scholarly journals Dynamic characteristics of the gear-rotor system in compressed air energy storage considering friction effects

2021 ◽  
Vol 12 (1) ◽  
pp. 677-688
Author(s):  
Xinran Wang ◽  
Wen Li ◽  
Dongxu Hu ◽  
Xingjian Dai ◽  
Haisheng Chen
Keyword(s):  
Energy Storage ◽  
Friction Coefficient ◽  
Dynamic Characteristics ◽  
Surface Friction ◽  
Rotor System ◽  
Compressed Air ◽  
Contact Temperature ◽  
Tooth Surface ◽  
Compressed Air Energy Storage ◽  
Rotating Speed

Abstract. The tooth surface friction effects and the resulting tooth surface contact temperature are important factors for the dynamic characteristics of a gear-rotor system in compressed air energy storage (CAES). Therefore, a 3∘ of freedom finite-element model of the system is set up in which the lubrication state of the gear pair, tooth surface friction, contact temperature of the tooth surface, backlash and unbalanced excitation are considered. The friction coefficient is calculated according to the variation of the lubrication state, and the tooth surface contact temperature is derived based on the friction coefficient. The tooth profile deformation caused by the change in the contact temperature is calculated, and the resulting effects on backlash and comprehensive meshing stiffness are considered. The influence of rotating speed, torque load and viscosity of lubricating oil on the system response is studied, and the variation of the friction coefficient, flash temperature of the tooth surface, pressure of the tooth surface and so on are discussed in detail. The results indicate that when the friction coefficient is derived according to the variation of the lubrication state, the variation of the contact temperature of the tooth surface with rotating speed is quite different from that calculated based on a friction coefficient which is set artificially. This leads to a new variation of the dynamic response of the gear-rotor system, and the method of stabilizing the operation of the system is put forward based on the optimization curve for the operation of the system. The results obtained in this paper will provide a reference for the study and design of a gear-rotor system in CAES.

Analysis of Shroud Cavity Leakage in a Radial Turbine for Optimal Operation in Compressed Air Energy Storage System

2020 ◽  
Vol 142 (7) ◽  
Author(s):  
Ziyi Shao ◽  
Wen Li ◽  
Xing Wang ◽  
Xuehui Zhang ◽  
Haisheng Chen
Keyword(s):  
High Pressure ◽  
Energy Storage ◽  
Storage System ◽  
Internal Flow ◽  
Energy Storage System ◽  
Optimal Operation ◽  
Compressed Air ◽  
Compressed Air Energy Storage ◽  
Rotating Speed ◽  
Radial Turbine

Abstract As an important energy generation device of the compressed air energy storage (CAES) system, the radial-inflow turbine with shrouded impeller is employed to avoid the leakage flow in the rotor, especially in the high-pressure stages. However, a lack of clarity in the leakage characteristics and their drivers still prevents a systematic approach to the efficient performance and proper design of the shrouded radial turbine. In the present work, the shroud cavity leakage of the shrouded radial turbine has been studied numerically. The physical quantity synergy is innovatively employed to research the internal flow field of the shroud cavity. It is found that the influence of high rotating speed on the seal leakage cannot be neglected, and the average reduced rate of seal leakage is found to be about 9.9% for the designed clearance. The leakage mass flow rate could be reduced by increasing the rotating speed or decreasing the seal clearance. The synergy angle is able to predict the flow resistance in shroud cavity very well. According to the volume-averaged synergy angle in the seal, the dimensionless seal clearance smaller than 1.5% in the shrouded radial turbine is recommended. Compared with the seal clearance in other high-pressure shrouded turbomachines, the current recommended clearance should be within a reasonable field.

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