36 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 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 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 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 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 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 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.

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.

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.

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 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.

This invention discloses a dynamic calibration method for the NVH performance of an automotive air conditioning compressor, comprising the following steps: S1, compressor selection and bracket design; S2, setting compressor NVH analysis targets; S4, NVH test simulation benchmarking of the compressor bracket assembly; S5, compressor unit NVH noise test control; S6, setting compressor-wide vehicle noise and vibration targets; S7, compressor-wide vehicle noise and vibration test; S8, compressor-wide vehicle noise and vibration frequency avoidance design; S9, compressor start-stop calibration; S10, optimization of vehicle calibration strategy for environmental chamber simulation test; S11, locking of vehicle calibration strategy for environmental chamber simulation test; S12, determination of compressor verification conditions for high-altitude, high-temperature, and high-humidity tests; S13, optimization of dynamic NVH calibration of compressor for high-altitude, high-humidity, and high-humidity tests; S14, acceptance of dynamic NVH calibration strategy for compressor for high-altitude, high-humidity, and high-humidity tests. The present invention provides a dynamic calibration method for the NVH performance of automotive air conditioning compressors. By combining high-altitude, high-temperature, and high-humidity test data, and by optimizing and adjusting the compressor operating speed at specific speeds and adjusting the compressor transition speed state time control, the method improves the NVH performance of the vehicle air conditioning system without increasing hardware or costs. This achieves a globally optimal balance between air conditioning performance and ride comfort, meeting the development requirements for NVH ride comfort.

The invention relates to a design method suitable for a submersible volute type mixed-flow pump with the specific speed ranging from 400 to 600. The design method comprises two aspects of hydraulic design and structural design, and the hydraulic design comprises the following steps that the bevel angle alpha of an impeller outlet, the included angle epsilon between an impeller rear cover plate and a central axis, the width b2 of the impeller outlet, the diameter D2 of the impeller outlet and the axial length L of the impeller are designed; calculating formulas of the pump body base circle diameter D3 and the pump body inlet width b3, and changing rules of the shape of each section of the pump body and the area of each section are also provided; the structure in the structural design comprises a pump shaft, an impeller, an impeller locking body, a pump body, a pump body sealing ring, a pump cover and a pump cover sealing ring, the impeller is connected with the pump shaft through a flat key, and a mechanical seal for preventing liquid in a rear cavity of the impeller from leaking out of the pump cover is arranged on the pump shaft and located between the pump cover and the impeller. The pump body and the pump cover are connected through a bolt, and a sealing ring is arranged on a contact surface close to the bolt to prevent liquid in a pump cavity from leaking.

The utility model discloses a spiral grading conveying device, the utility model relates to the technical field of conveyer industry technology. This spiral grading conveying device, including power mechanism, gear transmission mechanism, conveying crushing mechanism, grading screening mechanism, unloading mechanism and outside shell mechanism, conveying crushing mechanism and grading screening mechanism all are located inside outside shell mechanism, the unloading mechanism is located outside shell mechanism outside, the unloading mechanism is fixed through the connection technology effect with the lateral surface of grading screening mechanism on the one side of grading screening mechanism outer wall, and the technical effect is through power mechanism, drives gear transmission mechanism, realizes the different specific speed of grading screening device through the adjustment of gear transmission system gear number ratio, and the greater difference of two rotational speeds, the better conveying crushing effect, and the higher smaller particle ratio obtained, the spiral blade can adjust according to the material property, and more material characteristics are adapted, and the function is more, and the cost is lower compared with the same performance.

The application discloses a multi-curvature optimized drag-reducing lateral thruster flow guide groove, and the opening (5) of the lateral thruster (1) is designed in the form of a horn-shaped flow guide groove (6). The application is based on the large-curvature characteristics of a ship line, and according to the water flow direction and the transverse gradient of the opening end, different chamfer angles are designed at different positions, multi-curvature transition and optimization are applied, and a multi-curvature optimized drag-reducing lateral thruster flow guide groove is designed. The application has the advantages that the cutting amount of the structure is reduced, the strength of the structure is retained, and the safety of the structure is ensured. According to the comparison of CFD software, under the specific speed working condition of the actual ship, the flow guide groove of the application reduces the pressure near the side thruster opening, and the overall ship resistance is reduced by 3.2%.

The invention relates to the technical field of gas turbine power generation, in particular to a low-specific-speed centrifugal compressor adaptive to a hydrogen-containing fuel gas turbine power generation system and an optimization method of the low-specific-speed centrifugal compressor. Comprising a meridian flow channel assembly, an impeller and blade assembly and a self-adaptive treatment casing assembly which are coaxially arranged and jointly form a closed pressurized flow field, and the adaptation to a hydrogen-containing fuel gas turbine power generation system is achieved. Through cooperation of the three components, the core pain points that an existing gas compressor is insufficient in stability, low in efficiency and poor in adaptability in a hydrogen-containing fuel system are structurally solved, and an efficient and stable pressurization foundation is provided for a hydrogen-containing fuel gas turbine power generation system.

This invention discloses a hydraulic design method and system for impeller-guide vane coupling matching of high specific speed submersible axial flow pumps, belonging to the field of fluid machinery technology. The method includes the following steps: S1, accurate calculation of impeller diameter; S2, hub ratio graded optimization; S3, blade cascade density collaborative design; S4, blade comprehensive parameter design; S5, guide vane hydraulic quantitative design; S6, dynamic coupling matching of impeller and guide vane. It aims to overcome the inherent defects of existing high specific speed submersible axial flow pump hydraulic design technology, and fundamentally solves the problems of large deviations in actual pump performance and poor adaptability across wide specific speed ranges caused by reliance on model pump similarity conversion in existing technologies. Simultaneously, it addresses the problems of excessive pressure pulsation and insufficient operational stability caused by the lack of impeller-guide vane coupling matching in existing designs, as well as the industry pain points of parameter values ​​lacking systematic theoretical support and the inability to simultaneously achieve high efficiency and cavitation resistance due to empirical design.

