scholarly journals A Vibration Suppression Method for the Multistage Rotor of an Aero-Engine Based on Assembly Optimization

Machines ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 189
Author(s):  
Yue Chen ◽  
Jiwen Cui ◽  
Xun Sun
Keyword(s):  
Vibration Suppression ◽  
Optimization Methods ◽  
Optimization Method ◽  
Rotor System ◽  
Vibration Velocity ◽  
Transfer Model ◽  
Dynamics Model ◽  
Aero Engine ◽  
Vibration Responses ◽  
Optimal Assembly

The assembly quality of the multistage rotor is an essential factor affecting its vibration level. The existing optimization methods for the assembly angles of the rotors at each stage can ensure the concentricity and unbalance meet the requirements, but it cannot directly ensure its vibration responses meet the indexes. Therefore, in this study, we first derived the excitation formulas of the geometric and mass eccentricities on the multistage rotor and introduced it into the dynamics model of the multistage rotor system. Then, the coordinate transfer model of the geometric and mass eccentricities errors, including assembly angles of the rotors at all stages, was established. Moreover, the mathematical relationship between the assembly angles of the rotors at all stages and the nodal vibration responses was established by combining the error transfer model with the dynamics model of the multistage rotor system. Furthermore, an optimization function was developed, which takes the assembly angles as the optimization variables and the maximum vibration velocity at the bearings as the optimization objective. Finally, a simplified four-stage high-pressure rotor system was assembled according to the optimal assembly angles calculated in the simulations. The experimental results showed that the maximum vibration velocity at the bearings under the optimal assembly was reduced by 69.6% and 45.5% compared with that under the worst assembly and default assembly. The assembly optimization method proposed in this study has a significant effect on the vibration suppression of the multistage rotor of an aero-engine.

scholarly journals Analysis on Influences of Squeeze Film Damper on Vibrations of Rotor System in Aeroengine

2022 ◽  
Vol 12 (2) ◽  
pp. 615
Author(s):  
Haobo Wang ◽  
Yulai Zhao ◽  
Zhong Luo ◽  
Qingkai Han
Keyword(s):  
High Speed ◽  
Vibration Suppression ◽  
Rotor System ◽  
Operating Conditions ◽  
Squeeze Film ◽  
Lumped Mass ◽  
Squeeze Film Damper ◽  
Rotor Systems ◽  
Vibration Responses ◽  
Stiffness And Damping

Squeeze film damper (SFD) is widely used in the vibration suppression of aeroengine rotor systems, but will cause complex motions of the rotor system under specific operating conditions. In this paper, a lumped-mass dynamic model of the high-pressure rotor system in an aeroengine is established, and the nonlinear stiffness and damping formula of SFD are introduced into the above model. The vibration responses of the rotor system under different rotating speeds and with different unbalances are investigated numerically, and the influence of SFD on the rotor system vibration and the change of suppression ability are compared and analyzed. The results show that in the case of high speed, together with a small unbalance, the rotor system will perform a complex vibration or a bistable vibration due to SFD. If the unbalance is properly increased under the same case of high speed, the vibration of the rotor becomes single-harmonic and the bistable vibration disappears. The research results can provide a helpful reference for analyzing complex vibration mechanisms of the rotor system with SFD and achieving an effective vibration suppression through unbalance regulation.

Estimation of Rotor-Bearing Parameters by a Global Optimization Method

2006 ◽  
Author(s):  
E. A. Khorshid ◽  
A. H. Falah
Keyword(s):  
Journal Bearing ◽  
Optimization Methods ◽  
Optimization Method ◽  
Air Gap ◽  
Outer Diameter ◽  
Rotor Bearing ◽  
Vibration Responses ◽  
Optimized Model ◽  
Stiffness And Damping ◽  
Good Agreement

Modeling, experiments and system identification of the linear dynamics of a flexible multi-bearing rotor with two concentrated disks are presented in this paper. Both rotor unbalanced vibration responses through critical speeds were experimentally obtained through accurate control of journal bearing static load. Vibration simulations of this laboratory rotor-bearing system were performed as a linear system. The simulation and the experimental results have large differences for both rotors. These differences occur because of (1)The errors in estimating the journal bearing damping and stiffness coefficients, and, (2)The neglect of the effect of the small radial air gap (20 Mils) at the two disks' outer diameter which provides some additional bearing-like radial stiffness and damping effects. An estimate of these coefficients for both the journal bearing and the rotor-radial air gap is obtained using optimization methods. Good agreement was found between the experimental and the optimized model.

