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Optimizing Multi-Row Cam Roller Bearing for Long Fatigue Life of Hydraulic Motors

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Chinese Journal of Mechanical Engineering 2024年第5期37卷 180-190页

作者： Yu Fang Qi Su Pengpeng Dong Yu Yang Bing Xu Chao Zhang Junhui Zhang State Key Laboratory of Fluid Power and Mechatronic Systems Department of Mechanical EngineeringZhejiang UniversityHangzhou 310027China Hangzhou Applied Acoustics Research institute Hangzhou 310027China Zenmax hydraulics Co. Ltd.Qinhuangdao 066000China

Cam-lobe radial-piston hydraulic motors are widely used as rotation driving units for various marine machinery owing to their ultrahigh output torque(more than 100 kN m).A multi-row cam roller bearing(MCRB)is the key component that directly determines the fatigue life of a cam-lobe radial-piston hydraulic ***,compact geometry and complex loads render MCRB susceptible to fatigue failure,highlighting the need for an optimized MCRB to achieve longer fatigue life and higher ***,this study proposes an innovative geometry optimization method for an MCRB to improve its fatigue *** this method,a quasi-static model was developed to calculate the load distribution,with the fatigue life of the MCRB calculated using both basic dynamic loading and load ***,a genetic algorithm was used to obtain the optimized geometry parameters,which significantly improved the fatigue life of the ***,a loading test was conducted on a hydraulic motor installed with both the initial and optimized MCRB to validate the effectiveness of the proposed optimization *** study provides a theoretical guideline for optimizing the design of MCRB,thereby increasing the fatigue life of hydraulic motors.

关键词： Hydraulic motor Cam roller bearing Fatigue life Geometry optimization Load distribution

Particle image velocimetry measurements of vortex structures in stilling basin of multi-horizontal submerged jets

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Journal of Hydrodynamics 2013年第4期25卷 556-563页

作者：陈剑刚张建民许唯临栗帅何小泷 State Key Laboratory of hydraulics and Mountain River Engineering Sichuan University institute of Mountain Hazards and Environment Chinese Academy of Sciences

Measurements of turbulent flow fields in a stilling basin of multi-horizontal submerged jets were made with the single- camera Particle Image Velocimetry （PIV）. The particle images were captured, processed, and subsequently used to characterize the flow in terms of the 2-D velocity and vorticity distributions. This study shows that the maximum close-to-bed velocity in the stilling basin is approximately reduced by 60%, comparing to the jet velocity at the outlet of orifices. The jet velocity is distributed evenly at the latter half of the stilling basin and the time-averaged velocity of the cross section is reduced by 77%-85%, comparing to the jet velocity at the outlet of orifices. These results show that the vortices with horizontal axes are continuously repeated during the form-merge-split-disappear process. The vertical vortices are continuously formed and disappeared, they appear randomly near the slab and intermittently reach the slab of the stilling basin. The range of these vortices is small. Vortices with horizontal axes and ver- tical vortices do not coincide in space and the vortices with horizontal axes only affect the position of the tail of the vertical vortices attached to the slab of the stilling basin.

关键词： multi-horizontal submerged jets Particle Image Velocimetry (PIV) vortex structure stilling basin hydraulic jump

Wave reflection, transmission and harmonics due to different submerged structures

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Acta Oceanologica Sinica 2000年第2期19卷 111-125页

作者： Gao Xueping1 Inouchi Kunimitsu2 Kakinuma Tadao3 (1. hydraulics institute, Faculty of Civil Engineering, Tianjin University, Tianjin 300072, China 2. Center for Cooperative Research and Development, Ehime University, 3 Bunkyo-cho, Matsuyama 790 - 8577, Japan 3. Nagasaki Comprehensive University, Aba-cho 536, Nagasaki 851 - 0193, Japan) hydraulics institute Faculty of Civil Engineering Tianjin University Tianjin 300072 China

Comparisons of wave reflection, transmission and harmonics due to different types of sub merged structures are investigated by a numerical method, the boundary-fitted coordinate (BFC) method. The types of submerged structures include a submerged horizontal plate, submerged breakwa ters (rectangular and trapezoidal) and a step-type structure (topography). First, the BFC method is ver ified by comparing the computed results with the experimental data, including wave surface elevations, reflected and transmitted wave heights, and amplitudes of higher harmonics, showing that the method is a reasonable one to predict wave deformations due to the submerged structures. Secondly, the wave sur face elevations and the higher harmonics over different submerged structures are compared. Thirdly, re flected and transmitted waves due to different submerged structures are investigated.

