Dynamic characteristics analysis of blade-casing rubbing faults with abradable coatings

2020 ◽  
pp. 095440622094155
Author(s):  
Junhong Zhang ◽  
Xin Lu ◽  
Jiewei Lin ◽  
Liang Ma ◽  
Huwei Dai
Keyword(s):  
Rotor System ◽  
Rotating Speed ◽  
Fundamental Frequencies ◽  
Abradable Coating ◽  
Characteristics Analysis ◽  
Blade Tip ◽  
System Vibration ◽  
Initial Clearance ◽  
Abradable Coatings ◽  
Dynamic Characteristics Analysis

In this paper, a dynamic model of a “0-2-1” rotor system with rubbing fault between blade and abradable coated casings is developed. The sub-model of rubbing force considers scraping work energy of coating, casing stiffness, and initial clearance between blade tip and casing. A rotor rig is established and samples of abradable coatings are introduced into the rubbing experiment. Vibration characteristics of the rotor system under blade-casing rubbing fault are analyzed. Effects of rotating speed and initial clearance on the rub force and the system vibration are studied. Results show that the vibration of rotor focuses on the fundamental and multiple fundamental frequencies due to the blade-casing rubbing with the abradable coating. The multiple fundamental frequencies, the 2 × and 3 × in particular, are greatly affected by the rotating speed. The fractional harmonic frequencies are strongly influenced by the initial clearance between the blade tip and casing. Besides, the rotating speed and the initial clearance between the blade tip and abradable coating on the casing also affect the amplitude and distribution of the rub force.

Mechanical Design of Wound Composite Impeller Using FEM

2010 ◽  
Author(s):  
Jifeng Wang ◽  
Mohit Patil ◽  
Jorge Olortegui-Yume ◽  
Norbert Mu¨ller
Keyword(s):  
High Performance ◽  
Mechanical Design ◽  
Low Cost ◽  
Design Parameters ◽  
Rotating Speed ◽  
Characteristics Analysis ◽  
High Performance Composite ◽  
The Relationship ◽  
Dynamic Characteristics Analysis ◽  
Wound Composite

A low-cost, light-weight, high-performance, composite turbomachinery impeller with uniquely designed blade patterns is analyzed. Such impellers can economically enable refrigeration plants to use water as a refrigerant (R718). A stress and vibration analyses procedure is developed to assess the maximum stresses and natural frequencies of these wound composite axial impellers under operating loading conditions using Finite Element Method. A commercially available software ANSYS is used for the FE calculations. Analysis is done for two different blade geometries and then suggestions are made for optimum design parameters. The relationship between impeller natural frequency and rotating speed is also determined based on dynamic characteristics analysis.

scholarly journals Simulation and Experimental Study on Rotor System Dynamic Analysis with the Blade-Coating Rubbing Faults

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Xin Lu ◽  
Jie Tang ◽  
Liwen Wang
Keyword(s):  
Dynamic Characteristics ◽  
Influence Factors ◽  
Rotor System ◽  
System Dynamic ◽  
Force Model ◽  
Power Performance ◽  
Abradable Coating ◽  
Increased Risk ◽  
Blade Tip ◽  
Blade Coating

In the modern turbo-machinery, reducing the clearance between the blade tip and casing inner face is an effective method to improve the power performance, but the clearance reduction leads to increased risk of blade-casing rubbing. In this paper, a blade-coating rubbing force model which considered the abradable coating scraping is developed to simulate the rotor system dynamic characteristics at blade-casing rubbing faults with abradable coating. An experimental tester is established to simulate the rotor system blade-casing rubbing faults; the AlSi-ployphenyl ester abradable coating is prepared and introduced into the blade-casing experiment to verify the model. After the vibration and force analysis in simulation and experiment, the dynamic characteristics and the influence factors of blade-casing rubbing rotor system are studied.

scholarly journals Vibration characteristics of triple-gear-rotor system in compressed air energy storage under variable torque load