Multi-Objective Optimization of a Two-Disk Rotor System

2014 ◽  
Vol 705 ◽  
pp. 79-82
Author(s):  
Jing Jing Huang ◽  
Long Xi Zheng ◽  
Mei Qing
Keyword(s):  
Design Optimization ◽  
High Speed ◽  
Maximum Amplitude ◽  
Optimization Method ◽  
Rotor System ◽  
Practical Significance ◽  
Flexible Rotor ◽  
Multi Objective ◽  
Aero Engine ◽  
Minimum Amplitude

A two-disk rotor system under the aero-engine support structure of typical 1-0-1 was established and the dynamical characteristics were analyzed. The two-disk rotor model was integrated to the Isight. The multi-objective design optimization of the transient process was then carried out with Evolutionary Optimization Algorithm. The optimum positions of the two-disk rotor system were obtained at the specified constraints. In order to verify the validity of the design optimization, the transient test was carried out on a high-speed flexible rotor mockup. The maximum amplitude of disk 1 cross the first critical rotation speed fell 50% and the maximum amplitude of disk 2 decreased by 20%. Experimental results indicated that the optimization method could obtain the position of the flexible rotor with the minimum amplitude and improve the design efficiency and quality, which had practical significance in the design of aero-engine rotor system.

scholarly journals An Assembly Method for the Multistage Rotor of An Aero-Engine Based on the Dual Objective Synchronous Optimization for the Coaxality and Unbalance

Aerospace ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 94
Author(s):  
Yue Chen ◽  
Jiwen Cui ◽  
Xun Sun
Keyword(s):  
Genetic Algorithm ◽  
High Speed ◽  
Objective Evaluation ◽  
Optimization Method ◽  
Transmission Model ◽  
Good Convergence ◽  
Monte Carlo Simulation Technique ◽  
Assembly Method ◽  
Aero Engine ◽  
Optimal Assembly

The assembly quality of an aero-engine directly determines its stability in high-speed operation. The coaxiality and unbalance out of tolerance caused by improper assembly may give rise to complicated vibration faults. To meet the requirements of the dual objective and reduce the test cost, it is necessary to predict the optimal assembly angles of the rotors at each stage during pre-assembly. In this study, we proposed an assembly optimization method for a multistage rotor of an aero-engine. Firstly, we developed a coordinate transmission model to calculate the coordinates of any point in the rotors at each stage during the assembly processes of a multistage rotor. Moreover, we proposed two different pieces of assembly optimization data for the coaxiality and unbalance, and established a dual objective evaluation function of that. Furthermore, we used the genetic algorithm to solve the optimal assembly angles of the rotors at each stage. Finally, the Monte Carlo simulation technique was used to investigate the effects of the geometric measured errors of each rotor on the proposed genetic algorithm. The simulation results show that the process of the dual objective optimization had good convergence, and the obtained optimal assembly angles of each rotor were not affected by the geometric measured errors. In addition, the dual objective optimization can ensure that both the coaxiality and unbalance can approach their respective optimal values to the most extent, and the experimental results also verified this conclusion. Therefore, the assembly optimization method proposed in this study can be used to guide the assembly processes of the multistage rotor of an aero-engine to achieve synchronous optimization for the coaxality and unbalance.

scholarly journals A Co-Optimization Method of Actuators/Sensors Placement and LQG Controller for Vibration Suppression

IEEE Access ◽  
2021 ◽  
Vol 9 ◽  
pp. 29482-29489
Author(s):  
Peijin Zhang ◽  
Chengyang Ding ◽  
Yunlang Xu ◽  
Runze Ding ◽  
Xiaofeng Yang ◽  
...  
Keyword(s):  
Vibration Suppression ◽  
Optimization Method

scholarly journals Target Localization Based on Bistatic T/R Pair Selection in GNSS-Based Multistatic Radar System

2021 ◽  
Vol 13 (4) ◽  
pp. 707
Author(s):  
Yu’e Shao ◽  
Hui Ma ◽  
Shenghua Zhou ◽  
Xue Wang ◽  
Michail Antoniou ◽  
...  
Keyword(s):  
Optimization Methods ◽  
Optimization Method ◽  
Satellite System ◽  
Radar System ◽  
Target Localization ◽  
Computational Load ◽  
Matrix Fusion ◽  
Global Navigation Satellite ◽  
Multistatic Radar ◽  
Combined Algorithm

To cope with the increasingly complex electromagnetic environment, multistatic radar systems, especially the passive multistatic radar, are becoming a trend of future radar development due to their advantages in anti-electronic jam, anti-destruction properties, and no electromagnetic pollution. However, one problem with this multi-source network is that it brings a huge amount of information and leads to considerable computational load. Aiming at the problem, this paper introduces the idea of selecting external illuminators in the multistatic passive radar system. Its essence is to optimize the configuration of multistatic T/R pairs. Based on this, this paper respectively proposes two multi-source optimization algorithms from the perspective of resolution unit and resolution capability, the Covariance Matrix Fusion Method and Convex Hull Optimization Method, and then uses a Global Navigation Satellite System (GNSS) as an external illuminator to verify the algorithms. The experimental results show that the two optimization methods significantly improve the accuracy of multistatic positioning, and obtain a more reasonable use of system resources. To evaluate the algorithm performance under large number of transmitting/receiving stations, further simulation was conducted, in which a combination of the two algorithms were applied and the combined algorithm has shown its effectiveness in minimize the computational load and retain the target localization precision at the same time.

