59 results about "Specific speed" patented technology

The invention discloses a noise reduction method of a bionic fish scale blade centrifugal pump, which comprises the following steps that a long and short blade centrifugal pump is selected for research, and the main design parameters of the long and short blade centrifugal pump are as follows: the specific speed ns is equal to 40.79, the rated flow Qd is equal to 10.6 m < 3 > / h, the lift H is equal to 34m, and the rotating speed n is equal to 2900r / min; a computational domain three-dimensional model of the long and short vane centrifugal pump is established through Creo8.0; in order to prevent backflow of inlet and outlet sections, ensure that fluid stably flows into an impeller and ensure the accuracy of a simulation result, extension pipelines are additionally arranged at an impeller inlet and a volute outlet of the centrifugal pump, the pipe diameter of the inlet extension section is 4 times that of the outlet extension section, and the pipe diameter of the outlet extension section is 8 times that of the inlet extension section; in order to verify the accuracy of a calculation result, a centrifugal pump experiment platform is built for external characteristic experiments; the bionic fish scale pit has the advantages that the dynamic and static interference between the impeller and the volute is reduced, the pressure fluctuation in the pump is stabilized, the amplitude fluctuation of a wave number-frequency spectrum and the energy region of a low wave number region are reduced, the migration of a wave number-frequency spectrum peak ridge is reduced, the curve change is gentle, and then the noise reduction effect is achieved.

The impeller type centrifugal pump suitable for the low-specific-speed working condition comprises a volute and an impeller, the impeller comprises a rotating shaft, a first impeller cover plate, a second impeller cover plate and a plurality of blades, and the first impeller cover plate, the blades and the second impeller cover plate are sequentially and tightly arranged in the axial direction of the rotating shaft. The impeller is arranged in the volute; the volute is provided with a fluid inlet and a fluid outlet; in the axial direction, the distance between the opposite vertical faces of the radial edges of the first impeller cover plate and the second impeller cover plate is smaller than the width of the fluid outlet. And the distance between the opposite vertical surfaces of the radial edges is greater than the width of the fluid outlet. The axial width of the fluid outlet of the centrifugal pump is discussed separately from a general centrifugal pump design theory, so that the design accuracy of the low-specific-speed centrifugal pump is improved, the number of design iterations can be reduced, and the development cost is reduced.

The utility model discloses a viscous damper, belongs to the technical field of dampers, and particularly relates to a variable index protection damper which comprises an outer cylinder, an overflow valve assembly, a piston, a connecting lug seat and a damping medium. The overflow valve assembly is installed in the piston, the piston is installed in the outer cylinder, the number of the connecting lugs is two, the connecting lugs are fixedly connected with the two ends of the outer cylinder respectively, and the damping medium is filled in the outer cylinder; the overflow valve assembly is composed of a sealing gasket, a pressing spring, a locking nut and a pressing steel ball. The overflow valve assembly starts to take effect at a specific speed through a specific spring structure, compared with a previous structure, the production cost and the construction cost are greatly reduced, a so-called protection type damper cannot be effectively protected on site, meanwhile, the index of the damper is a value before the valve is opened, and the safety of the valve is improved. When the set speed is reached, the index of the damper begins to change, and the variable index is achieved.

The invention provides a cold machining manufacturing method of an ultra-fine grain seamless steel pipe. The method comprises the following steps: firstly, selecting a low-alloy structural steel billet with specific components, which comprises C, Si, Mn and microalloy elements of Nb, V and Ti, and heating, perforating and hot-rolling to prepare a pierced billet; and then multi-pass cold deformation treatment is carried out, 5-8 times of cold drawing or cold rolling is carried out on the pierced billet, the deformation of each pass is not lower than 30%, the cold drawing or cold rolling is carried out at the room temperature at the specific speed, and natural cooling is carried out between the passes. Recrystallization annealing is carried out after each pass of cold deformation, heat preservation is carried out for 1-2 hours at the temperature of 650-750 DEG C, and then controlled cooling is carried out. And finally, a finished product is obtained through straightening, head and tail cutting and nondestructive testing. According to the method, through cyclic cooperation of multi-pass cold deformation and recrystallization annealing and the effect of synergistically inhibiting grain growth of microalloy elements, the internal structure of the steel pipe is fully refined and homogenized, and then the comprehensive mechanical properties of the strength and toughness of the finished seamless steel pipe are remarkably improved; and meanwhile, the technological process is stable and controllable, and the product surface quality is excellent.

