air film
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2022 ◽  
Author(s):  
Takashi Miyashita ◽  
Hideto Takasawa ◽  
Yusuke Takahashi ◽  
Nobuyuki Oshima ◽  
Lars Steffens ◽  
...  
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2021 ◽  
Vol 10 (1) ◽  
pp. 39
Author(s):  
Yao Shi ◽  
Jinyi Ren ◽  
Shan Gao ◽  
Guang Pan

In order to study the influence of pressure-equalizing exhaust at the shoulder of a submarine-launched vehicle on the surface hydrodynamic characteristics, this paper establishes a numerical calculation method based on the VOF multiphase flow model, the standard RNG turbulence model and the overset mesh technology; the method compares the fusion characteristics of the air film at the shoulder of the underwater vehicle, as well as the distribution of surface pressure along the vehicle’s axial direction. The results show that the approximate isobaric zone derived from air film fusion can greatly improve the hydrodynamic characteristics of the vehicle, and the number of venting holes determines the circumferential fusion time of the air film. The greater the number of venting holes, the sooner circumferential fusion starts.


Author(s):  
Guoda Chen ◽  
Qi Lu ◽  
Yifan Ge ◽  
Wei Zhang

This paper studied the air film pressure field (AFPF) characteristics of aerostatic thrust bearing, in which we proposed the measurement equipment for the 2D AFPF and successfully verified the theoretical simulation results. The experimental results agreed well with the theoretical results. However, in the area between the distribution circle of orifice to the air film outlet boundary, the experimental air film pressure (AFP) was slightly higher than the theoretical one. While for the area between the distribution circle of orifice and the center of the bearing, it showed the opposite law. Besides, the increase ratio of the AFP was close to that of the external load with its increase.


2021 ◽  
pp. 1-42
Author(s):  
Hui Zhuang ◽  
Jianguo Ding ◽  
Peng Chen ◽  
Yu Chang ◽  
Xiaoyun Zeng ◽  
...  

Abstract The damped mass-spring model is often employed for the dynamic modeling and vibration analysis of aerostatic bearing systems by taking the air film as equivalent springs. However, the stiffness and damping of the air film are frequency-dependent, making the commonly used approach of taking static stiffness or fixed value as the spring coefficient no longer applicable for a bearing subject to a complex external force containing different frequencies. To address this issue, this paper develops the damped mass-spring model for the aerostatic thrust bearing considering the frequency-varying stiffness and damping by means of the linear superposition method. It indicates that the air bearing is still a linear system despite the frequency-dependent character of dynamic coefficients because the bearing vibration satisfies the superposition principle. The improved dynamic modeling approach is able to accurately and efficiently predict the overall dynamic response of the thrust plate when the it is subjected to a multi-frequency vibration. In solving the overall dynamic response, the stiffness and damping associated with the responses of the transient part and steady part correspond to the natural vibration frequency and external disturbance frequencies, respectively. The feasibility and accuracy of the improved modeling approach are partly or completely verified by the direct trajectory calculation method, the CFD dynamic mesh simulation and a modal test. The proposed modeling method provides an effective way for the vibration analysis of air bearings, and in the meantime avoids the possible numerical errors caused by the traditional modeling approach.


2021 ◽  
Vol 33 (9) ◽  
pp. 092107
Author(s):  
Zunru Fu ◽  
Haichuan Jin ◽  
Jun Zhang ◽  
Tianyou Xue ◽  
Dongsheng Wen

2021 ◽  
Vol 33 (9) ◽  
pp. 092110
Author(s):  
Lige Zhang ◽  
Tejaswi Soori ◽  
Arif Rokoni ◽  
Allison Kaminski ◽  
Ying Sun

2021 ◽  
Vol 23 (3) ◽  
pp. 540-547
Author(s):  
Paweł Zdziebko ◽  
Adam Martowicz

Gas foil bearings belong to the group of slide bearings and are used in devices in which operation at high rotational speeds of the shafts are of key importance, e.g., in gas turbines. The air film developed on the surface of the bearing’s top foil allows this structural component to be separated from the shaft. This ensures a non-contact operation of the bearing. In the case of the mentioned type of bearings, their resultant operational properties are influenced by both thermal and mechanical phenomena. The current work presents a model of a gas foil bearing developed making use of the Finite Element Method. The model takes into account thermomechanical couplings which are necessary for the correct simulation of the operation of physical components of the modeled system. The paper reports the results of numerical analyzes conducted for the elaborated model as well as the relevant conclusions concerning thermomechanical couplings present in gas foil bearings. The method for the experimental identification of the temperature and strain fields in the bearing’s top foil proposed to validate the numerical model is also presented.


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