18 results about "Critical speed" patented technology

This invention provides a dual-end driven long shaft system multi-order torsional vibration test platform and a torsional vibration identification and suppression method, relating to the field of long shaft system variable frequency drive technology. The platform includes two dual-winding drive motors respectively located at both ends of the shaft system, a load motor located in the middle, and a switchable shaft system connection structure, along with a dual-master, dual-slave cooperative control system composed of four drive frequency converters. This method achieves controllable excitation of multi-order torsional vibration by superimposing the load torque step and the frequency excitation source. It utilizes differential amplification and dual-channel filtering in the signal processing module to extract speed fluctuation characteristics, accurately identifying the critical speeds of each order in the system. For the identified torsional vibration phenomenon, a speed differential negative feedback algorithm is used to correct the torque command of the frequency converter, and the torsional vibration energy of the elastic transmission chain is offset by actively enhancing the system's electrical damping. This invention solves the problem of reproducing complex torsional vibration under safe and controllable conditions and verifying suppression strategies in ultra-large generator units.

This invention discloses a turbine testing apparatus, belonging to the technical field of turbine testing equipment. This apparatus uses a limiting unit between mounting bases. Within the limiting unit, a first directional limiting component and a second directional limiting component are mounted via a bracket. The first directional limiting component limits the connecting lug from a first direction, and the second directional limiting component limits the connecting lug from a second direction. This achieves limiting of the turbine test piece from both directions. After the turbine test piece is installed, the first and second directions are perpendicular to the axial direction of the turbine test piece. By limiting the turbine test piece from the second direction, radial vibration of the turbine test piece can be effectively restricted, reducing vibration during testing, increasing the rotor's critical speed, ensuring successful test completion, and reducing the impact of vibration on measurement results. This ensures accurate final measurement results, provides accurate and effective test data for turbine design, reduces wear on the turbine testing apparatus, lowers maintenance costs, and reduces testing risks.

A flexible membrane disc coupling for super-high-speed cryogenic bearing test and a design method thereof are disclosed. The coupling is coupled with rotors at two ends. Comprehensive design is performed from two aspects of mechanical performance and dynamic performance to ensure that additional load generated by the coupling on bearings of the rotors at two ends is minimum when the coupling is compensated. Through dynamic optimization design, mass and mass distribution characteristics of the coupling are optimized to ensure that critical speed of the whole rotor system meets rigid design principle. Through setting of a heating belt, temperature of a key part of a membrane disc curved surface of the coupling can be ensured to be in an optimal temperature range of a material when the coupling works in super-low temperature. Changes of material performance and space size caused by use of a previous coupling structure in a super-low temperature environment are overcome. The coupling always maintains an optimal working state to ensure compensation and transmission capacity of the coupling when the double-span rotor system operates at high speed.

This invention relates to the field of aerospace propulsion technology and discloses a gas generator circulating liquid rocket engine system with an electric bypass. This invention constructs an electric bypass supply channel by reusing the discharge pipeline, introducing the originally directly discharged high-pressure propellant into the fuel electric pump and oxidizer electric pump for secondary pressurization, and then injecting it into the main thrust chamber via a separately set bypass injector. This solves the problems of traditional open gas generator circulating liquid engines, such as the main turbopump easily entering the critical speed range and causing mechanical resonance under deep throttling conditions, and the deterioration of atomization mixing effect due to insufficient pressure drop of the main injector. It achieves stable operation of the main turbopump within the rated operating speed range and stable high-pressure atomization and combustion of propellant under extremely low thrust conditions, expands the lower limit of the engine's deep throttling capability, and improves propellant energy utilization efficiency and system operational reliability. Simultaneously, the electric bypass supply system enables rapid response and precise adjustment under low thrust conditions.

