Transient tribo-dynamic model for journal bearings during start-up considering 3D thermal characteristic

2020 ◽  
Vol 144 ◽  
pp. 106123 ◽  
Author(s):  
Guo Xiang ◽  
Yanfeng Han ◽  
Tao He ◽  
Jiaxu Wang ◽  
Ke Xiao ◽  
...  
Keyword(s):  
Dynamic Model ◽  
Thermal Characteristic ◽  
Journal Bearings ◽  
Start Up

scholarly journals Electromechanical Dynamic Behaviour and Start-Up Evaluation of Tumbling Ball Mills

2018 ◽  
Vol 2018 ◽  
pp. 1-13
Author(s):  
Weidong Lv ◽  
Guoqiang Wang ◽  
He Tian
Keyword(s):  
Dynamic Model ◽  
Ball Mill ◽  
Electromechanical Coupling ◽  
Coupling Model ◽  
Angular Speed ◽  
Experimental Results ◽  
Ball Mills ◽  
Start Up ◽  
Dynamic Simulator ◽  
Simulation Results

This paper presents a dynamic simulator of the electromechanical coupling start-up of a ball mill. The electromechanical coupling model based on the dynamic model of the ball mill, the characteristic equation of the clutch, and the dynamic model of the induction motor is established. Comparison between the simulation results of angular speed, load torque and current obtained from the model, and the experimental results is conducted to validate the correctness of these simulation results. Results show that the simulation results of the electromechanical model are highly consistent with the experimental results. Two indexes are proposed for evaluation. Finally, a 4500 kW ball mill is used to analyse the start-up process with different operation parameters of the air clutch. The effect of the engagement time and the pressure of the air clutch on the torque, current, and shock extent is analysed. Moreover, the optimum inflation time is determined.

AXIAL-FLOW BLOOD PUMP ACCELERATION CONTROL METHOD BASED ON A START-UP PROCESS DYNAMIC MODEL

2017 ◽  
Vol 41 (5) ◽  
pp. 691-705
Author(s):  
Xu Yan ◽  
Pang Youxia ◽  
Cheng Lizhi ◽  
Liang Liang
Keyword(s):  
Dynamic Model ◽  
Control Method ◽  
Axial Flow ◽  
Test System ◽  
Blood Pump ◽  
Theoretical Simulation ◽  
Process Dynamic ◽  
Axial Flow Blood Pump ◽  
Start Up ◽  
Set Up

The principle of a large gap magnetic drive system was used to achieve control of an axial-flow blood pump. A dynamic model of the start-up process of the axial-flow blood pump was established. It was analyzed and simulated. An acceleration control method for the blood pump was proposed based on the start-up process dynamic model. A corresponding parameter measurement test system was set up, and experimental data were compared with the results of the theoretical simulation. Results indicated that the experimental values obtained for the blood pump outlet pressure and flow rate changed similarly with the values obtained using theoretical simulation. These changes occurred simultaneously with the change in speed of the blood pump over time, and the driving control target value was reached within 4 seconds.

Model-Based Investigation of Friction During Start-Up of Hydrodynamic Journal Bearings

1995 ◽  
Vol 117 (4) ◽  
pp. 667-673 ◽  
Author(s):  
A. Harnoy
Keyword(s):  
Friction Model ◽  
Journal Bearings ◽  
Time Variable ◽  
Stribeck Curve ◽  
Dynamic Friction ◽  
Stick Slip ◽  
Friction Characteristics ◽  
Start Up ◽  
Variable Friction ◽  
Steady Velocity

An analysis is developed for the time-variable friction during the start-up of a rotor system. The analysis is based on a dynamic friction model that has been developed from the theory of unsteady lubrication and can describe the observed friction characteristics. The model reduces to the Stribeck curve of friction versus steady velocity, and shows hysteresis curves in oscillating velocity. The “Dahl effect” of a presliding displacement before the breakaway is also included. The results indicate that the friction characteristics and energy friction losses, during the start-up, depend on a set of dimensionless parameters that represent the bearing as well as the dynamic system. The study shows that appropriate design and operation can prevent stick-slip friction and minimize wear during start-up.

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