-cavitation erosion coupling test method and device. The test method comprises the following steps: manufacturing the inner edge of a tested piece into a bulge, placing the bulge in a sealed abrasion-cavitation erosion chamber and forming a scaling type flow channel by matching the bulge with a rotating impeller in the abrasion-cavitation erosion chamber; filling water flows containing sands; starting a rotating driving motor and a water circulating pump, spraying the water flows containing sands from a hollow blade and rotating and flowing at a high speed; forming rushing-abrasion damage and cavitation erosion damage to the surface of a concrete tested piece; after testing, taking out and weighting the tested piece and measuring anabrasion depth; and discharging the water flows containing sands. The abrasion-cavitation erosion coupling test device is provided with the abrasion-cavitation erosion chamber, wherein a rotating water-sand spraying impeller with a hollow structure is arranged in the abrasion-cavitation erosion chamber; the bulge of the inner edge of the tested piece is matched with the rotating impeller; and thescaling type flow channel is formed in the abrasion-cavitation erosion chamber. The test method and device can be used for testing the abrasion-cavitation erosion resisting capability of concretes under the abrasion-cavitation erosion coupling action of the high-speed water flows containing sands and have the advantages that the maximum flow speed reaches 40m/s-60m/s, the occupied area is small, the rushing-abrasion efficiency is high, the energy conservation and environmental friendliness are realized.

The invention discloses a discharge chute which comprises a bottom plate and side walls at two sides of the bottom plate, wherein the bottom plate comprises a plurality of stepped bottom plates and a plurality of smooth bottom plates; the stepped bottom plates and the smooth bottom plates are alternately arranged; and a plurality of convex bodies are arranged on the smooth bottom plates and/or the side walls. According to the discharge chute, the convex bodies are arranged on the smooth bottom plates and/or the side walls, so that the roughness of the discharge chute is improved, the frictional resistance is increased, the turbulent energy dissipation rate is improved, a mass of water flow energy is dissipated, the risks of the cavitation erosion destroy of the discharge chute and the erosion destroy are reduced and the flood discharge safety is improved.

The invention relates to a multi-modal regression analysis based hydroelectric generating set's cavitation erosion signal feature extraction method, which comprises the following steps: 1) obtaining the cavitation erosion signal measuring data from a monitoring system; 2) establishing variation modal decomposition (VMD) parameters and decomposing the cavitation erosion signal into a series of modal components; 3) carrying out multivariate autoregressive modeling to all components; and using the Bayesian criterion to determine the order of the model; 4) constructing the model parameters identified by the QR decomposition method for the initial feature of the cavitation signal; and 5) using the principal component analysis to extract the main element for the final signal characteristics. The technical scheme of the invention realizes the adaptive separation of the intrinsic mode of the cavitation signal, and the characteristic vector obtained by the multimodal regression analysis embodies the important information of the system state, and realizes the full representation of the cavitation signal.

The object of the invention is to provide a fuel injection nozzle with which occurrence of cavitation erosion due to occurrence of separation of fuel flow near the needle valve and injection holes is suppressed and variation in fuel injection characteristic is reduced, a method of machining injection holes, and an apparatus therefore to attain the object. An insert tool shaped like the needle valve or an insert tool having a conical surface similar to the needle valve and a groove or grooves are on the conical surface to introduce abrasive fluid to the injection holes, is inserted in the central hollow of the nozzle body when performing abrasive fluid flowing processing to round entrance corners of the injection holes, and the processing of each of the injection holes is stopped when flow rate of abrasive fluid flowing out through relevant injection hole reaches a predetermined value.