181 results about "Critical speed" patented technology

According to the bearing rigidity optimization and vibration reduction design method for the rotor and the bearing system, under the condition that the structural form of the rotor and the bearing system is not subversively adjusted, the elastic bearing and the extrusion oil film damper are arranged and designed, and the bearing rigidity of the rotor and the bearing system is optimized. The fulcrum rigidity is reduced to change the strain energy distribution of the rotor and adjust the critical rotating speed, and the vibration level of the rotor, especially vibration caused by sudden unbalance and transcritical of the multi-fulcrum rotor, is suppressed.

The invention relates to an optimization design method for a multi-fulcrum elastic ring supporting structure of an aero-engine rotor system, and belongs to the technical field of aero-engine vibration control and rotor dynamics simulation. Firstly, a finite element or lumped unit model is adopted to establish a coupling kinetic equation of a rotor and an elastic ring, and fluid-solid coupling factors such as inner and outer oil films of the elastic ring and orifice flow are considered; then, through critical rotating speed and vibration harmonic response analysis, sensitivity evaluation is carried out on rigidity and damping characteristics of different supporting positions, and target vibration reduction modes corresponding to all fulcrums are identified; then, coupling simulation and multi-objective optimization are carried out around the number of bosses of the elastic ring, the height of the bosses, the damping aperture, the thickness of a thin wall and other key structure parameters, and the optimal design meeting the vibration reduction requirement of a rotor system and the strength reliability requirement of the elastic ring is obtained through iteration; and finally, an optimization result is applied to structure manufacturing and assembling. The method can effectively reduce the vibration amplitude of the rotor when the rotor crosses the multi-order critical rotating speed.

The present invention relates to a five-degree-of-freedom ultra-high-speed bearingless permanent magnet motor. Both ends of a cylindrical solid permanent magnet are respectively connected to a rotating shaft. A casing is installed outside the cylindrical solid permanent magnet. A stator core is fixedly installed on the casing. A set of torque windings is embedded in the bottom layer of the stator core, and two sets of suspension windings are embedded in the upper layer of the stator core. End covers are fixedly installed on both sides of the casing. Auxiliary bearings are installed between the end covers and the rotating shaft. Passive permanent magnet bearings are nested on both the end covers and the rotating shaft. The present invention is reasonably designed, integrating a magnetic suspension bearing and a permanent magnet motor into one. While the motor generates an electromagnetic torque capable of driving the rotor to rotate, it can also generate a radial suspension force to overcome the rotor gravity and unilateral magnetic pull force, simplifying the motor structure and shortening the axial length of the motor. The double suspension windings and the axial passive permanent magnet magnetic bearing achieve five-degree-of-freedom control, increasing the rotor stiffness and critical speed of the ultra-high-speed motor, and improving the operation stability and anti-disturbance ability.

The invention relates to the technical field of vibration active control and artificial intelligence, and discloses an aero-engine fan rotor keyless phase virtual dynamic balance method and system based on a finite element method, and the system comprises a modeling and simulation module which is configured to obtain the first-order critical speed and vibration mode of an initial rotor dynamics simulation model; the model calibration module is configured to calibrate the initial rotor dynamics simulation model according to the first actual amplitude to obtain a calibrated rotor dynamics simulation model; the model updating module is configured to update the calibration rotor dynamics simulation model to obtain an updated rotor dynamics simulation model; and the trial weight and counterweight module is configured to substitute the second actual amplitude into particle swarm optimization, calculate the actual total unbalance amount of the rotor system and the trial weight angle difference, and finally add a counterweight and select a direction until the vibration is reduced to realize dynamic balance. According to the invention, the position of the unbalance can be accurately determined only through amplitude analysis.

