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Effect of impeller reflux balance holes on pressure and axial force of centrifugal pump

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Journal of Central South University 2015年第5期22卷 1695-1706页

作者：曹卫东代珣胡啟祥 Technical and Research Center of Fluid Machinery Engineering Jiangsu University

The size of impeller reflux holes for centrifugal pump has influence on the pressure distribution of front and rear shrouds and rear pump chamber, as well as energy characteristics of whole pump and axial force. Low specific-speed centrifugal pump with Q=12.5 m3/h, H=60 m, n=2950 r/min was selected to be designed with eight axial reflux balance holes with 4.5 mm in diameter. The simulated Q-H curve and net positive suction head(NPSH) were in good agreement with experimental results, which illustrated that centrifugal pump with axial reflux balance holes was superior in the cavitation characteristic; however, it showed to little superiority in head and efficiency. The pressure in rear pump chamber at 0.6 times rate flow is 29.36% of pressure difference between outlet and inlet, which reduces to 29.10% at rate flow and 28.33% at 1.4 times rate flow. As the whole, the pressure distribution on front and rear shrouds from simulation results is not a standard parabola, and axial force decreases as flow rate increases. Radical reflux balance holes chosen to be 5.2 mm and 5.9 mm in diameter were further designed with other hydraulic parts unchanged. With structural grids adopted for total flow field, contrast numerical simulation on internal flow characteristics was conducted based on momentum equations and standard turbulence model(κ-ε). It is found that axial force of pump with radical reflux balance holes of5.2 mm and 5.9 mm in diameter is significantly less than that with radical reflux balance holes of 4.5 mm in diameter. Better axial force balance is obtained as the ratio of area of reflux balance holes and area of sealing ring exceeds 6.

关键词： centrifugal pump low specific-speed radical reflux balance holes numerical simulation pressure gradient axial force

Horizontal dynamic response of a large-diameter pipe pile considering the second-order effect of axial force

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Earthquake Engineering and Engineering Vibration 2018年第3期17卷 567-579页

作者： Luan Lubao Ding Xuanming Zhou Wei Zheng Changjie Qu Liming Key Laboratory of New Technology for Construction of Cities in Mountain Area College of Civil EngineeringChongqing UniversityChongqing 400045China Powerchina Chengdu Engineering Corporation Limited Chengdu 611130China

The second-order effect of axial force on horizontal vibrating characteristics of a large-diameter pipe pile is theoretically *** equations of the pile-soil system are established based on *** wave equations of soil are decoupled through differential transformation and variable ***,expressions of soil displacements and horizontal resistances can be *** analytical solution of the pile is derived based on continuity conditions between the pile and soil,subsequently from which expressions of the complex impedances are *** are carried out to examine the second-order effect of axial force on the horizontal vibrating behavior of the pipe *** conclusions can be summarized as follows： stiffness and damping factors are decreased with the application of axial force on the pile head; distributions of the pile horizontal displacement and rotation angle are regenerated due to the second-order effect of the applied axial force; and redistributions of the bending moment and shearing force occur due to the second-order effect of the applied axial force.

关键词： axial force second-order effect horizontal vibration pipe pile analytical solution

Semi-analytic solution of Eringen's two-phase local/nonlocal model for Euler-Bernoulli beam with axial force

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Applied Mathematics and Mechanics(English Edition) 2018年第12期39卷 1805-1824页

作者： Licheng MENG Dajun ZOU Huan LAI Zili GUO Xianzhong HE Zhijun XIE Cunfa GAO Facility Design and Instrumentation Institute China Aerodynamics Research and Development Center State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and Astronautics

Eringen’s two-phase local/nonlocal model is applied to an Euler-Bernoulli nanobeam considering the bending-induced axial force, where the contribution of the axial force to bending moment is calculated on the deformed state. Basic equations for the corresponding one-dimensional beam problem are obtained by degenerating from the three-dimensional nonlocal elastic equations. Semi-analytic solutions are then presented for a clamped-clamped beam subject to a concentrated force and a uniformly distributed load, respectively. Except for the traditional essential boundary conditions and those required to be satisfied by transferring an integral equation to its equivalent differential form, additional boundary conditions are needed and should be chosen with great caution, since numerical results reveal that non-unique solutions might exist for a nonlinear problem if inappropriate boundary conditions are used. The validity of the solutions is examined by plotting both sides of the original integro-differential governing equation of deflection and studying the error between both sides. Besides, an increase in the internal characteristic length would cause an increase in the deflection and axial force of the beam.