This invention relates to the field of aero-engine transmission rod design technology, and discloses a method for designing the wall thickness of a variable cross-section transmission rod for aero-engines. By comprehensively considering the maximum speed, power, and structural parameters of the transmission rod under corresponding operating conditions, and utilizing a torsional shear stress model of the transmission rod, the minimum wall thickness parameter that prevents shear fracture of the transmission rod under operating conditions is analyzed in depth. By using the equivalent diameter of the transmission rod and combining it with a critical speed model, the maximum wall thickness parameter that meets the critical speed requirement is accurately calculated. Thus, the range of wall thicknesses for the variable cross-section section of the transmission rod that meets the requirements of torsional shear and critical speed is obtained, enabling rapid design of the transmission rod structure, significantly reducing the iterative calculation time in the design process, improving design efficiency, and providing important support for the rapid and refined design of variable cross-section transmission rods for aero-engines.

This application belongs to the field of engine design technology, specifically relating to a method and apparatus for dynamic balancing design of a high-pressure rotor for aero-engines. The method includes: Step S1, determining the critical speed and rotor mode shape of the rotor based on a rotor dynamics calculation model; Step S2, determining the balance correction surface requiring dynamic balancing design based on the rotor mode shape; Step S3, determining the first unbalanced response of the balance correction surface under different phase combinations at the first critical speed, and determining the second unbalanced response of the balance correction surface under different phase combinations at the second critical speed; Step S4, determining the control range of the phase combinations with the goal that both the first and second unbalanced responses are less than a set value. This application enables controllable design of the unbalanced vibration response of the high-pressure rotor across the entire speed range.

The application discloses a kind of based on intermediary support point strain energy proportion of engine rotor dynamics characteristics improvement method and system, belong to aero-engine and gas turbine rotor dynamics design field.The method includes: S1 establishes coupled double rotor dynamics analysis model;S2 is identified by intermediary support point strain energy proportion greater than first preset threshold and rotor strain energy proportion greater than second preset threshold, high-low pressure coupling vibration critical speed of high pressure rotor excitation;S3 if critical speed does not satisfy speed margin criterion, carries out rotor structure optimization;S4 if still unable to satisfy, set up elastic support structure in intermediary support point, adjust intermediary support point stiffness and optimize strain energy proportion.The application can adjust high-low pressure coupling vibration critical speed to meet margin requirement without changing overall structural layout, and distribute strain energy on intermediary elastic support, reduce the load of intermediary bearing, realize effective protection to it.

This application relates to the technical field of aerodynamic drag reduction, and in particular to a method and system for aerodynamic drag reduction of trains. The method includes: establishing a numerical simulation model of the train's aerodynamic characteristics, simulating and analyzing the turbulent flow field structure around the train, and determining specific flow locations associated with aerodynamic drag reduction; setting up blowing and suction control regions of different ranges at the specific flow locations, and analyzing and determining the active drag reduction control region with drag reduction effect; setting air vents in the active drag reduction control region, performing normal blowing and suction control through the air vents, analyzing and obtaining the variation curve of the aerodynamic drag reduction rate with train speed and blowing and suction control parameters, obtaining the normal blowing and suction mode with drag reduction effect and the critical velocity value based on the variation curve, and establishing a flow velocity control database; and performing active aerodynamic drag reduction control based on the flow velocity control database. This application achieves the effect of accurately determining the active drag reduction control region with drag reduction effect and performing aerodynamic drag reduction control at the required locations.

The present application relates to the field of textile machinery and damping control, specifically to a warp knitting machine high-stability bearing seat and a method thereof; comprising a bearing main frame, a damping energy dissipation core, a leveling support foot, a spherical self-adaptive pad, a monitoring part and a controller; the system obtains top and bottom end vibration data in real time through a sensor, calculates vibration transmission rate and attenuation rate and then solves dynamic stiffness, thereby evaluating damping aging state and calculating resonance critical speed; the core is to densely fill the damping energy dissipation core in the main frame to dissipate periodic excitation energy generated by high-speed operation, and to use spherical contact matching of the hemispherical protrusion at the bottom of the support foot and the hemispherical groove of the spherical self-adaptive pad, so that the support foot can be freely deflected to adaptively compensate uneven ground; the present application solves the problems of insufficient existing foundation stiffness and obvious high-frequency vibration transmission, effectively avoids long-term stress concentration and loose connection of the rack, and greatly improves the support stability.

