scholarly journals Fundamental study of seismic emission tomography in terms of fluid pressure fluctuations

Author(s):  
A. Watanabe ◽  
H. Mikada ◽  
J. Takekawa
2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Peixin Gao ◽  
Hongquan Qu ◽  
Yuanlin Zhang ◽  
Tao Yu ◽  
Jingyu Zhai

Pipeline systems in aircraft are subjected to both hydraulic pump pressure fluctuations and base excitation from the engine. This can cause fatigue failures due to excessive vibrations. Therefore, it is essential to investigate the vibration behavior of the pipeline system under multiexcitations. In this paper, experiments have been conducted to describe the hydraulic pipeline systems, in which fluid pressure excitation in pipeline is driven by the throttle valve, and the base excitation is produced by the shaker driven by a vibration controller. An improved model which includes fluid motion and base excitation is proposed. A numerical MOC-FEM approach which combined the coupling method of characteristics (MOC) and finite element method (FEM) is proposed to solve the equations. The results show that the current MOC-FEM method could predict the vibration characteristics of the pipeline with sufficient accuracy. Moreover, the pipeline under multiexcitations could produce an interesting beat phenomenon, and this dangerous phenomenon is investigated for its consequences from engineering point of view.


2015 ◽  
Vol 9 (1) ◽  
pp. 714-720 ◽  
Author(s):  
Xiang Kefeng ◽  
Yao Jin ◽  
Zeng Xiangwei

For studying the kinetic characteristics of passive shuttle check valve at the moment that it closes its valve core on the condition of high pressure differences, this paper first constructs the equation of motion of the valve core and twodimensional geometrical model by using computation fluid dynamics method, then with the help of the calculation method and physical model provided by Fluent software, employing the dynamic mesh and user-defined functions, simulates the unsteady flow in the valve core’s closing process under the different pressure fluctuations, and obtains the stress nephogram, the velocity vector diagram, the speed curve, and pressure curve of the interior flow field of the valve. The results show that the bigger the value of valve fluctuation is, the larger the fluid pressure that the valve core is subjected to, the openness of the core and the speed fluctuation of the core are, and that in the case of sudden decompression at the entrance, the core can be shut down quickly with the steady speed field and pressure field. The simulation results are conducive to the design and optimization of structure parameter of shuttle check valve.


Sign in / Sign up

Export Citation Format

Share Document