scholarly journals Influence of Bionic Pit Structure on Friction and Sealing Performance of Reciprocating Plunger

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Tianyu Gao ◽  
Bo Su ◽  
Lei Jiang ◽  
Qian Cong
Keyword(s):  
Reduction Rate ◽  
Frictional Resistance ◽  
Lubricating Oil ◽  
Element Analysis ◽  
Friction Resistance ◽  
Sealing Performance ◽  
Maximum Drag Reduction ◽  
Lubrication Condition ◽  
Bionic Structure ◽  
Oil Film Pressure

A new kind of pit-shaped bionic plunger proposes to reduce the frictional resistance of the reciprocating plunger and improve its sealing performance. According to the dorsal pore of earthworm, the bionic pit structure with different parameters designed and processed. The friction resistance test, observation test, and finite element analysis carried out. The results show that the bionic pit structure can improve the lubrication condition of the plunger surface and reduce the frictional resistance with a maximum drag reduction rate of 14.32%. The pit-shaped bionic structure can increase the storage of lubricating oil, intercept the surface streamline, and decrease the flow rate. The bionic plungers’ mean contact pressure and oil film pressure increased significantly.

Effect of Bionic Concave Surface to the Drag Reduction Performance of Cylinder Sealing Ring

2014 ◽  
Vol 1055 ◽  
pp. 152-156 ◽  
Author(s):  
Gang Zhao ◽  
Fang Li ◽  
Wei Xin Liu ◽  
Jian Ying Zhao ◽  
Hong Shi Bi
Keyword(s):  
Drag Reduction ◽  
Reduction Rate ◽  
Cylinder Block ◽  
Lubricating Oil ◽  
Concave Surface ◽  
Movement Speed ◽  
Piston Velocity ◽  
Friction Resistance ◽  
Sealing Ring ◽  
Maximum Drag Reduction

According to the problem of large friction resistance exists between the sealing ring and the cylinder block when the piston cylinder works, the drag reduction technology of bionic concave surface was applied in the sealing ring. By building a drag reduction motion model of sealing ring with concave surface of triangular arrangement, the effect of drag reduction performance decided by concave diameter and piston velocity was studied with the method of numerical simulation. The results show that: when the piston velocity is fixed, the maximum drag reduction rate can be achieved with the concave diameter is 1.5mm, and the maximum drag reduction rate is 15.72%. Meanwhile when the diameter of the concave is fixed, the drag reduction rate increased gradually with the increase of initial speed, the drag reducing effect is best at the speed of 0.6m/s. In the process of piston movement, lubricating oil in concave shakes, and makes the lubricating oil flow to the inside wall of cylinder, which play the role of lubrication, so as to achieve the effect of reducing friction and increasing the movement speed of piston.

Research on Drag Reduction Performance of Bionic Shark Gill Jet Surface

2014 ◽  
Vol 654 ◽  
pp. 57-60 ◽  
Author(s):  
Zhao Gang ◽  
Fang Li ◽  
Wei Xin Liu ◽  
Ming Ming Liu ◽  
Hong Shi Bi
Keyword(s):  
Numerical Simulation ◽  
Boundary Layer ◽  
Drag Reduction ◽  
Fluid Velocity ◽  
Reduction Rate ◽  
Frictional Resistance ◽  
Normal Velocity ◽  
Main Field ◽  
Maximum Drag Reduction ◽  
Pressure Resistance

According to the problem of bionic shark gill jet can reduce friction on shark surface, a model of bionic jet surface was established based on shark surface was analyzed by measurements, and its numerical simulation was processed by using RNG k-ε turbulence model. The results show that: the gill jet can reduce frictional resistance on shark surface, and the best drag reduction can be got when the speed of main field is 5m/s, furthermore the maximum drag reduction rate can be up to 17.15%. The pressure of jet hole upstream is reduced which due to the barrier to the facing fluid by the jet, so that the pressure resistance of jet surface is reduced as well. Besides, jet fluid is blocked in the boundary layer by mainstream fluid, which caused the fluid velocity of jet hole downstream is reduced, the thickness of boundary layer is increased, and the normal velocity gradient of wall is reduced, so as to achieve the effect of drag reduction.