scholarly journals Exploration of Semantic Geo-Object Recognition Based on the Scale Parameter Optimization Method for Remote Sensing Images

2021 ◽  
Vol 10 (6) ◽  
pp. 420
Author(s):  
Jun Wang ◽  
Lili Jiang ◽  
Qingwen Qi ◽  
Yongji Wang
Keyword(s):  
Parameter Optimization ◽  
Scale Parameter ◽  
Human Perception ◽  
Optimization Methods ◽  
Optimization Method ◽  
Initiation Point ◽  
Scale Parameters ◽  
Object Based ◽  
Geographic Object ◽  
Multiresolution Segmentation

Image segmentation is of significance because it can provide objects that are the minimum analysis units for geographic object-based image analysis (GEOBIA). Most segmentation methods usually set parameters to identify geo-objects, and different parameter settings lead to different segmentation results; thus, parameter optimization is critical to obtain satisfactory segmentation results. Currently, many parameter optimization methods have been developed and successfully applied to the identification of single geo-objects. However, few studies have focused on the recognition of the union of different types of geo-objects (semantic geo-objects), such as a park. The recognition of semantic geo-objects is likely more crucial than that of single geo-objects because the former type of recognition is more correlated with the human perception. This paper proposes an approach to recognize semantic geo-objects. The key concept is that a single geo-object is the smallest component unit of a semantic geo-object, and semantic geo-objects are recognized by iteratively merging single geo-objects. Thus, the optimal scale of the semantic geo-objects is determined by iteratively recognizing the optimal scales of single geo-objects and using them as the initiation point of the reset scale parameter optimization interval. In this paper, we adopt the multiresolution segmentation (MRS) method to segment Gaofen-1 images and tested three scale parameter optimization methods to validate the proposed approach. The results show that the proposed approach can determine the scale parameters, which can produce semantic geo-objects.

Comparison between Optimization Method and Experience-Based Method in Soil Conservation

2013 ◽  
Vol 726-731 ◽  
pp. 3811-3817
Author(s):  
Yuan Feng ◽  
Ji Xian Wang
Keyword(s):  
Slope Stability ◽  
Soil Conservation ◽  
Computer Aided Design ◽  
Optimization Methods ◽  
Optimization Method ◽  
Interaction Function ◽  
The Standard Model ◽  
Computer Aided ◽  
Slice Method ◽  
Aided Design

The analysis of the slope stability is important in soil conservation. To analyze the slope stability, optimization methods were coded and compared with the traditional experience-based methods. Furthermore, the results were visualized in the program, so that the user can easily check the results and can designate an area, in which the program seeks the center and radius of the most hazardous slide arc. Moreover, the graphic interaction function was implemented in the program. In addition, the Standard Model One, recommended by ACAD (The Association for Computer Aided Design), was calculated by the program, of which the results (safety factor Ks=0.95~0.96) were smaller than the official recommend value (Ks=1). It is because that the traditional slice method, which neglects the normal stress and shear stress between the slices, was applied for calculation of Ks.

scholarly journals Cable Suspension and Balance System with Low Support Interference and Vibration for Effective Wind Tunnel Tests

2021 ◽  
Author(s):  
Keum-Yong Park ◽  
Yeol-Hun Sung ◽  
Jae-Hung Han
Keyword(s):  
Wind Tunnel ◽  
Vibration Suppression ◽  
Aerodynamic Load ◽  
Test Model ◽  
Wind Tunnel Tests ◽  
Balance System ◽  
Motion Responses ◽  
Vibration Responses ◽  
Aerodynamic Interference ◽  
Support Interference

AbstractA cable-driven model support concept is suggested and implemented in this paper. In this case, it is a cable suspension and balance system (CSBS), which has the advantages of low support interference and reduced vibration responses for effective wind tunnel tests. This system is designed for both model motion control and aerodynamic load measurements. In the CSBS, the required position or the attitude of the test model is realized by eight motors, which adjust the length, velocity, and acceleration of the corresponding cables. Aerodynamic load measurements are accomplished by a cable balance consisting of eight load cells connected to the assigned cables. The motion responses and load measurement outputs were in good agreement with the reference data. The effectiveness of the CSBS against aerodynamic interference and vibration is experimentally demonstrated through comparative tests with a rear sting and a crescent sting support (CSS). The advantages of the CSBS are examined through several wind tunnel tests of a NACA0015 airfoil model. The cable support of the CSBS clearly showed less aerodynamic interference than the rear sting with a CSS, judging from the drag coefficient profile. Additionally, the CSBS showed excellent vibration suppression characteristics at all angles of attack.

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