The utility model provides a kind of high-speed permanent magnet motor belongs to motor design technical field, include: motor shell, inside installation stator assembly, stator winding, rotor assembly, motor rotating shaft and bearing, stator assembly, stator assembly is composed of stator core and stator slot, and stator winding is embedded in the groove bottom position of stator slot.The utility model design structure is reasonable and compact, and the structure of long-tooth stator core and stator slot cooperate groove bottom arrangement stator winding releases radial space, so that bearing is embedded installation, shortens bearing span, improves critical speed and mechanical stability;Axial heat dissipation flow passage design realizes directional cooling while optimizing electromagnetic efficiency, solves permanent magnet demagnetization risk;Solid permanent magnet small shaft diameter embedded structure ensures the strength of rotor at the same time, effectively reduces centrifugal load and wind abrasion loss, improves high-speed operation reliability;Make the high power density of motor and ultrahigh speed in compact space obtain synergistic breakthrough.

This invention discloses an ultra-high-speed longitudinally mounted self-driven sedimentation centrifugal separation system and method, belonging to the field of high-end equipment technology for nanomaterial separation. The system includes a main body, an ultra-high-speed centrifugal drum, an upper magnetic levitation module sleeve, a lower magnetic levitation module sleeve, a vacuum device, an ultra-high-speed spiral groove dry pneumatic sealing system, a centrifugal separation system, and a whole-machine control and sensing network. The upper and lower magnetic levitation module sleeves together constitute the drum's five-degree-of-freedom electromagnetic levitation support and the self-bearing motor direct-drive assembly. The method includes establishing a vacuum sealing condition, accelerating at critical speed avoidance, adaptive tracking of vacuum and gas film pressure speed, deposition quality feedforward compensation, endpoint determination based on stator current identification, and regenerative braking shutdown. This invention eliminates friction and wear and material contamination caused by mechanical contact bearings and couplings, enabling the drum to operate stably at ultra-high speeds and achieve excellent classification accuracy. Adaptive control and energy feedback reduce energy consumption and shorten downtime.

This application provides a torque meter adapter support device, the device comprising: a lower housing; a first mounting portion disposed on one side of the lower housing, the first mounting portion being used to mount one end of the torque meter; a second mounting portion disposed on the other side of the lower housing, the second mounting portion being used to mount the other end of the torque meter; and a torque meter receiving end support seat disposed in the middle of the lower housing, the torque meter receiving end support seat being used to fix the receiving end of the torque meter; wherein, the height of the middle part of the lower housing is less than the height of one side of the lower housing; one side of the lower housing is at the same height as the other side of the lower housing; this invention provides a torque meter adapter support device that, by adding additional support, shortening the support spacing, improving support rigidity, and reducing the length-to-diameter ratio, can reduce the rotational inertia of the high-speed shaft, increase the critical speed, and increase the stability and rotational safety during torque meter measurement.

The application provides a nuclear power plant pipe defect online detection method and system, electromagnetic ultrasonic waves are sent to the cold side pipeline of the nuclear power plant during cooling circulation, echo signals of the cold side pipeline are collected, and a frequency dispersion curve offset feature of the echo signals is determined; a dynamic stability criterion model of the critical speed of steam during gas-liquid flow type conversion is established through the steam flow rate and the frequency dispersion curve offset feature, and a gas-liquid interface instability region in the cold side pipeline is screened out according to the dynamic stability criterion model; flow damping to gas film flow in the cold side pipeline is identified according to the gradient change of the temperature data; the identification boundary of the gas-liquid interface instability region is corrected based on the flow damping, and a defect region of the cold side pipeline under the cold-heat cycle alternating working condition is determined according to the reflection signal of the electromagnetic ultrasonic wave in the corrected gas-liquid interface instability region; the above scheme can correct the oscillation region boundary of the steam in combination with the surface tension distribution, and realize accurate positioning of the pipeline defect under complex working conditions.