The invention discloses a magnetic bearing rotor state monitoring device based on a flexible detection lantern ring. The rotor motion state monitoring device is composed of a magnetic suspension bearing system, the flexible detection lantern ring, an emitting electrode iron core, an emitting coil, a support, frequency sweeping equipment and the like. A rotor of the magnetic suspension bearing system is sleeved with a flexible detection lantern ring, a PI flexible material is used as a base layer of the flexible detection lantern ring, a temperature sensor, an acceleration sensor and a strain sensor are arranged in the flexible detection lantern ring to collect data so as to measure data of strain, torsion, amplitude and temperature of the rotor, and the flexible detection lantern ring is charged by adopting a wireless charging technology. And finally, sensor signals are transmitted at different frequencies through an oscillating circuit and an antenna accessory circuit in the sensor matching circuit, and are transmitted to frequency sweeping equipment for frequency sweeping receiving processing. The device solves the problem that related important data of a rotor mode cannot be directly measured in real time, so that a control strategy is changed immediately when the rotor reaches a critical rotating speed, and stable operation of a magnetic bearing system is maintained.

The invention relates to the technical field of aero-engines, in particular to a boss structure optimization method for an elastic ring type squeeze film damper, which comprises the following steps: acquiring an oil film gap of the damper; corresponding circumferential relative oil film force and radial relative oil film force of the damper under different eccentric ratios are obtained; obtaining multiple groups of optimization parameters; constructing a constraint function and a target function; and obtaining an optimal optimization parameter, and obtaining an optimized boss structure. According to the optimization method, the influence of the boss height and the boss width on the circumferential relative oil film force and the radial relative oil film force is considered, and the purposes of improving the circumferential relative oil film force of the damper and reducing the radial relative oil film force of the damper are taken as targets, so that the optimized boss structure can increase the oil film damping, enhance the vibration reduction characteristic and reduce the oil film rigidity; and the influence of the damper additional rigidity on the critical rotating speed is weakened.

The invention discloses a method for calibrating a contact track radius of a test disc in a ball disc type dragging force test. The method comprises the following steps: measuring and determining a radius rb of a test ball; acquiring the rotating speed nbo of the ball when the sliding-rolling ratio s is equal to 0; a lubricating system is started to enable lubricating oil to be sprayed to a ball-disc contact area for lubrication, then servo loading is carried out to enable the ball to make contact with the disc, and the contact stress can be any value in the design range of the contact force of the ball-disc testing machine; when the stress of the load sensor 2 jumps to the stress of the load sensor 1, the rotating speed of the ball driving motor at the moment is obtained to be a critical rotating speed nb '; when the stress of the load sensor 1 jumps to the stress of the load sensor 2, the rotating speed of the ball driving motor is the critical rotating speed nb ''; average value of two critical rotating speeds nb'and nb '' is taken as rotating speed # imgabs0 # imgabs1 # of ball during rolling contact of ball disc, and contact track radius # imgabs2 # of disc

The invention relates to an air suspension high-speed centrifugal compressor applied to the technical field of centrifugal machines, and the air suspension high-speed centrifugal compressor comprises a machine body, a centrifugal rotor, a pneumatic bearing, a magnetic suspension system, an end magnetic disk, a shaft magnet, a brake magnet, a magnetic core, an arc rail groove, a brake module and a steering rib. Vector electromagnetic phase modulation is adopted by the electromagnet, active damping control and gyroscopic effect compensation of the centrifugal rotor are achieved through magnetic field vector synthesis, the centrifugal rotor is accelerated and decelerated through magnetic force, the critical rotation speed acceleration time and deceleration time of the centrifugal rotor are effectively shortened, and the hybrid magnetic locking technology is adopted in the shutdown stage of the centrifugal machine. When the centrifugal rotor is static, the brake module is triggered, magnetic pole reversal of the brake magnet is achieved through a reconstruction mechanism generated by the brake magnet, and the centrifugal rotor is in a stable magnetic attraction brake state through the cooperative magnetic attraction effect of the permanent magnet and the brake magnet.