The invention provides a dual-channel impeller-double volute structure suitable for an extremely low specific speed centrifugal hydrogen compressor, which comprises a vaneless diffuser, a dual-channel impeller and a double volute, the vaneless diffuser comprises a hub side part and a rim side part, the rim side part comprises an equal thickness section and an expansion section, and the expansion section is connected with the hub side part. The rim side part and the hub side part jointly form a diffuser outlet; the equal-thickness section is closely connected with an outlet of the double-channel impeller, and the outer diameter of the expansion section is gradually expanded in the airflow direction; the double-channel impeller is a closed impeller formed by connecting a hub and a wheel cover through bolts, and airflow flows out through an impeller channel and then enters the vaneless diffuser. The double volutes comprise two centrosymmetric guide assemblies, and each guide assembly comprises a guide section and an air outlet pipe which communicate with each other; and the two guide sections cover the outer edge side of the outlet of the vaneless diffuser. In the implementation mode, the vaneless diffuser achieves adaptation and guiding of complex flow at an outlet of the double-channel centrifugal impeller, the double-channel impeller ensures that effective pneumatic loading capacity is kept under the condition of extremely small flow, and decoupling and efficient guiding of an asymmetric double-channel impeller flow field are achieved through the double volutes.

According to the vibration reduction method of the diesel engine for the double-engine double-propeller ship based on frequency and phase adjustment, the diesel engine for the double-engine double-propeller ship comprises a port engine and a starboard engine which rotate in opposite directions, and a control box of the port engine and a control box of the starboard engine respectively comprise a CAN3 signal control module, an RS485 1 signal control module and an RS485 2 signal control module; the method is characterized in that a control system of the port machine and a control system of the starboard machine are connected in a high-potential and high-potential mode and a low-potential and low-potential mode through a cable, so that beat vibration generated by rotating speed deviation of the port machine and the starboard machine is eliminated; and meanwhile, the port machine and the starboard machine become vibration or torque compensators of each other at certain specific rotating speeds, so that the vibration of a certain order of the port machine and the vibration of a certain order of the starboard machine are mutually counteracted, and the vibration of the diesel engine for the double-engine double-propeller ship and the ship body is reduced. According to the invention, beat vibration is eliminated, and meanwhile, certain-order vibration of the two hosts is counteracted, so that the vibration of the hosts and a ship body is reduced, and the effects of reducing the cost, improving the vibration reduction effect and facilitating operation are achieved.

The invention provides a closed impeller of an extremely-low-specific-speed centrifugal hydrogen compressor and a design method of the closed impeller. The impeller comprises a hub and a wheel cover which are mechanically connected after being machined in a split mode. The wheel cover is provided with a runner, the wheel cover surface is a curved surface, a non-runner area is provided with a weight reduction structure, and reinforcing ribs are reserved; the hub is provided with a segmented annular spigot which is matched with the weight reducing part of the wheel cover to achieve torque transmission and positioning, and the hub and the weight reducing part are provided with protruding sections for sealing. According to the design method, the flow channels are designed by amplifying flow, the number of the flow channels is reduced according to the same multiple, and split machining and assembling are combined. The flow channel height is increased, the machining difficulty and deviation are reduced, the dynamic characteristics and structural rigidity of the rotor are optimized, the operation stability is improved, manufacturing feasibility and flowing performance are both considered, and the rotor is suitable for an extremely-low-specific-speed hydrogen compression scene.

The invention belongs to the field of low specific speed mixed flow water turbine, and discloses a kind of low specific speed mixed flow water turbine runner blade split manufacturing method. The runner is divided into four parts of upper crown blade disc, lower ring inner blade disc, lower ring outer blade disc and short blade casting and processing. Long blade is divided into upper and lower two parts along the rotation cutting surface of the fitting center line of upper crown and lower ring flow channel, and the middle short blade is the remaining part of the short blade after removing the upper crown side short blade root transition step, the lower ring inner ring side short blade root transition step and the lower ring outer ring side short blade root transition step. First, the long blade is welded with radial split welding seam without short blade, then the short blade related welding seam is welded without lower ring outer blade disc, and finally the lower ring outer blade disc is assembled and welded at the runner water inlet edge. The invention can greatly improve the process accessibility of low specific speed mixed flow water turbine runner with small opening, long flow channel and multiple blades, and the design length of short blade flow channel is not limited by the runner manufacturing process, and the blade connection welding seam avoids the high stress area, improving the runner manufacturing quality and operation safety margin.

The invention relates to the field of hydroelectric station pelton turbines, discloses a single-runner pelton turbine diameter ratio calculation method, and solves the problems that in the prior art, a single-runner pelton turbine diameter ratio calculation scheme is inaccurate in calculation, large in deviation from an actual value and low in calculation cost. And the water-power engineering construction requirement of a new device with a single-rotating-wheel water bucket type water-turbine generator set cannot be met. According to the method, data of a large number of well-operated single-runner pelton water turbine generator sets at home and abroad are collected and arranged, and then a complex relation among the data is fitted by adopting a nonlinear regression method, so that a new diameter ratio calculation formula of the single-runner pelton water turbine is obtained; the diameter ratio of the single-runner pelton turbine can be quickly and accurately calculated by substituting the rated specific speed value of a single nozzle of the single-runner pelton turbine with the diameter ratio to be calculated into a new diameter ratio calculation formula of the single-runner pelton turbine.