关键词： Harmonic wave reflected wave transmitted wave submerged structure boundary-fitted coordinate method

Experimental investigation of the optimization of stilling basin with shallowwater cushion used for low Froude number energy dissipation

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Journal of Hydrodynamics 2015年第4期27卷 522-529页

作者：李连侠廖华胜刘达蒋胜银 State Key Laboratory of hydraulics and Mountain River Engineering Sichuan University Guangdong Research institute of Water Resources and Hydropower Chengdu Municipal Engineering Design and Research institute

Energy dissipations induced by the hydraulic jump and the trajectory jet are the most widely known as the two dissipation modes at the downstream of flood discharging structures, which are often considered quite different even contradictory. However, such two energy dissipators can be used jointly and harmonically. In this paper, a new type of stilling basin with a shallow-water cushion and a triangular bottom deflector is proposed based on two different scale physical model tests of the flood discharging tunnel No.2 of Luding hydropower project. The experimental results show that the flow regime of the hydraulic jump in the presented stilling basin with bottom deflector enjoys a good and stable performance within a large range of flow rates and the energy dissipation rate is considerably high as compared to the conventional stilling basin even at a low Froude number. The results also indicate that the stilling basin with triangular bottom deflector has a better performance in improving the potential cavitation erosion according to the analysis of the pressure and the cavitation number compared to the trapezoidal one. The proposed new type of shallow-cushion stilling basin with a shallow-water cushion can be applied in similar energy dissipation projects with low Froude number and large range of flow rates.

关键词： stilling basin shallow-water cushion energy dissipation low Froude number bottom deflector

Numerical modeling of lock-exchange gravity/turbidity currents by a high-order upwinding combined compact difference scheme

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International Journal of Sediment Research 2019年第3期34卷 240-250页

作者： Liang Zhao Ching-Hao Yu Zhiguo He institute of Port Coastal and Offshore Engineering Ocean College Zhejiang University State Key Laboratory of hydraulics and Mountain River Engineering Sichuan University State Key Laboratory of Satellite Ocean Environment Dynamics The Second Institute of Oceanography State Oceanic Administration

This study presents two-dimensional direct numerical simulations for sediment-laden current with higher density propagating forward through a lighter ambient water. The incompressible Navier Stokes equations including the buoyancy force for the density difference between the light and heavy fluids are solved by a finite difference scheme based on a structured mesh. The concentration transport equations are used to explore such rich transport phenomena as gravity and turbidity currents. Within the framework of an Upwinding Combined Compact finite Difference(UCCD) scheme, rigorous determination of weighting coefficients underlies the modified equation analysis and the minimization of the numerical modified wavenumber. This sixth-order UCCD scheme is implemented in a four-point grid stencil to approximate advection and diffusion terms in the concentration transport equations and the first-order derivative terms in the Navier-Stokes equations, which can greatly enhance convective stability and increase dispersive accuracy at the same time. The initial discontinuous concentration field is smoothed by solving a newly proposed Heaviside function to prevent numerical instabilities and unreasonable concentration values. A two-step projection method is then applied to obtain the velocity field. The numerical algorithm shows a satisfying ability to capture the generation, development, and dissipation of the Kelvin-Helmholz instabilities and turbulent billows at the interface between the current and the ambient fluid. The simulation results also are compared with the data in published literatures and good agreements are found to prove that the present numerical model can well reproduce the propagation,particle deposition, and mixing processes of lock-exchange gravity and turbidity currents.

关键词： Gravity current Turbidity current Depth-resolving mathematical model Incompressible Navier-Stokes equations Upwinding Combined Compact Difference (UCCD) scheme

Effect of total dissolved gas supersaturated water on early life of David's schizothoracin (Schizothorax davidi)

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Journal of zhejiang University-Science B(Biomedicine & Biotechnology) 2013年第7期14卷 632-639页

作者： Rui-feng LIANG Bo LI Ke-feng LI You-cai TUO State Key Laboratory of hydraulics and Mountain River Engineering Sichuan University Changjiang River Scientific Research institute

The effect of total dissolved gas （TDG） supersaturation on fish living downstream of dams is one of the main ecological risks of high dam construction. A strategy for mitigating the negative effects is needed urgently since many high dams are under construction in the upper reaches of the Yangtze River in China. Experiments on the hatching process of David＇s schizothoracin were carried out and the results show that the hatching rate decreased with increasing TDG levels, and that most eggs hatched within a very short time in the higher TDG saturation groups. By using a stereomicroscope, damages to the head, yolk sac, body, anus, etc. were found in larvae which hatched in TDG supersaturated water. Results show that the lesion rate increased with increasing TDG levels. Furthermore, 7-d-old David＇s schizothoracin were exposed to TDG supersaturated water levels of 100%, 105%, 110%, 115%, 120%, 125%, 130%, 135%, and 140% for testing their tolerance to TDG supersaturation. We found that the median lethal concentrations （LC50） for 13, 14, 20, 35, 52, 73, and 96 h exposure were 138%, 138%, 134%, 130%, 129%, 128%, and 126%, respectively. The median lethal times （LTs0） were 7.49, 11.04, 19.25, and 35.38 h for exposure to water with TDG levels of 145%, 140%, 135%, and 130%, respectively.