The application discloses a kind of centrifugal pump shafting critical speed calculation method, including the finite element calculation of radial roller bearing and thrust roller bearing stiffness coefficient curve, the prestressed modal analysis and critical speed calculation of centrifugal pump shafting considering different bearing stiffness coefficient.The setting of constraint condition of this method is in line with actual situation, which can realize the accurate calculation of centrifugal pump shafting critical speed, and help to improve the reliability of safety check of centrifugal pump shafting in design stage, at the same time, the calculation steps are simple, and the engineering application range is wide.

The present invention discloses a parameter optimization design method for a tuned inertia capacitor eddy current damper, which relates to the technical field of damper design and includes the following steps: S01. Determining structural dynamic parameters; S02. Calculating a target effective damping ratio of the structure based on the structural dynamic parameters; S03. Calculating the inertia value, spring stiffness, and linear damping ratio based on the structural dynamic parameters and the target effective damping ratio; S04. Assuming a critical speed; S05. Calculating the peak damping force based on the assumed critical speed, structural dynamic parameters, and linear damping ratio; S06. Determining the conductor material and thickness of the tuned inertia capacitor eddy current damper based on the critical speed, and determining the specifications and quantity of the permanent magnets based on the peak damping force. The present invention establishes, for the first time, a parameter optimization formula for a tuned inertia capacitor eddy current damper, equating the effect of the tuned inertia capacitor eddy current damper to the effective damping ratio of the structure, making it easier for engineering designers to apply.

The invention belongs to the field of rotor design, particularly relates to a high-speed built-in permanent magnet rotor design method, system and equipment based on a stress analysis model, and aims to solve the problem that the structural strength and electromagnetic performance of a high-speed built-in permanent magnet synchronous motor rotor are difficult to collaboratively optimize in the prior art. The method comprises the steps of determining the axial length and the outer diameter of a rotor according to a motor torque demand and an assembly space, and ensuring that a critical rotating speed is higher than a target limit value through dynamic verification; decomposing the rotor into pole shoe, permanent magnet and slotting areas, calculating centrifugal force in different areas, and superposing to obtain a total load; establishing a corresponding stress boundary equation set for a non-magnetic bridge, single / combined magnetic bridge or sheath composite structure; and solving the equation set based on the target rotating speed, and synchronously optimizing the sheath thickness, the magnetic bridge width and the interference magnitude parameter by using the intersection point of the isorotation speed line and the electromagnetic-mechanical characteristic curve. The problem of contradiction between size parameters and performance in traditional design is solved, and calculation efficiency and precision are both considered.

The invention discloses a dynamic balance test control method and system of a flexible rotor, and belongs to the technical field of dynamic balance test control of the flexible rotor, and the method comprises the steps: obtaining a horizontal phase difference between an input end and an output end of a tested rotor and a vertical phase difference between the input end and the output end of the tested rotor, and judging whether a dynamic balance test is carried out or not; obtaining design parameters, a theoretical first critical rotating speed and a theoretical second critical rotating speed of the tested rotor, and obtaining working condition information of the tested rotor; constructing a dynamic balance test control database; constructing a dynamic balance test control model; obtaining a real-time test value; inputting the real-time test value into a dynamic balance parameter adjustment module to obtain a dynamic balance test adjustment parameter; inputting the real-time test result and the working condition information of the tested rotor into a dynamic balance parameter compensation module to obtain a dynamic balance compensation control parameter; the method has the effect of judging whether the dynamic balance test is carried out, and solves the problems of whether the dynamic balance test is carried out and ineffective test behaviors which excessively depend on the dynamic balance test in the prior art.

The invention relates to the technical field of aero-engines, and discloses a damping structure, a working method of the damping structure and an engine rotor system.The damping structure comprises a bush body, an outer ring, a bearing body, an inner ring and an inner ring, a plurality of boss parts are arranged on the side, facing the bearing body in the radial direction, of the bush body, and mounting grooves are formed between every two adjacent boss parts at intervals in the axial direction. The damping ring is mounted in the mounting groove, and the boss part is suitable for limiting the axial displacement of the damping ring; the damping ring is made of viscoelastic materials, and the side, facing the bearing body in the radial direction, of the damping ring elastically abuts against the outer ring of the bearing body, so that an extrusion gap is formed between the outer ring of the bearing body and the inner side circumferential wall of the bush body in the radial direction at intervals. According to the damping structure provided by the invention, an oil supply device and an oil supply path do not need to be arranged, the initial compression amount of the damping ring can be changed by changing the depth of the mounting groove, or by changing the hardness of the damping ring, the effect of adjusting the bearing rigidity so as to adjust the critical rotating speed of the rotor is achieved.