The application particularly relates to a nuclear main pump rotor health state prediction method based on digital twinning, and belongs to the field of rotor state monitoring, which comprises the following steps: establishing an initial three-dimensional finite element model according to the actual geometric size and material properties of the rotor; dynamically updating the initial three-dimensional finite element model by using a digital twinning algorithm based on real-time operation data of the rotor, so as to obtain and continuously optimize a digital twinning model; performing fluid-structure-thermal coupling analysis on the updated digital twinning model, and calculating the natural frequency, modal shape of the rotor and the stress time history of the impeller; identifying the critical speed of the rotor and realizing resonance avoidance based on the natural frequency and modal shape of the rotor and the dynamic stress time history of the impeller, and predicting the fatigue life of the rotor impeller. The application realizes accurate prediction of the fatigue life of the nuclear main pump rotor and avoids resonance risk.

The application provides a rotary steering mechanism dynamic balance adjustment method, system and electronic equipment, the method comprises the following steps: obtaining the critical speed of the deflection shaft in the rotary steering mechanism, judging the rotor type of the deflection shaft; performing dynamic balance adjustment on the rigid rotor of the deflection shaft; setting candidate parameters of a balance sleeve used for compensating for the dynamic imbalance of the deflection shaft, the candidate parameters comprising a balance sleeve mass, a mass difference, a geometric parameter and an installation position; collecting vibration response data and motor control data through multi-body dynamics simulation and dynamic balance experiment, and constructing a vibration response database; constructing a proxy model, optimizing the candidate parameters by using a multi-objective optimization algorithm, and obtaining an optimal parameter combination; simulating and experimentally verifying the optimal parameter combination, and outputting the candidate parameters and forming a rotary steering mechanism balance adjustment evaluation report after verification. The application reduces the downhole operation risk, and effectively improves the steering accuracy and the service life of the tool.

The present invention relates to a system and method for throttle table staging warning. In the method of the present invention, a thrust level selection input is first received and a maximum allowable engine speed corresponding to the selected thrust level is determined as an engine target speed based on the selected thrust level, then a throttle lever control command is generated according to the engine target speed so as to determine a throttle lever angle based on the throttle lever control command. A throttle lever command speed is then determined according to the throttle lever angle. Finally, a staging warning determination is made for different aircraft states based on the engine target speed, the throttle lever command speed, the current speed and the critical speed of the aircraft, and a wheel load signal.

This invention discloses a low-pressure rotor dynamics design method based on equivalent vibration length, belonging to the field of aero-engine rotor dynamics. The method includes: determining the minimum bending stiffness section A based on two-dimensional drawings of the low-pressure rotor; dividing the rotor into a disk shaft and blade parts, measuring the disk shaft mass through rotational modeling, and performing equivalent mass calculations for the blades based on overall performance parameters; calculating the equivalent vibration length reduction factor based on the mass distribution, thereby determining the equivalent vibration length L of the low-pressure turbine shaft; calculating the minimum bending resonance speed based on the equivalent vibration length L; considering the high and low pressure rotor speed excitation, determining the critical speed and judging the margin; if not satisfied, adjusting structural parameters for iterative optimization. This invention enables rapid evaluation and optimization of the low-pressure rotor dynamics characteristics based solely on two-dimensional drawings in the early stages of design, bringing the design forward, significantly shortening the iteration cycle, avoiding later design overhauls, and possessing significant engineering application value.

This invention belongs to the field of metal fittings, specifically relating to a high-speed spindle structure and its transmission components. The spindle includes a spindle with one end closed and an eccentrically positioned circular groove at the other end. A rotor and a plug are housed inside the groove, forming a functional cavity between the inner cavity of the groove and the plug. One side of the functional cavity is filled with asphalt, and the other side is filled with water. This invention achieves adaptive vibration reduction across the entire speed range through an eccentrically mounted rotor and dual-medium damping of asphalt and water, effectively suppressing critical speed resonance and fractional harmonic resonance. It also possesses the advantage of temperature-rise self-adjusting damping, meeting the stable operation requirements of high-speed precision machining.