The utility model relates to the technical field of horizontal mixers, in particular to a horizontal reverse double-helix mixer device which comprises a mixer body, a double-helix mixing mechanism is arranged on the mixer body, the double-helix mixing mechanism comprises fixing plates symmetrically arranged on two sides of the mixer body, a first motor is fixedly mounted on each fixing plate, and a second motor is fixedly mounted on each fixing plate. A spiral shaft extending into the mixer body is mounted at the output end of the first motor; through the arrangement of the double-spiral mixing mechanism, the two oppositely arranged spiral shafts are used for mixing materials in the mixer body to form a movement overlapping area, the movement speed of the materials is higher than that of the materials at other parts, and after the materials are lifted up at a specific speed, the materials can be fully diffused and mixed in the movement process, so that the mixing efficiency is improved. Meanwhile, when the materials are discharged, the materials can be driven by the spiral shaft to be pushed to the discharging opening in the middle from the two sides at the same time, the discharging speed of the materials is increased, and residues of the materials are remarkably reduced.

The present application relates to gas turbine power generation technology field, especially to a kind of low specific speed centrifugal compressor of adaptation hydrogen-containing fuel gas turbine power generation system and its optimization method. Including: meridional flow passage component, impeller and blade assembly, adaptive processing casing assembly, the meridional flow passage component, impeller and blade assembly, adaptive processing casing assembly three maintain coaxial settings, jointly form closed booster flow field, realize the adaptation of hydrogen-containing fuel gas turbine power generation system. Three synergies from structural level solve the core pain points of the stability of existing compressor in hydrogen-containing fuel system, the low efficiency and poor adaptability, provide efficient and stable boost basis for hydrogen-containing fuel gas turbine power generation system.

The invention discloses a method for predicting the performance of a pump turbine in a variable-speed pumped storage project, which adopts a composition analysis method to determine the basic structures of a plurality of correction models, and considers that the turbine performance is closely related to the specific speed thereof under the condition of variable speed. The proportion law is divided into two classes according to the rotating speed ratio, and basic function structures of the two classes are verified respectively. After power and power constructor functions are constructed, the power and the power constructor functions are substituted into the whale optimization algorithm one by one to determine coefficient values of the whale optimization algorithm, and after the coefficient values are determined, optimal correction models, namely a frequency constructor function and a power constructor function, are effectively screened out by comparing R2 values of all the correction models. The method is accurate and fast in calculation and high in calculation precision.

The application relates to a low specific speed double-suction pump vibration reduction and noise reduction design method, a V-shaped structure is arranged at the blade outlet of a double-suction pump impeller, and multiple V-shaped structures are arranged axially along the blade outlet; the low specific speed double-suction pump vibration reduction and noise reduction design method comprises the following steps: step 1, determining a pressure coefficient and a sound pressure level according to numerical simulation; step 2, two-dimensional function fitting according to the pressure coefficient and the sound pressure level data in step 1; step 3, constructing an evaluation function f(h, d) according to the two-dimensional function fitting conclusion in step 2, and obtaining the h and d corresponding to the optimal solution; wherein the distance d at the blade outlet of the impeller is the height h. The V-shaped structure design can effectively reduce the vibration and noise caused by the dynamic and static interference between the impeller and the volute, can effectively control the pressure pulsation of the double-suction pump impeller and the volute, and can determine the V-shaped structure with the best vibration reduction and noise reduction effect through a formula.

The present invention relates to the technical field of pumped storage engineering, and discloses a method for determining the cavitation coefficient of a power station based on a mixed-flow reversible pumped-storage unit. The method comprises the following steps: adjusting a first corresponding relationship between an initial cavitation coefficient and a specific speed to generate a second corresponding relationship; generating a third corresponding relationship based on a determined safety factor parameter and the second corresponding relationship; obtaining first and second power station cavitation coefficient parameters based on the first and second specific speed parameters and the third corresponding relationship; adjusting first and second suction heights generated based on first and second head parameters and the first and second power station cavitation coefficient parameters to obtain third and fourth suction heights; and obtaining first target power station cavitation coefficients and second target power station cavitation coefficients based on the third and fourth suction heights and the first and second head parameters. The present invention determines the power station cavitation coefficient by accurately determining the suction height, thereby improving the accuracy of the power station cavitation coefficient.