The invention provides a gas-liquid two-phase pump jet propulsion device for an underwater navigation body, and belongs to the technical field of underwater propellers, the gas-liquid two-phase pump jet propulsion device for the underwater navigation body comprises a pump jet assembly, the pump jet assembly is installed in a propeller guide pipe, and the propeller guide pipe is fixedly installed at the rear end of a navigation body shell; the pump jet assembly comprises a paddle shaft, a front stator, a rotor and a rear stator which are sequentially installed in the fluid direction. The gas supply unit comprises a high-pressure gas storage container, the high-pressure gas storage container is communicated with a gas adjusting device through a gas filtering unit, the gas adjusting device is communicated with a gas conveying pipe, the gas conveying pipe is communicated with an annular nozzle, the annular nozzle is connected with an inner cavity of an annular mixing cavity, and the annular mixing cavity is installed in the inner cavity of the annular mixing cavity. The annular mixing cavity is located at the rear end of the pump jet assembly. By fusing the pump spraying momentum transfer principle and the gas-liquid two-phase flow control technology, the thrust can be remarkably improved, and the technical breakthrough of reducing the working noise and improving the cavitation critical speed is synchronously realized.

The invention discloses an airflow excitation numerical analysis method for a thermal barrier coating of a turbine blade at a high temperature, which comprises the following steps of: establishing an external flow field geometric model and a geometric model of the turbine blade containing the thermal barrier coating, and respectively setting computational grids; carrying out modal analysis on the geometric model of the turbine blade by utilizing finite element software to obtain resonance characteristics and critical rotating speed of the turbine blade; fluid analysis software is used for conducting steady-state pneumatic analysis on the external flow field geometric model, a steady-state flow field and a steady-state temperature field of the external flow field geometric model are obtained, the steady-state flow field and the steady-state temperature field serve as initial conditions of an unsteady-state flow field for unsteady-state pneumatic analysis, and a pressure field, changing along with the time period, of the surface of the turbine blade is obtained; interpolating the obtained pressure field to the surface of the thermal barrier coating, introducing the steady-state temperature field into the thermal barrier coating and the turbine blade, and carrying out transient response analysis to obtain stress fields and displacement fields at different moments; and performing time frequency spectrum transformation on the data of the pressure field, the stress field and the displacement field of the dangerous position point by using fast Fourier transform to obtain the dynamic response amplitude and frequency of the thermal barrier coating under airflow excitation.

The invention belongs to the technical field of rotary mechanical system supporting damping, and particularly relates to a throttling ring type elastic supporting structure suitable for an aero-engine rotor system, the throttling ring type elastic supporting structure mainly comprises a bearing, an inner throttling ring, an elastic ring, an outer throttling ring and a bearing seat, and a plurality of staggered bosses are uniformly distributed on the inner surface and the outer surface of the elastic ring and matched with the two throttling rings; and a plurality of oil film cavities which are not directly communicated are formed. After entering the oil cavity through the oil supply channel of the bearing seat, lubricating oil circumferentially flows through the throttling grooves of the inner throttling ring and the outer throttling ring to generate required damping force, so that the vibration amplitude of the rotor when the rotor crosses the critical rotating speed is effectively reduced. Meanwhile, the elastic ring does not need to be provided with a small hole, so that the stress concentration risk is greatly reduced, and the fatigue life and the reliability are remarkably improved. According to the structure, the shape and the size of the throttling groove can be flexibly adjusted to meet different damping requirements, the manufacturing cost is low, and the structure is easy to popularize and apply in high-speed rotating machines such as aero-engines and gas turbines.

