Interstage difference of pressure pulsation in a three-stage electrical submersible pump

The balancing holes in centrifugal pumps with seals mounted in both suction and discharge sides are one of the approaches used by pump manufacturers to reduce the axial thrust. The balance hole diameter directly affects the axial force of the centrifugal pump. The flow characteristics in the balance chamber are closely related to the balance hole diameter. However, research is not very clear on the internal flow of the balanced chamber, due to the small axial and radial sizes and the complicated flow conditions in the chamber. In this paper, we analyzed the influence of the balance hole diameter on the liquid leakage rate, flow velocity, and vortex motion in the balance chamber. The results indicated that when the balance hole diameter was lower than the design value, the volume flow rate of leakage flow was proportional to the diameter. The liquid flow rate and vortex distribution rules in the balance chamber were mainly associated with the coeffect of radial leakage flow in the rear sealing ring interval and the axial balance hole leakage flow. The research has revealed the mechanisms of leakage flow of the balance chamber in the centrifugal pump and that this is of great significance for accurate calculation and balancing of the axial force.

Section: Introductionmentioning

confidence: 98%

Influence of Balance Hole Diameter on Leakage Flow of the Balance Chamber in a Centrifugal Pump

Dong

Chen

Sun

et al. 2021

“…Due to the complexity of unit structures and operating environment, the vibration signals collected often show strong nonstationary and time-varying characteristics, which make it difficult to extract the fault characteristics of units under the background of noise. Moreover, although the hydrodynamics of hydraulic machinery has been widely reported [4][5][6][7], the related diagnostic methods are seldom studied [8].On this basis, many time-frequency analysis methods have been proposed to extract signal characteristics. In these methods, EMD is a new adaptive decomposition method proposed in [9], which can adaptively decompose nonlinear and nonstationary signals without being disturbed by complex environment [10,11].…”

Section: Introductionmentioning

confidence: 99%

Research on Fault Feature Extraction of Hydropower Units Based on Adaptive Stochastic Resonance and Fourier Decomposition Method

Ren

Huang

Hu³

et al. 2021

In order to effectively extract the characteristics of nonstationary vibration signals from hydropower units under noise interference, an adaptive stochastic resonance and Fourier decomposition method (FDM) based on genetic algorithm (GA) are proposed in this paper. Firstly, GA is used to optimize the resonance parameters so that the signal can reach the optimal resonance and the signal-to-noise ratio (SNR) can be improved. Secondly, FDM is used to process the signal and the appropriate frequency band function is selected for reconstruction. Finally, Hilbert envelope demodulation analysis was performed on the reconstructed signal to obtain the fault characteristics from the envelope spectrum. In order to prove the effectiveness and superiority of the proposed method, comparative experiments are designed by using the simulated signal and the measured swing signal of a hydropower unit. The results show that this method can effectively remove the noise interference and improve the SNR and extract the characteristic frequency of the signal, which has the extensive engineering application value to the fault diagnosis of hydropower units.

“…As a new surface-treatment technology, high-pressure water-jet technology achieves material cutting and surface cleaning and polishing through the ultra-high impact kinetic energy of the water jet [1][2][3]. Because of its high efficiency, wide applicability, and environmental protection, water-jet technology has been used extensively in various fields [4][5][6][7], such as pumping, rock breaking, mining, ship cleaning and rust removal, and material cutting [8][9][10][11]. Significant progress has been made in the simulation of flow field [11][12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Water-Jet Erosion of Grade-A Ship Steel: Experimental Research

Cao

Zhang

Shi

et al. 2021

Self Cite

A water-jet erosion test was carried out on grade-A ship steel to study the interaction and erosion mechanism of the water jet on the steel surface. When the water jet impacted, a STSS-1 stress-detection module was used to collect the dynamic strain signal on the rear of the ship’s plate, and a scanning electron microscope, transmission electron microscope, X-ray diffractometer, and other equipment were used to analyze the microstructure and phase of the grade-A ship steel before impact. The surface morphology of the material after impact was studied and analyzed. The impact stress of the water jet on the grade-A steel was an alternating stress, and the jet pressure decayed in the radial direction. The material surface was fatigued under the action of the jet alternating stress. After the water-jet erosion, the central area of the grade-A steel was dominated by an elongated cementite hard phase, and the peripheral area had a pearlite structure. A model for the jet erosion and peeling of grade-A ship steel was established to clarify the mechanism of erosion by the water jet.