The invention relates to the technical field of centrifugal pumps, in particular to an ultra-low specific speed unit transient pressure fluctuation suppression system and method.The method comprises the steps that a segmented broken line type guide vane closing rule is optimized, and decision variables are determined; determining a unit rotating speed water head ratio item in the target function of the multi-target optimization of the guide vane closing rule; according to the method, the'segmented broken line law 'of closing of guide vanes is optimized through a multi-target genetic algorithm, the'rotating speed water head ratio' is taken as a key regulation and control index, transient pressure fluctuation and runner hydraulic thrust are balanced, and the transient pressure fluctuation and the runner hydraulic thrust are controlled. The method is suitable for controlling transition processes such as starting, stopping or sudden load change of an ultralow-specific-speed unit, vibration and noise in the operation process of equipment can be reduced, the service life of the equipment is prolonged, the production efficiency is improved, equipment failures and safety accidents caused by pressure fluctuation are avoided, the production risk is reduced, meanwhile, energy waste is reduced, and the production cost is reduced.

The application provides a horizontal middle-open multi-stage centrifugal pump transition flow channel and a multi-stage centrifugal pump. Two transition flow channels are symmetric along the center of a vortex chamber. The transition flow channel is used for connecting the vortex chamber and a circular cavity in which a next-stage impeller is installed. The transition flow channel comprises a diffusion section which is gradually expanded along the flow direction. The entrance and the exit of the diffusion section are at an acute angle with the horizontal center line, so as to reduce the radial length of the diffusion section. The included angle between the entrance and the exit of the diffusion section and the horizontal center line is not more than 30°. A guide plate is arranged in the transition flow channel at the front of the circular cavity, so as to divide the fluid entering the front of the circular cavity into two flows. The application changes the shape of the outer edge of the transition flow channel to improve the internal flow structure, reduces the hydraulic of the fluid, and achieves the purpose of further improving the head and efficiency of the low specific speed horizontal middle-open multi-stage centrifugal pump.

The utility model relates to a kind of monotonic power type centrifugal impeller of medium-high specific speed and centrifugal pump applying it, solve the problems, such as the characteristic that power cannot present monotone increasing when high specific speed or need additional structure or component to generate high cost of prior art, the technical scheme used includes front cover, back cover, the equal angle distribution of several blades along circumferential direction being set between the front cover and back cover, it is characterized in that the blade is backward-inclined twisted blade, the convex surface of the blade is pressure surface, the concave surface of the blade is non-pressure surface, the water outlet end of the blade is axially inclined arrangement, parallel line parallel to impeller axis is made through the water outlet end surface of the blade, the water outlet end surface of the blade and the parallel line between there is included angle α, 0°≤α≤30°.Its effect: change the shape of blade, so that the impeller of medium-high specific speed presents monotone increasing characteristic, and does not additionally increase external structure or component, can effectively control reasonable cost.

The invention discloses a method for designing blades of a centrifugal cylindrical vane pump. The method comprises the following steps: step 1, calculating a specific speed ns, and judging whether ns is in a range of 20-300 or not; 2, designing an axial plane projection line graph; and thirdly, the blade profile is designed. According to the design method of the blade of the centrifugal cylindrical vane pump, the machining and manufacturing cost is considered while efficient design is achieved, meanwhile, it can be ensured that the pump for a swimming pool can operate under all working conditions without overpower in different time periods and complex operation working condition requirements, and the safety of a motor is ensured.