关键词： nonlocal elasticity internal characteristic length size effect nanobeam axial force unique solution

Mobility matrix of a weakly coupled parallel multi-DIM isolator based on axial force solution

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High Technology Letters 2020年第3期26卷 335-341页

作者： Li Desheng Yu Jiangtao Huang Baowang Li Zhanxian Wang Zhijun College of Mechanical Engineering North China University of Science and TechnologyTangshan 063210P.R.China

A mobility matrix modeling strategy based on axial force solution for a weakly coupled parallel multi-dimentional(multi-DIM)isolator is *** power flow and transmissibility through the isolator are derived from the mob... 详细信息

关键词： mobility matrix weak-coupling parallel multi-dimentional(multi-DIM)isolator axial force mobility power flow

A Combined-Power Model for the Distribution of axial force in Shaft Anchor along Its Length

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Journal of China University of Geosciences 2006年第1期17卷 89-94页

作者：卫军周锡武朱玉罗昕 Civil Engineering Department Huazhong University of Science and Technology Wuhan430074 China Civil Engineering Department Huazhong University of Science and Technology Wuhan430074 ChinaChina Communications Second Highway Survey Design and Research Institute Wuhan430052 China

The theoretical results of axial force distribution models differ greatly from tests because of the complication of the rock type material. A three-parameter combined-power model is proposed by curves fitting the test data recorded from the pull tests on anchoring bars used in different engineering projects. Based on the comparison of the mechanical characteristics of shaft anchors and prestressed tendons, a two-parameter combined-power function model for prestressed tendons is proposed. The bounded length derived from the model and the suggested values of the parameters are also proposed. Compared with the Gaussian model, the three-parameter combined-power model is more precise and simple in expression. Results also suggest that the bounded length calculated from the average stress method is not safe enough.

关键词： axial force prestress tendon bounded length combined-power model Gaussian model

axial force measurement for esophageal function testing

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World Journal of Gastroenterology 2009年第2期15卷 139-143页

作者： Flemming H Gravesen Peter Funch-Jensen Hans Gregersen Asbjφrn Mohr Drewes Mech-Sense Department of Gastroenterology Aalborg Hospital Aalborg Denmark Center for Sensory-Motor Interaction (SMI) Department of Health Science and Technology Aalborg University DK-9000 Aalborg Denmark Department of Surgical Gastroenterology L rhus University Hospital rhus Denmark

The esophagus serves to transport food and fluid from the pharynx to the stomach. Manometry has been the "golden standard" for the diagnosis of esophageal motility diseases for many decades. Hence, esophageal function is normally evaluated by means of manometry even though it reflects the squeeze force (force in radial direction) whereas the bolus moves along the length of esophagus in a distal direction. force measurements in the longitudinal (axial) direction provide a more direct measure of esophageal transport function. The technique used to record axial force has developed from external force transducers over in-vivo strain gauges of various sizes to electrical impedance based measurements. The amplitude and duration of the axial force has been shown to be as reliable as manometry. Normal, as well as abnormal, manometric recordings occur with normal bolus transit, which have been documented using imaging modalities such as radiography and scintigraphy. This inconsistency using manometry has also been documented by axial force recordings. This underlines the lack of information when diagnostics are based on manometry alone. Increasing the volume of a bag mounted on a probe with combined axial force and manometry recordings showed that axial force amplitude increased by 130% in contrast to an increase of 30% using manometry. Using axial force in combination with manometry provides a more complete picture of esophageal motility, and the current paper outlines the advantages of using this method.