关键词： Total dissolved gas (TDG) TDG supersaturation David's schizothoracin Hatch Larvae

The properties of dilute debris flow and hyper-concentrated flow in different flow regimes in open channels

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Journal of Mountain Science 2017年第9期14卷 1728-1738页

作者： LIU Yan WANG Hui-feng CHEN Hua-yong HU Kai-heng WANG Xie-kang State Key Laboratory of hydraulics and Mountain River Engineering Sichuan University institute of Mountain Hazards and Environment CAS

Particle Image Velocimetry(PIV) technique was used to test the analogues of hyperconcentrated flow and dilute debris flow in an open flume. Flow fields, velocity profiles and turbulent parameters were obtained under different conditions. Results show that the flow regime depends on coarse grain concentration. Slurry with high fine grain concentration but lacking of coarse grains behaves as a laminar flow. Dilute debris flows containing coarse grains are generally turbulent flows. Streamlines are parallel and velocity values are large in laminar flows. However, in turbulent flows the velocity diminishes in line with the intense mixing of liquid and eddies occurring. The velocity profiles of laminar flow accord with the parabolic distribution law. When the flow is in a transitional regime, velocity profiles deviate slightly from the parabolic law. Turbulent flow has an approximately uniform distribution of velocity and turbulent kinetic energy. The ratio of turbulent kinetic energy to the kinetic energy of time-averaged flow is the internal cause determining the flow regime: laminar flow(k/K1). Turbulent kinetic energy firstly increases with increasing coarse grain concentration and then decreases owing to the suppression of turbulence by the high concentration of coarse grains. This variation is also influenced by coarse grain size and channel slope. The results contribute to the modeling of debris flow and hyperconcentrated flow.

关键词： Hyper-concentrated flow Debris flow Flow regime Velocity profile Turbulent kinetic energy Open channel

Peaked abundance of Calanus sinicus earlier shifted in the Changjiang River (Yangtze River) estuary:a comparable study between 1959,2002 and 2005

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Acta Oceanologica Sinica 2011年第3期30卷 84-91页

作者： XU Zhaoli MA Zengling WU Yumei Key and Open Laboratory of Marine and estuary Fisheries （Ministry of Agriculture） East China Sea Fisheries Research Institute Chinese Academy of Fisheries Science Shanghai 200090 China

The sea surface temperature （SST） of the East China Sea （ECS） increased in the past decades, which may have a great impact on the ecosystem of the ECS, including the changes in planktonpopulation structure. In this paper, the changes in peaked abundance of Calanus sinicus in the Changjiang River （Yangtze River） estuary were compared between 1959 and 2002, based on the data collected from the seasonally oceanographic cruises and those performed in spring of 2005. It was much higher in spring compared with that in other seasons both in 1959 and 2002. Furthermore, in spring 2005, the time for occurrence and decrease of the peaked C. sinicus abundance advanced about one month, accompanying the increase in the sea surface water temperature （SST）. It peaked in June and decreased in July in 1959, however, in 2005, it peaked in May and attenuated sharply in early June. The earlier decrease of peaked C. sinicus abundance may further deteriorate the ecosystem in the Changjiang River estuary and north nearshore of the ECS.

关键词： Calanus sinicus East China Sea (ECS) temperature Changjiang River (Yangtze River) estuary zooplankton

The relation between distribution of zooplankton and salinity in the Changjiang estuary

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Chinese Journal of Oceanology and Limnology 2008年第2期26卷 178-185页

作者：高倩徐兆礼庄平 institute of Oceanology Chinese Academy of Sciences Key and Open Laboratory of Marine and estuary Fisheries Ministry of Agriculture of ChinaEast China Sea Fisheries Research InstituteChinese Academy of Fisheries Sciences

Seasonal netzplankton samples from stations in the Changjiang (Yangtze River) estuary were collected from May, 2004 to February, 2005. The dominant species and their contribution to the total zooplankton abundance were determined. Moreover, the relationship between the salinity and abundance was studied with stepwise linear regression. During the whole year, the salinity was positively correlated with the abundance, while the temperature, negatively. Linear regression analysis showed also a high positive correlation with salinity for total abundance in August and November, while in February and May, no obvious relations were found. The most abundant community was composed of neritic and brackish-water species. The North Passage (NP) (salinity estuary.

关键词： salinity Changjiang (Yangtze River) estuary zooplankton abundance dominant species