The double-channel impeller-single volute structure comprises a single volute and a double-channel impeller rotationally connected with the single volute, the double-channel impeller comprises a hub and a wheel cover, and the hub and the wheel cover are machined in a split mode and then mechanically connected to form a closed impeller; a runner is arranged on the wheel cover; a weight reduction structure is arranged in a non-runner area of the wheel cover, and reinforcing ribs are reserved; the hub is provided with segmented annular spigots, and the weight reduction structure of the wheel cover is matched with the segmented annular spigots. The single volute comprises a guide section and an air outlet pipe which are communicated with each other, and the guide section is in a single-circle spiral shape and envelops the periphery of an outlet of the double-channel impeller runner; the section of the guide section is gradually increased; along with rotation of the double-channel impeller, airflow enters the guiding section through the flow channels. According to the embodiment, it is ensured that effective pneumatic loading capacity is kept under the condition of extremely small flow through the two-channel impeller. And the single volute is directly matched with the double-channel impeller, so that the dynamic pressure recovery efficiency of the system is improved, and the volume and the part number of the compressor are reduced.

The application belongs to the technical field of ventilator impellers, and discloses a high specific speed centrifugal ventilator impeller, which comprises a mounting disc, one end outer surface of the mounting disc is fixedly provided with an air inlet cylinder, and the other end of the mounting disc is fixedly provided with a center wheel disc, the outer surface of the mounting disc is provided with an air inlet channel, the outer surface of the center wheel disc is fixedly provided with blades, and the blades are integrally made of nanometer composite materials. The high specific speed centrifugal ventilator impeller is characterized in that the blades are designed in an arc shape, the inner concave side is provided with a flow guide groove and an arc concave angle, and the blades are designed in a variable cross-section, and the cross-section area decreases according to a specific exponential function law, which makes the airflow flow more smoothly on the surface of the blades, effectively reduces the thickness of the airflow boundary layer, reduces the flow resistance, reduces the airflow impact loss, optimizes the airflow flow state, and further significantly improves the energy conversion efficiency. Compared with the traditional impeller, the ventilator can realize greater air volume output under the same power consumption.

The rotational speed of the spray arm is adjusted according to centrifugal force and liquid jets to form a corner nozzle with a variable angle. The regulator includes a counterweight on a pivot and a fluid nozzle. The counterweight has a curved surface to produce a corner nozzle with a variable angle according to the counterweight angle. The centrifugal force generated during rotation pushes the counterweight outwards and increases as the rotational speed of the spray arm increases. The liquid jets are located outside the pivot point and tend to push the counterweight inwards. The thrust of the liquid jets is maximum when the counterweight is most inwards and minimum when the counterweight is most outwards. The regulator stabilizes the arm speed at a specific speed, independent of the friction of the central pivot and the direction tolerance of the nozzle arms of the nozzles. The speed is stabilized when the centrifugal force on the counterweight is equal to the thrust of the liquid jets.

The present application relates to the technical field of fluid machinery, and provides a method and apparatus for hydraulic design of a volute of a feed pump of a mineral slurry preheater, and an electronic device. The method comprises: determining a base circle diameter on the basis of an impeller diameter and a pump specific speed; determining the width of a volute on the basis of an impeller flow passage width, an impeller shroud thickness, and an impeller back vane height; determining the heights of different cross sections on the basis of the area of a cross section VIII and a flow volume of a feed pump, an average flow rate of a medium passing through the cross section VIII, a volute cross‑section top arc radius, and the width of the volute; determining the area of a throat cross section of the volute on the basis of the area of the cross section VIII and the pump specific speed; determining a throat width at a volute tongue cross section on the basis of the area of the throat cross section and the volute cross-section top arc radius; and determining a hydraulic design result of the volute on the basis of the base circle diameter, the heights of different cross sections, and the throat width at the volute tongue cross section. The present application can achieve the purpose of designing parameters of a volute of a feed pump of a mineral slurry preheater, thereby improving the pass rate of one-time volute casting.