The invention provides a rail vehicle derailment simulation method and device, electronic equipment and a storage medium, and the method comprises the steps: obtaining a vehicle-rail system which comprises a rail vehicle model, a steel rail model and a rail plate-sleeper-fastener model; performing model verification on at least one of critical speed, operation stability index and axle box vertical vibration acceleration of the vehicle-rail system; obtaining a derailer model, wherein the derailer model comprises a base, a wedge block and a baffle plate; an acceleration sensor is arranged on a vehicle-rail system, simulation is carried out on the rail vehicle under different working conditions according to simulation configuration, simulation data under different working conditions are collected through a speed sensor, and the simulation data comprise wheel impact corresponding values and vehicle speeds; and calculating the relationship between the wheel impact corresponding value and the vehicle speed to obtain a derailment impact simulation result of the railway vehicle. The method has the beneficial effect that the simulation accuracy of the railway vehicle is improved.

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.

Method for determining a critical speed for rolling movements of a vehicle combination (10), comprising the steps: Determining a yaw rate signal from sensor data, wherein the yaw rate signal characterizes a yaw movement of the vehicle combination; Detection of a rolling movement of the vehicle combination from the yaw rate signal; characterized by Determining the critical speed from a damping curve of the yaw rate signal, wherein the critical speed is a trailer speed of the trailer at which amplitudes of the yaw rate signal remain substantially constant, and further comprising: Storing a predefined value for the critical speed; Recursively modify the value for the critical speed by: Determine that the critical speed is greater than the current trailer speed when no rolling motion occurs, and / or Determine that the critical speed is greater than the current trailer speed when amplitudes of the yaw rate signal decrease during the roll motion, and / or Determine that the critical speed is less than the current trailer speed when amplitudes of the yaw rate signal increase during the roll motion; Increase or decrease the value for the critical speed if the critical speed is greater or less than the value for the critical speed, wherein, in addition, a decay or rise gradient of the oscillation is determined and, in response to this decay or rise gradient exceeding a predetermined threshold value, a step size with which the value of the critical speed is changed is increased.

The invention relates to the technical field of aero-engines, in particular to a rotor supporting structure which comprises a supporting cylinder, a worm gear, a worm and a pressing block. A plurality of strip-shaped holes are formed in the side face of the supporting cylinder, and the strip-shaped holes are distributed in the circumferential side direction of the supporting cylinder. The worm gear rotationally sleeves the supporting cylinder; the worm is meshed with the worm gear; the pressing blocks are fixedly arranged on the inner wall of the worm gear, the pressing blocks correspond to the strip-shaped holes one to one, and the pressing blocks are partially located in the corresponding strip-shaped holes; when the worm gear rotates in the circumferential direction, the pressing blocks can be driven to extrude the side walls of the corresponding strip-shaped holes so as to change the rigidity of the rotor supporting structure. According to the variable-stiffness rotor supporting structure capable of performing active control, when a modern aero-engine operates under variable working conditions, the supporting stiffness can be actively controlled under different working conditions, the effects of being away from the critical rotating speed and reducing the resonance peak value are achieved, rotor vibration response suppression is achieved, and therefore the effect of reducing vibration of the aero-engine is achieved.

The paddle comprises a round hub connected with a mandrel, a plurality of blades are fixedly connected in the circumferential direction of the round hub, the round hub comprises a round pipe, clamping pieces are fixedly connected to the two ends of the round pipe, positioning grooves are formed in the circumferential directions of the clamping pieces, the two ends of the blades are fixedly connected to the positioning grooves, and the outer diameter of the round pipe is smaller than that of the clamping pieces. According to the paddle of the film evaporator, the structure of the circular hub is changed, the overall weight of the paddle is reduced, and the critical rotating speed of the paddle is increased.

