Experimental and Numerical Investigations of Vibration Characteristics Induced by Pressure Fluctuations in a Parallel Operating Pumping System

2021 ◽  
Vol 147 (7) ◽  
Author(s):  
Yongshun Zeng ◽  
Zhifeng Yao ◽  
Fujun Wang ◽  
Ruofu Xiao ◽  
Chenglian He
Keyword(s):  
Pressure Fluctuations ◽  
Vibration Characteristics ◽  
Numerical Investigations ◽  
Pumping System

scholarly journals Numerical investigations of the energy performance and pressure fluctuations for a waterjet pump in a non-uniform inflow

2020 ◽  
Vol 153 ◽  
pp. 1042-1052 ◽  
Author(s):  
Xianwu Luo ◽  
Weixiang Ye ◽  
Renfang Huang ◽  
Yiwei Wang ◽  
Tezhuan Du ◽  
...  
Keyword(s):  
Pressure Fluctuations ◽  
Energy Performance ◽  
Numerical Investigations ◽  
Waterjet Pump

Fundamental Analysis on Rotor-Stator Interaction in a Diffuser Pump by Vortex Method

2001 ◽  
Vol 123 (4) ◽  
pp. 737-747 ◽  
Author(s):  
H. Wang ◽  
H. Tsukamoto
Keyword(s):  
Numerical Solutions ◽  
Pressure Fluctuations ◽  
Vortex Method ◽  
Solid Boundary ◽  
Vaned Diffuser ◽  
Unsteady Pressure ◽  
Pumping System ◽  
Rotor Stator Interaction ◽  
The Stability ◽  
Stability And Accuracy

A two-dimensional unsteady flow was calculated within a whole stage of a diffuser pump to investigate pressure fluctuations due to the interaction between impeller and diffuser vanes by using the vortex method, in which vortices shedding from solid boundary were determined by the basic governing equation. The Petrov-Galerkin Method was applied to yield the solutions that satisfy the boundary conditions in an integral sense, and it improved the stability and accuracy of the numerical solutions greatly. A new scheme was also proposed to improve the unsteady pressure evaluation by a boundary integration method in the rotor-stator interaction problem. Moreover, for a more realistic prediction of the pressure fluctuations, the inlet flow was supposed to change with time so that pumping system may balance. The calculated time-varying flow rate, total hydraulic head rise and pressure fluctuations in the vaned diffuser passage, were compared with the measured and calculated ones by other methods. Calculated unsteady pressure fluctuations in the vaned diffuser passage showed good agreement with the experimental data and the CFD calculated ones.

scholarly journals Comparative Analysis of Monitoring Methods for Vortex-induced Vibration of Multistage Pressure Reducing Valves

2021 ◽  
Author(s):  
Dongtao Xu ◽  
Ge Chang-rong ◽  
Li Ying ◽  
Liu Yue-juan
Keyword(s):  
Comparative Analysis ◽  
Vortex Shedding ◽  
Pressure Fluctuation ◽  
Lift Coefficient ◽  
Pressure Fluctuations ◽  
Vibration Characteristics ◽  
Monitoring Methods ◽  
Vortex Induced Vibration ◽  
Main Frequency ◽  
Superposition Effect

Abstract In this paper, a multistage pressure reducing valve is presented. The main frequency of vortex-induced vibration is evaluated by monitoring the lift coefficient during vortex shedding and the pressure fluctuation formed after vortex shedding in the flow field. By comparative analysis of two different methods, the number of vortices is relatively small at small openings. Due to the limitations of the location and quantity of monitoring points, accurately locating the most active position where pressure fluctuation occurs is difficult. Monitoring the lift coefficient is more suitable to evaluate the main frequency of vortex-induced vibration. At medium and large openings, due to the increase in the number of vortices, the superposition effect of the pressure fluctuation and the influence of the flow channel shape is more obvious. Monitoring the pressure fluctuation is more appropriate to evaluate the main frequency of vortex-induced vibration the valve. Therefore, a combination of the two methods can more accurately evaluate the vortex-induced vibration characteristics of the valve. When monitoring pressure fluctuation, the position and number of monitoring points directly affect the evaluation accuracy. The pressure fluctuations around the outlet and the multilayer sleeve are more active. It is more meaningful to monitor the pressure fluctuation at these points. The main frequency of the pressure fluctuation at these points better reflects the vortex-induced vibration characteristics of the valve.

The external characteristics and pressure fluctuations of a two-stage pneumatic-controlled pumping system

1980 ◽  
Vol 16 (12) ◽  
pp. 710-713
Author(s):  
S. V. Lovchev ◽  
F. M. Mir-Kasimov ◽  
E. P. Moroz ◽  
L. I. Sokov
Keyword(s):  
Pressure Fluctuations ◽  
Two Stage ◽  
Pumping System ◽  
External Characteristics

Vacuum System to Minimize the Specimen Contamination of High-Performance EM

1977 ◽  
Vol 35 ◽  
pp. 68-69
Author(s):  
N. Yoshimura ◽  
K. Shirota ◽  
T. Etoh
Keyword(s):  
Electron Microscope ◽  
High Speed ◽  
High Performance ◽  
High Vacuum ◽  
Vacuum System ◽  
Pump System ◽  
Pumping System ◽  
Diffusion Pump ◽  
Almost All ◽  
Cascade Type

One of the most important requirements for a high-performance EM, especially an analytical EM using a fine beam probe, is to prevent specimen contamination by providing a clean high vacuum in the vicinity of the specimen. However, in almost all commercial EMs, the pressure in the vicinity of the specimen under observation is usually more than ten times higher than the pressure measured at the punping line. The EM column inevitably requires the use of greased Viton O-rings for fine movement, and specimens and films need to be exchanged frequently and several attachments may also be exchanged. For these reasons, a high speed pumping system, as well as a clean vacuum system, is now required. A newly developed electron microscope, the JEM-100CX features clean high vacuum in the vicinity of the specimen, realized by the use of a CASCADE type diffusion pump system which has been essentially improved over its predeces- sorD employed on the JEM-100C.

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