The invention belongs to the field of fluid machinery design, and particularly relates to a design method for widening an efficient area of a small-flow low-specific-speed multistage pump, which comprises the following steps of: S1, determining a flow amplification coefficient Kq, a specific-speed amplification coefficient Kns and a reference lift ratio Rb; s2, calculating a lift correction factor Fs based on the specific speed amplification coefficient Kns; s3, calculating a dynamic lift ratio R based on the lift correction factor Fs; s4, calculating a volute section design lift Hvo and a guide vane section design lift Hva based on the dynamic lift ratio R; s5, the design flow Qv of the guide vane section is calculated based on the rated flow Qr; and S6, designing a guide vane and a guide vane section impeller by taking the guide vane section design flow Qv and the guide vane section design lift Hva as basic parameters. The core contradiction of the design of the low-specific-speed multistage pump is solved, the efficiency of a rated point is guaranteed, meanwhile, the efficient area of the low-specific-speed multistage pump is widened, the working range of the multistage pump is widened, and the working stability of the multistage pump in a small-flow area is guaranteed.

The present invention relates to the technical field of impeller structures of low specific speed non-overloading centrifugal pumps, and particularly relates to a composite impeller and a low specific speed non-overloading centrifugal pump, which comprise an impeller rear cover plate and blades. The blades are uniformly arranged on the disk surface of the impeller rear cover plate around its own axis. A forked opening is arranged at a position from 1 / 5 to 1 / 4 of the length from the inlet end to the outlet end of the blade, and the forked opening divides the outlet end of the blade into at least two forked blades; the wrap angle of the blade on the disk surface of the impeller rear cover plate is 150° to 170°, and the outlet angle of the blade on the disk surface of the impeller rear cover plate is 15° to 19°. The present invention can improve the operation performance of the impeller, reduce the casting difficulty of the impeller, reduce the weight of the casting, and reduce the material cost.

The invention is used for the technical field of ventilator impellers, and discloses a high-specific-speed centrifugal ventilator impeller which comprises a mounting disc, an air inlet cylinder is fixedly arranged on the outer surface of one end of the mounting disc, a center wheel disc is fixedly arranged at the other end of the mounting disc, and an air inlet channel is formed in the outer surface of the mounting disc; blades are fixedly arranged on the surface of the outer side of the center wheel disc, and the blades are made of nanocomposite materials in an integrated forming mode. According to the high-specific-speed centrifugal fan, the impeller and the blades are designed in an arc shape, the flow guide grooves and the arc concave angles are formed in the inner concave sides, the variable cross-section design is adopted, and the cross-section area is decreased progressively according to a specific exponential function rule, so that airflow flows on the surfaces of the blades more smoothly, the thickness of an airflow boundary layer is effectively reduced, flowing resistance is reduced, airflow impact loss is reduced, and the service life of the fan is prolonged. The air flow flowing state is optimized, then the energy conversion efficiency is remarkably improved, and compared with a traditional impeller, the ventilator can achieve larger air volume output under the same power consumption.

The application provides a water turbine operation characteristic acquisition method, relates to the technical field of hydropower station design, and determines a quadratic function of a water turbine to be predicted by performing quadratic function fitting on the efficiency and specific speed of the water turbine and constructing a corresponding relationship database of the rated specific speed and the quadratic function, gives different operation water heads and outputs, obtains corresponding efficiency through the expression of the quadratic function of the water turbine to be tested when the operation water head is not less than the rated water head, obtains corresponding flow through a first flow calculation formula, and actual output is equal to the output; when the operation water head is less than the rated water head, the output is updated through an output updating formula, the updated output is obtained, and iteration is stopped until the updated output and the output of the previous time are within a set range; and the water turbine operation characteristic is obtained, the problem that accurate water turbine operation characteristics cannot be obtained in the existing design stage is solved, and the application is suitable for water turbine characteristic acquisition.

The present invention relates to a method and application for designing a non-overload impeller for a low specific speed fire pump, the method comprising: calculating the specific speed when the design point flow, design point head, and speed of the fire pump are known; using the speed coefficient method to design the impeller axial surface, including the impeller inlet diameter, impeller outlet width, impeller outlet diameter, number of blades, and blade inlet edge position; on the determined impeller axial surface, taking the front cover plate, rear cover plate, and intermediate streamlines, and dividing the impeller axial surface into streamline points; determining blade parameters, including blade inlet angle, blade outlet angle, and blade wrap angle; drawing a design streamline grid for the blade working surface and back surface respectively according to the above steps; and determining the throat area of ​​the pump body according to the designed impeller. The present invention more accurately controls the flow state of the liquid flow on the blade surface, makes the flow more closely fit the trend of the blade profile, reduces flow loss, and avoids impact and vortex; meets the requirements of high efficiency and energy saving, and realizes the stable operation of the fire pump without overload.