A turbomachine engine including an engine core including a high-pressure compressor, which has an exit stage having an exit stage diameter (DCORE), a high-pressure turbine, and a combustion chamber in flow communication with the high-pressure compressor and the high-pressure turbine, a power turbine in flow communication with the high-pressure turbine, and a low-pressure shaft coupled to the power turbine and characterized by a midshaft rating (MSR) between two hundred (ft / sec)1 / 2 and three hundred (ft / sec)1 / 2. The low-pressure shaft has a redline speed between fifty and two hundred fifty feet per second (ft / sec). The turbomachine engine is configured to operate up to the redline speed without passing through a critical speed associated with a first-order bending mode of the low-pressure shaft. The low-pressure shaft has a length (LMSR) defined by an engine core length (LCORE) given by:LCORE=[m(20+m)*n(10+n)](1100)*DCORE+CIS.

The application discloses a multi-bearing segmented flywheel energy storage device, which comprises an upper bearing, a lower bearing, a middle bearing, a shell, a rotating shaft, a first flywheel and a second flywheel. The two flywheels are arranged on the rotating shaft, the shell is arranged outside the flywheels and the rotating shaft, the upper bearing and the lower bearing are arranged at two ends of the rotating shaft, the middle bearing is arranged on the rotating shaft between the two flywheels, and the middle bearing is arranged between the shell and the rotating shaft. The first flywheel is integrally formed with the rotating shaft, and the second flywheel is detachably connected with the rotating shaft. The application is used to solve the problem of excessive radial vibration caused by the first critical speed being too low due to the large axial span of the flywheel. The flywheel body with large thickness is divided into two parts, which is beneficial to the uniformity of the heat treatment of the flywheel body. The radial strength of the rotating shaft of the flywheel body is improved by additionally arranging a bearing between the two flywheel bodies. In order to facilitate the installation of the bearing at the middle position of the flywheel, the segmented flywheel rotating shaft and the matched shell are designed.

A flexible drive shaft (10) for transmitting torque from a motor (4) to a high-speed rotor (2), particularly for a laboratory centrifuge (1), wherein the material of the drive shaft (10) has a defined yield strength and a defined modulus of elasticity. To create a new drive unit, for example for a laboratory centrifuge, that retains the necessary flexibility at critical speeds but exhibits higher strength with respect to bending stresses, it is proposed that a material be used for the drive shaft (10) in which the yield strength of the material is expressed in N / mm². 2 divided by the material's modulus of elasticity in N / mm 2 takes on a value > 0.0045.

The present invention discloses a load compressor configuration, comprising: a rotor assembly, and a first bearing casing and an air intake casing relatively spaced apart and installed on the outer circles at both ends of the rotor assembly. The power input end of the rotor assembly is supported on the first bearing casing through a front bearing, and the power output end of the rotor assembly is supported on the air intake casing through a rear bearing to form an independent rotor support structure. The power input end of the rotor assembly can also be detachably connected to the upstream power input system, and the power output end of the rotor assembly can also be detachably connected to the downstream power output system to ensure the input and output of the load compressor power. The present invention can form an independent rotor system, ensure an independent unit design, and then can be quickly adapted to auxiliary power units of different models and powers, with a wide range of adaptability; the rotor assembly has a short fulcrum span and strong rigidity, ensuring that the rotor system has sufficient critical speed margin.

The invention discloses a sensorless control method for a staggered magnetic pole series-parallel magnetic circuit doubly salient bearingless motor, and the method mainly comprises the steps: introducing a catfish effect, and based on a conventional particle swarm algorithm, providing an improved catfish effect quantum particle swarm algorithm. Therefore, the problem of simultaneous detection of two rotor space positions of the tangential position and the radial displacement signal of the rotor of the staggered magnetic pole series-parallel magnetic circuit doubly salient bearingless motor is solved. The method overcomes the limitation of a mechanical sensor on the increase of the critical rotating speed, reduces the manufacturing cost of the system, has better capability of quickly locking a signal target and quickly converging a function compared with the traditional particle swarm algorithm, and improves the signal detection efficiency.