关键词： axial force Traction force Manometry Motility Peristalsis Esophageal function

Analysis of axial force of double circular arc helical gear hydraulic pump and design of its balancing device

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Journal of Central South University 2021年第2期28卷 418-428页

作者： WU Yi-fei GE Pei-qi BI Wen-bo School of Mechanical Engineering Shandong UniversityJinan 250061China Key Laboratory of High Efficiency and Clean Mechanical Manufacture(Ministry of Education) Shandong UniversityJinan 250061China

In view of the axial force produced in the working process of double arc helical gear hydraulic pump,the theory of differential equation of curve and curved surface was utilized so that the calculation formula of axial force was obtained and the relationship between the axial force and structure parameters of gears was *** order to balance the axial force,the pressure oil in the high pressure area was introduced into the end face of the plunger to press the plunger against the gear shaft,and the hydrostatic bearing whose type is plunger at the end of the shaft was *** order to verify the balance effect of axial force,the leakage owing to end clearance and volume efficiency of gear hydraulic pump before and after the balancing process was *** paper provides a new analysis idea and balance scheme for the axial force produced in the working process of the double arc helical gear hydraulic pump,which can reduce the leakage owing to end clearance caused by the axial force and improve the volume efficiency of the gear hydraulic pump.

关键词： double arc helical gear gear hydraulic pump axial force hydrostatic bearing

Effect of Process Parameters on Tensile Strength of Friction Stir Welded Cast LM6 Aluminium Alloy Joints

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Journal of Materials Science & Technology 2009年第5期25卷 655-664页

作者： M.Jayaraman R.Sivasubramanian V.Balasubramanian Department of Mechatronics Engineering Kongu Engineering CollegeErodeTamil NaduIndia Department of Mechanical Engineering Coimbatore Institute of TechnologyCoimbatoreTamil NaduIndia Centre for Materials Joining&Research(CEMAJOR) Department of Manufacturing EngineeringAnnamalai UniversityAnnamalainagarTamil NaduIndia

This paper reports the effect of friction stir welding （FSW） process parameters on tensile strength of cast LM6 aluminium alloy. Joints were made by using different combinations of tool rotation speed, welding speed and axial force each at four levels. The quality of weld zone was investigated using macrostructure and microstructure analysis. Tensile strength of the joints were evaluated and correlated with the weld zone hardness and microstructure. The joint fabricated using a rotational speed of 900 r/min, a welding speed of 75 mm/min and an axial force of 3 kN showed superior tensile strength compared with other joints. The tensile strength and microhardness of the welded joints for the optimum conditions were 166 MPa and 64.8 Hv respectively.

关键词： LM6 aluminium alloy Friction stir welding Tool rotation speed Welding speed axial force Tensile strength

A destructive field study on the behavior of piles under tension and compression

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2011年第4期12卷 291-300页

作者： Zhong-miao ZHANG Qian-qing ZHANG Feng YU MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering Zhejiang University Hangzhou 310058 China Institute of Geotechnieal Engineering Zhejiang University Hangzhou 310058 China School of Civil Engineering and Architecture Zhejiang Sci-Tech University Hangzhou 310018 China

This paper involves a series of destructive full-scale load tests on long bored piles instrumented with strain gauges along the shafts,including two compression and two tension loading *** load-displacement response,axial force,skin friction,and the thresholds of the slip displacement for fully mobilizing the skin resistances in different soils are ***,the theoretical solution for estimating the pile tip settlement under compression was adopted to analyze the test *** was found that the measured skin frictions for the piles under compression were about 6% to 42% higher than the estimated values of the cone penetration tests(CPTs),whereas the measured skin frictions in the uplift cases were about 16% to 50% smaller than the estimated *** addition,the average limited skin frictions for the tension piles were about 0.36 to 0.78 times the average ultimate skin frictions for the piles under *** also can be indicated that the skin friction along the pile depth approached the limited state,and decreased from a peak value with increasing loads.

关键词： Destructive full-scale test Load-displacement response axial force Pile-soil relative displacement Skin friction