This invention relates to a self-balancing multistage pump with axial force, solving the problems of high energy consumption, short lifespan, and poor operational stability caused by the large axial force generated by the equal outer diameter of the front and rear cover plates and a specific speed (ns>300) in existing technologies. The technical solution includes a pump body, an impeller string housed within the pump body, and several sets of impeller units within the impeller string. The key feature is that each impeller unit includes a guide shroud, an impeller housed in the guide cavity of the guide shroud, and the impeller comprising a front cover plate, a rear cover plate, and blades disposed between the front and rear cover plates. The outer diameter of the front cover plate is larger than that of the rear cover plate. The front cover plate mates with the bottom of the guide cavity and with the open portion of the guide cavity. Its effects are: by using an impeller with a front cover plate area larger than the rear cover plate area, and in conjunction with the guide shroud, self-balancing of the impeller axial force is achieved, making the pump operation more stable and reliable, significantly reducing power consumption, greatly improving social and economic benefits, and achieving the goal of energy conservation and emission reduction.

Belt webbing receiving device (10) comprising: a take-up shaft (20) capable of receiving a webbing (22) worn by an occupant, which is rotated in a take-up direction (A) to receive the webbing (22) and which is rotated in a pull-out direction (B) by pulling out the webbing (22); a rotating body (38) capable of rotating in accordance with rotation of the take-up shaft (20); a limiting member (26) that limits rotation of the take-up shaft (20) in the pull-out direction (B) by the limiting member (26) by causing it to be operated; an operating member (44) provided on the rotating body (38) and displaced to cause operation of the limiting member (26) when the rotating body (38) is rotated in the pulling-out direction (B) at a specific speed or higher; and a limiting body (66) which is moved to an admission position which permits a displacement of the operating component (44) when the rotating body (38) is rotated in the withdrawal direction (B), and which is moved to a limiting position which allows the operating component (44) to abut against the limiting body (66) when the rotating body (38) is rotated in the receiving direction (A), wherein the limiting body (66) limits the displacement of the operating component (44) by the abutment of the operating component (44) against the limiting body (66), wherein a contact angle (θ) of the limiting body (66) and the operating component (44) is set at 90° or greater, and wherein a strength of the operating member (44) at a location located on a limiting body side is set lower than a strength of the operating member (44) at a location farther away from the limiting body (66) than the location located on the limiting body side of the operating member (44).

The invention provides a plug-in hybrid-driven gasoline engine starter, which relates to the technical field of gasoline engine starting systems and comprises an outer shell, a one-way speed reducer, a motor, an energy storage device, a release device, a protection device, a starting gear and a connecting sleeve. The device has the advantages of being reasonable and simple in structure, low in production cost, convenient to install and complete in function, the overall design gives consideration to practicability and economical efficiency, and large-scale production and assembly and use in actual application scenes are facilitated; stable speed reduction transmission of power is achieved through a specific speed reduction transmission structure, the one-way transmission matching design is matched, it can be ensured that the power is only transmitted in the preset direction, interference and damage of reverse force to internal transmission parts are effectively avoided, and the reliability of power transmission is improved; the energy storage mechanism is adopted to store elastic potential energy, quick release of power is achieved through triggering of the release mechanism, sufficient and stable power can be provided for starting of the gasoline engine, and it is guaranteed that the starting process is smooth and efficient.

The utility model relates to the technical field of keyway detection tools, and provides a motor shaft keyway symmetry degree detection tool for solving the problems of inconvenience in operation and low detection efficiency in the conventional workpiece keyway symmetry degree measurement process, which comprises a detection ring which can be sleeved on the outer side wall of a motor shaft. The outer side wall of the motor shaft abuts against the inner side wall of the detection ring. The detection ring is provided with a base and a movable frame arranged on the surface of the base, the detection ring is movably connected with the movable frame, and the detection ring can reciprocate along a straight line. According to the motor shaft keyway symmetry degree detection tool, whether the size of the side wall surface, the symmetry degree and the like of the motor shaft to be detected meet the requirements or not is judged by observing whether the detection ring can smoothly move along the linear direction or the specific speed of falling to different heights or not in the falling process, the operation is convenient, and the detection efficiency is high.