A Study of the Sealing Performance of a New High-Pressure Cone Valve for Deep-Sea Gas-Tight Water Samplers

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Shi-Jun Wu ◽  
Can-Jun Yang ◽  
Ying Chen ◽  
Yan-Qing Xie
Keyword(s):  
Finite Element Analysis ◽  
High Pressure ◽  
Deep Sea ◽  
Hydrothermal Fluid ◽  
Contact Model ◽  
Element Analysis ◽  
Sea Trial ◽  
Sealing Performance ◽  
Pressure Cone ◽  
Gas Tight

The cone valve plays an important role in high-pressure sealing applications. In this paper, a new high-pressure cone valve, based on the titanium alloy poppet-to-polyetheretherketone seat sealing structure, is proposed for deep-sea gas-tight water samplers. In order to study the sealing performance of the new valve, both the conforming poppet-seat contact model and the nonconforming poppet-seat contact model were evaluated. Finite element analysis based on the two models was performed and validated by experiments. The results indicate that the nonconforming poppet-seat contact model has a better sealing performance than the conforming poppet-seat contact model. The new cone valve also was applied in a gas-tight hydrothermal fluid sampler and successfully tested in a sea trial during the KNOX18RR cruise from 9 July to 12 August 2008.

Modeling and experimental research on engaging characteristics of wet clutch

2019 ◽  
Vol 71 (1) ◽  
pp. 94-101 ◽  
Author(s):  
Yanzhong Wang ◽  
Yuan Li ◽  
Yang Liu ◽  
Wei Zhang
Keyword(s):  
Contact Surface ◽  
Hydrodynamic Lubrication ◽  
Load Capacity ◽  
Lubricating Oil ◽  
Centrifugal Effect ◽  
Element Analysis ◽  
Content Type ◽  
Clutch Engagement ◽  
Wet Clutch ◽  
Engagement Process

PurposeTo gain in-depth understandings of engaging characteristics, the purpose of this paper is to improve the model of wet clutches to predict the transmitted torque during the engagement process.Design/methodology/approachThe model of wet clutch during the engagement process took main factors into account, such as the centrifugal effect of lubricant, permeability of friction material, slippage factor of lubricant on contact surface and roughness of contact surface. Reynolds’ equation was derived to describe the hydrodynamic lubrication characteristics of lubricant film between the friction plate and the separated plate, and an elastic-plastic model of the rough surfaces contact based on the finite element analysis was used to indicate the loading force and friction torque of the contact surface.FindingsThe dynamic characteristics of wet clutch engagement time, relative speed, hydrodynamic lubrication of lubricating oil, rough surface contact load capacity and transfer torque can be obtained by the wet clutch engagement model. And the influence of the groove shape and depth on the engaging characteristics is also analyzed.Originality/valueThe mathematical model of the wet clutch during the engagement process can be used to predict the engaging characteristics of the wet clutch which could be useful to the design of the wet clutch.

scholarly journals PENGARUH DIAMETER TIANG TERHADAP TAHANAN GESEK TIANG DALAM TANAH LEMPUNG

2019 ◽  
Vol 1 (3) ◽  
pp. 219-224
Author(s):  
Andikanoza Pradiptiya ◽  
A’isyah Salimah
Keyword(s):  
Pile Foundation ◽  
Structural Damage ◽  
Tensile Load ◽  
Frictional Resistance ◽  
Test Method ◽  
Scale Model ◽  
Friction Resistance ◽  
Average Value ◽  
Constant Rate ◽  
Pile Model

