Papers by Keyword: Hydraulic Machinery

Abstract: Completed solid model of hydraulic mechanical power split CVT using Pro/E software basing on the transmission principle, achieved the whole transmission without interference assemble by the interference analysis and checking the gap. Carried on dynamics simulation analysis using ADAMS software, obtained the variation of plungers’ centroid and the bearing force in the rear end cover, it laid the theoretical foundation for subsequent experimental analysis.

Abstract: The paper attempts to assess the erosive potential of cavitation bubbles in unsteady flow of liquid over a prismatic hydrofoil using two-way coupling of the URANS and the Rayleigh-Plesset equations. The erosive potential of the cavitating flow is evaluated from the energy dissipated during the collapses of imploding cavitation bubbles near the solid surface of the hydrofoil. The bubbles are assumed spherical and the phase slip is neglected. Bubble fission is modelled using a simple break-up model. The interaction between bubbles is considered by superposing the pressure change due to pressure waves generated by collapsing bubbles and propagated in the computational domain over the local pressure in the liquid (external to the bubble). The rate of erosion of the solid material is not studied in this work. The flow is analysed using the in-house three-dimensional solver for unsteady turbulent flow with bubble dynamics. The results are demonstrated on the NACA 2412 hydrofoil with the incidence angle of 8 degrees and the cavitation number 1.37, which corresponds to the regime of oscillating partial cavity with periodic shedding of bubble cloud downstream of the cavity.

Abstract: Shaft fault is the most common fault for hydraulic machinery. In this paper, wavelet packet energy spectrum analysis method was used for multi frequency bands division of shaft monitoring signals. The variable bands frequency energy can construct feature vectors needed for fault diagnosis based on support vector machine, by integrating the procedure of wavelet packet analysis method and online monitoring technology, feature can be extracted in real time, and it make possible for real-time fault diagnosis and prediction of hydraulic machine.

Abstract: With the operation of giant unit of hydroelectric plant represented by the Three Gorges Power Station, the vibration problem of hydraulic turbine set unit is increasingly outstanding, especially the vibration of structure induced by pressure fluctuation. In order to guarantee the normal operation of unit, model test is more important in the respect of predicting performance, increasing stability and avoiding vibration. The pressure fluctuation measurement system based on LabVIEW according to pressure fluctuation model test was designed in this paper. The system is applied to the hydro-turbine model test-bed of HEC so that real-time automatic test with the characteristics of high stability and precision is implemented successfully. It plays an important role in respects of mastering the operation characteristics collecting and analyzing pressure fluctuation signals. Moreover it is meaningful to the hydraulic engineering.

Abstract: Based on the good function for 3D modeling of Pro/E software, 3D geometry modeling for the entire flow passage of HLA351 which is the Francis turbine with long and short blades was realized by means of a series of methods of drawing from inside to outside, drawing from top to bottom, drawing lines from points, drawing surfaces from lines, and finally getting body from surfaces, so as to provide a reliable foundation for the future CFD calculation and performance prediction.

Abstract: Engineering ceramics have a high application potential for wear-protection of different equipment used for electric power generating, mining and mineral industries. The ZTA (zirconia toughened alumina) and alumina (92%, 95%) have been prepared. Effects of varying the impact velocity and volume content of erodent particle and erosive time are investigated. Scanning electron microscopic examination of the eroded ceramic surfaces provides insights into the erosive wear mechanisms. The material removal processes include chipping out of lateral cracks caused by impact of the erodent particles, grain boundary cracking and grain pull out, as well as plastic deformation caused by the repeated sliding and impact of the particles.