The present invention relates to a robust prediction method for centrifugal pump rotor dynamics with uncertain bearing parameters, and belongs to the field of multi-stage centrifugal pumps. Aiming at the problem of uncertain dynamic characteristics of a multi-stage centrifugal pump rotor system caused by manufacturing errors of sliding bearing structural parameters, the present invention proposes a robust prediction method for the critical speed of the rotor system based on rotor system dynamics simulation and improved particle swarm optimization algorithm. The method establishes a rotor system dynamics model through dynamic characteristic coefficients associated with the structural parameters of the sliding bearing, realizes automatic calculation of the critical speed of the multi-stage centrifugal pump rotor system when the bearing structural parameters change by joint simulation of MATLAB and ANSYS, establishes an optimization model with structural parameters such as the shaft diameter length, clearance ratio, aspect ratio and oil film viscosity coefficient of the sliding bearing as variables, and the critical speed of the rotor system as the target, and calculates the critical speed extreme value of the rotor system dynamics model by combining finite element simulation and improved particle swarm optimization algorithm. In addition, a large number of bearing structural parameters are sampled by using the Monte Carlo algorithm to verify the accuracy and effectiveness of the solution results of the improved particle swarm optimization algorithm. The present invention can accurately and efficiently predict the robust critical speed of the rotor system, which is helpful for the reliable design and operation of the rotor system, and provides a theoretical basis for the design of the rotor system of a multi-stage centrifugal pump.

A turbomachine engine includes an engine core including a high-pressure compressor, a high-pressure turbine, and a combustion chamber. The engine core has a length (LCORE), and the high-pressure compressor has an exit stage diameter (DCORE). A power turbine is in flow communication with the high-pressure turbine. A low-pressure shaft is coupled to the power turbine and characterized by a midshaft rating from one hundred fifty (ft / sec)1 / 2 to three hundred thirty (ft / sec)1 / 2. The low-pressure shaft has a redline speed between fifty and two hundred fifty feet per second. The turbomachine engine is configured to operate up to the redline speed without passing through a critical speed associated with a first-order bending mode of the low-pressure shaft. A high-pressure shaft is coupled to the high-pressure compressor and the high-pressure turbine and is characterized by a high-speed shaft rating from 1.5 to 6.2, and a ratio of LCORE / DCORE is from 2.1 to 4.3.

A turbomachine engine including an engine core including a high-pressure compressor, which has an exit stage having an exit stage diameter (DCORE), a high-pressure turbine, and a combustion chamber in flow communication with the high-pressure compressor and the high-pressure turbine, a power turbine in flow communication with the high-pressure turbine, and a low-pressure shaft coupled to the power turbine and characterized by a midshaft rating (MSR) between two hundred (ft / sec)1 / 2 and three hundred (ft / sec)1 / 2. The low-pressure shaft has a redline speed between fifty and two hundred fifty feet per second (ft / sec). The turbomachine engine is configured to operate up to the redline speed without passing through a critical speed associated with a first-order bending mode of the low-pressure shaft. The low-pressure shaft has a length (LMSR) defined by an engine core length (LCORE) given by:LCORE=[m  (20+m)*n  (10+n)](1100)*DCORE+CIS.

The invention belongs to the field of engine design, and particularly relates to an aero-engine whole machine dynamic structure design parameter optimization method, which utilizes an APDL language of ANSYS software to carry out parametric modeling on an aero-engine whole machine (including a rotor, a support and a stator casing), and applies additional centrifugal force and additional gyroscopic moment generated by maneuvering flight. The stress level of the bearing case, the strain energy distribution of a rotor system and the rotor and stator gap change are obtained through bearing case stress analysis, critical speed analysis and unbalanced response analysis. Based on the analysis results, multi-objective optimization is carried out on complete machine dynamic design parameters, so that the stress level of a force bearing casing is lowest, rotor strain energy distribution meets rotor dynamic design requirements, rotor and stator gap changes are minimum, the rub-impact risk is reduced, optimization of the structural design parameters is completed through software, the design efficiency is improved, and the design cost is reduced. The design period is shortened.