AbstractSome buildings impose limits on the foundation displacement that occur with relatively small values so as not to cause structural damage. The test method used was to make a model test box as a testing medium by simulating the actual model into the form of a scale model. The study was conducted using a single pile foundation with reduced scale, made of concrete with a diameter of 0.02 m, 0.03 m, 0.04 m and the length of each pile was 0.4 m. The pile model was mounted by pressing into the clay that had been compacted in the test box and then given a tensile load which refers to ASTM D3689-07 procedure E (Constant Rate of Uplift Test). Mobilization of pile friction resistance at critical displacement determined the frictional resistance of the ultimate pile units. The test results showed that the greater the diameter of the pile, the frictional resistance of the ultimate pile units would increase. The increase in frictional resistance of the ultimate pile units showed an average value of around 17.1%.Keywords : Pile foundation, Pile diameter, Friction resistance.AbstrakMeningkatnya pembangunan hunian mengakibatkan naiknya permintaan akan batako, hal ini tentunya Beberapa konstruksi bangunan memberikan batasan kepada perpindahan tiang yang terjadi dengan nilai yang relatif kecil supaya tidak menyebabkan kerusakan struktur. Metode uji yang dipakai adalah membuat box uji model sebagai media pengujian, dengan mensimulasikan model yang sebenarnya ke dalam bentuk model skala. Penelitian dilakukan menggunakan model pondasi tiang tunggal penampang lingkaran lingkaran skala tereduksi yang terbuat dari beton dengan diameter 0,02 m, 0,03 m, 0,04 m dan panjang  masing-masing tiang adalah 0,4 m. Model tiang dipasang dengan cara ditekan pada tanah lempung yang sudah dipadatkan dalam box uji kemudian diberikan beban tarik yang mengacu pada ASTM D3689-07 prosedur E (Constant Rate of Uplift Test). Mobilisasi tahanan gesek tiang pada perpindahan tiang kritis menetukan tahanan gesek satuan ultimit. Hasil uji memperlihatkan bahwa semakin besar diameter tiang, tahanan gesek satuan ultimit tiang akan bertambah. Peningkatan tahanan gesek satuan ultimit tiang menunjukkan rata-rata sekitar 17,1 %.Kata kunci : Pondasi Tiang, Diameter Tiang, Tahanan Gesek Tiang.

Finite Element Analysis of Tandem Rubber O-Ring Sealing Structure at the End of Shaft

2013 ◽  
Vol 774-776 ◽  
pp. 25-29
Author(s):  
Cong Fang Hu ◽  
Yuan Qiang Tan
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Compression Rate ◽  
Element Analysis ◽  
Uniform Compression ◽  
Friction Factors ◽  
Sealing Performance ◽  
Sealing Failure

Based on the tandem sealing structure at the end of the shaft,a finite element model of rubber O-rings has been established and the sealing performance of rubber O-ring has been analyzed. There is an un-uniform compression among these O-rings which lead to the sealing failure. Under different friction factors, several groups of the rubber O-rings have been analyzed, finding that the friction factor is the reason of un-uniform compression. The effect of different average compression rate has been investigated, which has been integrated in the sealing criteria for the tandem O-rings, providing a reference for the optimization of tandem sealing structure at the end of the shaft. According to the sealing criteria for a single O-ring, the sealing criteria for the tandem O-rings is built.

Performance of a Short Multi-Grooved Capillary Compensated Hydrostatic Journal Bearing

1968 ◽  
Vol 183 (16) ◽  
pp. 107-115
Author(s):  
J. K. Patrick ◽  
N. N. S. Chen
Keyword(s):  
Journal Bearing ◽  
Load Capacity ◽  
Flow Characteristics ◽  
Lubricating Oil ◽  
Load Carrying Capacity ◽  
Straight Line ◽  
Load Carrying ◽  
Capillary Type ◽  
First Time ◽  
Oil Film Pressure

This paper presents the results of an extensive experimental investigation into the performance of a short multi-grooved bearing subjected to a range of static and alternating loads. Lubricating oil was supplied, at pressures of up to 2000 lb/in2, to capillary type restrictors connected to 10 closed-end axial grooves in the bearing. The bearing had a length/diameter ratio of 1/3 and operated with a journal speed and load frequency of 327 c/min. Measured load capacity, stiffness, and flow characteristics indicate that bearings of this type have a significant load-carrying capacity at zero journal speed and that the load capacity is increased by journal rotation. A feature of the journal behaviour under alternating loads is the movement of the journal centre along a straight line coincident with the load plane. The extensive oil film pressure surveys indicate for the first time the pressure distribution within narrow hydrostatic bearings and provide a basis for a realistic theoretical analysis of this type of bearing.