To achieve a reduction in the load on a rear stage side compression part.SOLUTION: A centrifugal compressor 10 includes five-or-more-stage compression parts 11, 14, a bull gear 19, and pinion shafts 21, 22. An outer diameter of the pinion shaft which drives the final stage compression part is smaller than an outer diameter of the pinion shaft 21 which drives the first stage compression part 11, and an outer diameter of an impeller of the final stage compression part is smaller than an outer diameter of an impeller 11a of the first stage compression part 11. A peripheral velocity Mach number of the impeller 11a is 1 to 1.5 both inclusive, and specific speed is 400 to 450 both inclusive. The peripheral velocity Mach number of the impeller of the final stage compression part is 0.5 inclusive to 1 exclusive, and the specific speed is 150 to 350 both inclusive.SELECTED DRAWING: Figure 1

The utility model discloses a sectional type multi-stage centrifugal pump with a double-suction impeller layout, which relates to the technical field of water pumps and comprises a main shaft and a pump body, and two ends of the main shaft are connected with the pump body through bearings. The pump body comprises a water inlet section, water pumping sections and a water outlet section, double-suction impellers arranged on the main shaft in a sleeving mode are arranged in the water inlet section, the water pumping sections and the water outlet section, a water inlet is formed in one end of the water inlet section, and the other end of the water inlet section is connected with the water pumping sections through flow guide pipes. One end of the water outlet section is connected with the water pumping section through a flow guide pipe; the effective sealing surface between high pressure and low pressure is long, and the leakage rate is very small; the impeller is wide in runner, large in design flow and capable of adapting to various complex working conditions; the specific speed and the efficiency are high; due to double suction inlets, the net positive suction head NPSHr is low, and the effective suction stroke is high; a balancing device or a throttling device is reduced, the efficiency is improved, and the service life is prolonged.

The invention discloses a vertical vibration reduction method and device for a railway vehicle, a whole train, equipment and a medium, and relates to the technical field of computers. The method is applied to the vibration reduction system, the system comprises at least one centrifugal actuator, the centrifugal actuator is installed on a target component, the target component is a component located on the railway vehicle and affected by vertical vibration of a vehicle body, and the method comprises the steps that band-pass filtering is conducted on the initial vertical vibration acceleration of the target component, and the target vertical vibration acceleration is obtained; determining a phase angle of each motor in the centrifugal actuator according to a damping force obtained by calculating the target vertical vibration acceleration; the motors are controlled to operate according to the corresponding phase angles so as to drive eccentric mass blocks in the centrifugal actuators to generate centrifugal resultant force, and therefore vertical vibration reduction of the railway vehicle is achieved. The problem that violent vibration on a specific speed section cannot be eliminated is solved, improvement of overall vibration of the vehicle body is achieved, and the problems that broadband vibration control is difficult to achieve and application flexibility is poor in a traditional scheme are solved.

This invention relates to a method for analyzing the resistance components of a waterjet-propelled ship model. First, a resistance test is conducted on the bare hull. Next, a self-propelled test is performed to determine the rotational speed of the waterjet propulsion device at a given self-propelled point. Then, an L-shaped nozzle is installed, and the waterjet propulsion device operates at the self-propelled point rotational speed at a specific speed, measuring the total hull resistance. Simultaneously, the flow field in the flow region is measured using PIV technology, and the inlet longitudinal momentum is calculated. Finally, the total resistance is subtracted from the bare hull resistance and the inlet longitudinal momentum to obtain the impact of the propeller operation on the hull resistance at the corresponding self-propelled point. This invention employs conventional resistance tests, L-shaped nozzle resistance tests, self-propelled tests, and flow field measurements in the flow region to decompose the resistance into the hull's own resistance components and the hull resistance increment caused by the suction effect of the waterjet propulsion device. This allows for the identification of the propeller's impact on the hull, reducing hull shape optimization to a single objective function optimization problem and improving hull shape optimization efficiency.