2021 ◽  
Vol 104 (1) ◽  
pp. 003685042098705
Author(s):  
Xinran Wang ◽  
Yangli Zhu ◽  
Wen Li ◽  
Dongxu Hu ◽  
Xuehui Zhang ◽  
...  
Keyword(s):  
Large Scale ◽  
Three Dimensional ◽  
Element Model ◽  
Rotor System ◽  
Dynamic Responses ◽  
System Response ◽  
Rotating Speed ◽  
Torque Load ◽  
Set Up ◽  
Two Stages

This paper focuses on the effects of the off-design operation of CAES on the dynamic characteristics of the triple-gear-rotor system. A finite element model of the system is set up with unbalanced excitations, torque load excitations, and backlash which lead to variations of tooth contact status. An experiment is carried out to verify the accuracy of the mathematical model. The results show that when the system is subjected to large-scale torque load lifting at a high rotating speed, it has two stages of relatively strong periodicity when the torque load is light, and of chaotic when the torque load is heavy, with the transition between the two states being relatively quick and violent. The analysis of the three-dimensional acceleration spectrum and the meshing force shows that the variation in the meshing state and the fluctuation of the meshing force is the basic reasons for the variation in the system response with the torque load. In addition, the three rotors in the triple-gear-rotor system studied show a strong similarity in the meshing states and meshing force fluctuations, which result in the similarity in the dynamic responses of the three rotors.

Feasibility investigation of a compressor rotor supported by gas foil bearings with inhomogeneous bump foils

2021 ◽  
pp. 135065012110046
Author(s):  
Hao Li ◽  
Haipeng Geng ◽  
Bo Wang ◽  
Wei Zheng
Keyword(s):  
Critical Speed ◽  
Rotor System ◽  
Experimental Result ◽  
Test Results ◽  
Rotating Speed ◽  
Foil Bearings ◽  
Dynamic Coefficients ◽  
High Order Harmonic ◽  
Compressor Rotor ◽  
Operating Points

In this paper, a rotordynamic experiment on a compressor rotor system is presented and the feasibility of gas foil bearings with inhomogeneous bump foils is verified. A push–pull device is designed to obtain the stiffness curve and the nominal clearance of foil bearings. Operating points and dynamic coefficients of the rotor system at each rotating speed are predicted. In rotordynamic analysis, an alternative model of the impeller is proposed and the critical speed is predicted by employing the finite element method, in which the dynamic coefficients of inhomogeneous foil bearings are taken into account. Compared with the experimental result, the accuracy of the prediction for the critical speed is verified to be about 14% error. Two sets of foil bearings with 22 and 41 μm nominal clearance are manufactured and tested. Test results indicate that the vibration amplitude can be greatly reduced by diminishing the bearing clearance. When foil bearings with 22 μm clearance are used, the high-order harmonic frequencies of rotor vibration are significantly inhibited, and the amplitude of the rotating frequency is obviously restricted. Thus, the foil bearing with inhomogeneous bump foils tested in this paper can meet the speed requirement of the compressor when the nominal clearance is set at 22 μm.

Dynamic Characteristics Analysis of Cable-Rib Tension Deployable Antenna

2016 ◽  
Author(s):  
Liu Ruiwei ◽  
Hongwei Guo ◽  
Zhang Qinghua ◽  
Rongqiang Liu ◽  
Tang Dewei
Keyword(s):  
Dynamic Characteristics ◽  
Structural Parameters ◽  
Element Model ◽  
Structure Design ◽  
Antenna Structure ◽  
Characteristics Analysis ◽  
New Type ◽  
Dynamic Characteristics Analysis ◽  
The Finite Element Model ◽  
Weight Dynamic

Balancing stiffness and weight is of substantial importance for antenna structure design. Conventional fold-rib antennas need sufficient weight to meet stiffness requirements. To address this issue, this paper proposes a new type of cable-rib tension deployable antenna that consists of six radial rib deployment mechanisms, numerous tensioned cables, and a mesh reflective surface. The primary innovation of this study is the application of numerous tensioned cables instead of metal materials to enhance the stiffness of the entire antenna while ensuring relatively less weight. Dynamic characteristics were analyzed to optimize the weight and stiffness of the antenna with the finite element model by subspace method. The first six orders of natural frequencies and corresponding vibration modes of the antenna structure are obtained. In addition, the effects of structural parameters on natural frequency are studied, and a method to improve the rigidity of the deployable antenna structure is proposed.

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