Nonlinear Finite Element Analysis of Super-Long Pile and Soil Interaction in Soft Soil

2011 ◽  
Vol 201-203 ◽  
pp. 1601-1605 ◽  
Author(s):  
Shang Ping Chen ◽  
Wen Juan Yao ◽  
Sheng Qing Zhu
Keyword(s):  
Finite Element ◽  
Constitutive Model ◽  
Soft Soil ◽  
Three Dimensional ◽  
Nonlinear Behavior ◽  
Element Model ◽  
Element Analysis ◽  
Friction Resistance ◽  
Tip Resistance ◽  
Side Friction

In this paper, a nonlinear three-dimensional finite element model for super-long pile and soil interaction is established. In this model, contact elements are applied to simulate the nonlinear behavior of interaction of super-long pile and soil. A nonlinear elastic constitutive model for concrete is employed to analyze stress-strain relation of pile shaft under the axial load and the Duncan-Chang’s nonlinear constitutive model is used to reflect nonlinear and inelastic properties of soil. The side friction resistance, axial force, pile-tip resistance, and developing trend of soil plastic deformation are obtained and compared with measured results from static load tests. It is demonstrated that a super-long pile has the properties of degradation of side friction resistance and asynchronous action between side and pile-tip resistance, which is different from piles with a short to medium length.

A Modified Chezy Formula for One-Dimensional Unsteady Frictional Resistance in Open Channel Flow

2021 ◽  
Vol 143 (5) ◽  
Author(s):  
Junwei Zhou ◽  
Weimin Bao ◽  
Geoffrey R. Tick ◽  
Hamed Moftakhari ◽  
Yu Li ◽  
...  
Keyword(s):  
Unsteady Flow ◽  
Frictional Resistance ◽  
Mitigation Strategies ◽  
Flood Routing ◽  
Flood Events ◽  
Complex Flow ◽  
Cross Sectional ◽  
Friction Resistance ◽  
Flow Unsteadiness ◽  
Better Than

Abstract It has been observed in literature that for unsteady flow conditions the one-to-one relationships between flow depth, cross-sectional averaged velocity, and frictional resistance as determined from steady uniform flow cases may not be appropriate for these more complex flow systems. Thus, a general friction resistance formula needs to be modified through the addition of new descriptive terms to account for flow unsteadiness, in order to eliminate errors due to uniform and steady-flow assumptions. An extended Chezy formula incorporating both time and space partial derivatives of hydraulic parameters was developed using dimensional analysis to investigate the relationship between flow unsteadiness and friction resistance. Results show that the proposed formula performs better than the traditional Chezy formula for simulating real hydrograph cases whereby both formula coefficients are individually identified for each flood event and coefficients are predetermined using other flood events as calibration cases. Although the extended Chezy formula as well as the original Chezy formula perform worse with the increasing degree of flow unsteadiness, its results are less dramatically affected by unsteadiness intensity, thereby improving estimations of flood routing. As a result, it tends to perform much better than traditional Chezy formula for severe flood events. Under more complex conditions whereby peak flooding events may occur predominantly under unsteady flow, the extended Chezy model may provide as a valuable tool for researchers, practitioners, and water managers for assessing and predicting impacts for flooding and for the development of more appropriate mitigation strategies and more accurate risk assessments.

Thermal analysis of the triple-phase asynchronous motor-reducer coupling system by thermal network method

2020 ◽  
Vol 234 (12) ◽  
pp. 2851-2861
Author(s):  
Mingzhang Chen ◽  
Wuhao Zhuang ◽  
Song Deng ◽  
Chengjie Zhu
Keyword(s):  
Asynchronous Motor ◽  
Experimental Result ◽  
Lubricating Oil ◽  
Power Coefficient ◽  
Element Analysis ◽  
Thermal Network ◽  
Coupling System ◽  
Network Method ◽  
Core Components ◽  
Thermal Network Method

As the core components of mechanical power system, triple-phase asynchronous motor and reducer are required strictly for temperature control. In this paper, the triple-phase asynchronous motor and the reducer are regarded as a coupling system, and thermal network method is used to predict the temperature field distribution of the coupling system. The predicted temperature of the thermal network method is consistent with the experimental result and the finite-element analysis. Furthermore, analysis shows that motor output power, coefficient of friction between teeth and lubricating oil parameters have a great effect on reducing the temperature of the coupling system.

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