The Lubrication characteristics of the vane tip under pressure boundary condition of oil hydraulic vane pump

2006 ◽  
Vol 20 (10) ◽  
pp. 1716-1721 ◽  
Author(s):  
Ihn-Sung Cho ◽  
Seok-Hyung Oh ◽  
Kyu-Keun Song ◽  
Jae-Youn Jung
Keyword(s):  
Boundary Condition ◽  
Vane Pump ◽  
Pressure Boundary Condition ◽  
Lubrication Characteristics ◽  
Vane Tip

scholarly journals A Solution to Pressure Equation with Its Boundary Condition of Combining Tangential and Normal Pressure Relations

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1507
Author(s):  
Hui Xiao ◽  
Wei Liu
Keyword(s):  
Boundary Condition ◽  
Numerical Algorithm ◽  
Iteration Process ◽  
Normal Pressure ◽  
Constitutive Law ◽  
Navier Stokes ◽  
Numerical Verification ◽  
Pressure Equation ◽  
Navier Stokes Equation ◽  
Pressure Boundary Condition

Pressure is a physical quantity that is indispensable in the study of transport phenomena. Previous studies put forward a pressure constitutive law and constructed a partial differential equation on pressure to study the convection with or without heat and mass transfer. In this paper, a numerical algorithm was proposed to solve this pressure equation by coupling with the Navier-Stokes equation. To match the pressure equation, a method of dealing with pressure boundary condition was presented by combining the tangential and normal direction pressure relations, which should be updated dynamically in the iteration process. Then, a solution to this pressure equation was obtained to bridge the gap between the mathematical model and a practical numerical algorithm. Through numerical verification in a circular tube, it is found that the proposed boundary conditions are applicable. The results demonstrate that the present pressure equation well describes the transport characteristics of the fluid.

scholarly journals A variational principle for fluid sloshing with vorticity, dynamically coupled to vessel motion

2019 ◽  
Vol 475 (2224) ◽  
pp. 20180642 ◽  
Author(s):  
H. Alemi Ardakani ◽  
T. J. Bridges ◽  
F. Gay-Balmaz ◽  
Y. H. Huang ◽  
C. Tronci
Keyword(s):  
Boundary Condition ◽  
Free Surface ◽  
Variational Principle ◽  
Stream Function ◽  
Fluid Motion ◽  
Two Dimensional ◽  
Euclidean Group ◽  
Fluid Sloshing ◽  
Pressure Boundary Condition ◽  
Vessel Motion

A variational principle is derived for two-dimensional incompressible rotational fluid flow with a free surface in a moving vessel when both the vessel and fluid motion are to be determined. The fluid is represented by a stream function and the vessel motion is represented by a path in the planar Euclidean group. Novelties in the formulation include how the pressure boundary condition is treated, the introduction of a stream function into the Euler–Poincaré variations, the derivation of free surface variations and how the equations for the vessel path in the Euclidean group, coupled to the fluid motion, are generated automatically.

Vane tip detachment in a positive displacement vane pump

1998 ◽  
Vol 12 (5) ◽  
pp. 881-887 ◽  
Author(s):  
Myung-Rae Cho ◽  
Dong-Chul Han
Keyword(s):  
Vane Pump ◽  
Positive Displacement ◽  
Vane Tip

Unsteady Simulation and Analysis on Centrifugal Impeller With Self-Adaptive Casing Treatment

2013 ◽  
Author(s):  
Tong Wang ◽  
Wei Wang ◽  
Chuangang Gu
Keyword(s):  
Boundary Condition ◽  
Back Pressure ◽  
The Self ◽  
Centrifugal Impeller ◽  
Bypass Flow ◽  
Unstable Flow ◽  
Recirculation Flow ◽  
Casing Treatment ◽  
Pressure Boundary Condition ◽  
Self Adaptive

A self-adaptive casing treatment for unshrouded centrifugal compressor was proposed in our previous studies. It is a kind of passive control techniques. The experimental results proved that the stable working range of the compressor was extended greatly with the technique. As for the stability mechanism, there is no convinced explanation. Many researchers believe that the unsteady flow could be one of the key points. In the paper, steady and unsteady numerical simulations were carried out to get the performances of the centrifugal impeller by ANSYS CFX software. The numerical method was validated by comparing with the experimental results. It was found that there were two types of flow pattern in the bleeding-recirculation passages by the numerical simulation with the self-adaptive casing treatment. One was the recirculation flow at the smaller flowrate working conditions and the other was bypass flow at the larger flowrate working conditions. The pressure at the bleeding ports was more than that at the recirculation port at the smaller flowrate. It would result in the recirculation flow in the bleeding-recirculation passages. Otherwise, it would result in the bypass flow in the bleeding-recirculation passages. The numerical results of each bleeding-recirculation passage provided the variation of mass flowrate in it with the pressure difference. The relation of the pressure drop coefficient and Reynolds number based on the bleeding hole was fitted. It was different for the recirculation flow and bypass flow. It is helpful to decide the position of the bleeding ports during the centrifugal compressor design process. Moreover, an unsteady numerical simulation method with the increasing back pressure boundary condition was proposed to investigate the unsteady process approaching to the numerical stall point or unstable flow. The dynamic pressure data in impeller and diffuser were recorded. The amplitudes of the data were picked up to compare the time dependent process. The dynamic pressure at the inlet of diffuser fluctuated more strongly than those at the other positions while the back pressure was increased to the numerical stall point. The experimental data provided the similar phenomena. It suggested that the unstable flow tendency could be caught up by the unsteady simulation process with the increasing back pressure boundary condition. Furthermore, the time dependent flow fields at the blade tip region were compared on the conditions with and without the self-adaptive casing treatment. The effect of the self-adaptive casing treatment was proved by unsteady numerical method with the increasing back pressure boundary condition. The stability mechanism of the self-adaptive casing treatment was explained to some extent.

Numerical simulation of intake and compression flow in a four-valve pent-roof spark ignition engine and validation with LDV data

2000 ◽  
Vol 214 (4) ◽  
pp. 361-372 ◽  
Author(s):  
W. T. Kim ◽  
K. Y. Huth ◽  
J. W. Lee ◽  
K. Y. Kang
Keyword(s):  
Boundary Condition ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Treatment Technique ◽  
Mean Velocity ◽  
Fluctuation Velocity ◽  
Pressure Boundary Condition ◽  
Intake Flow ◽  
Inlet Boundary Condition ◽  
Good Agreement

The intake and compression flows in a motoring four-valve pent-roof spark ignition engine are calculated and compared with the laser Doppler velocimetry (LDV) data. A simple valve treatment technique is used to avoid excessive difficulty in generation of a body-fitted grid for multiple moving valves. A constant-pressure boundary condition is applied at the intake port inlet. Results show good agreement for the fluctuation velocity, while there is some discrepancy in the mean velocity owing to uncertainty in the inlet boundary condition. The tumble ratio and the average fluctuation velocity remain approximately constant or rise slightly owing to the spin-up phenomenon near top dead centre (TDC) after rapid decay of the strong intake flow and turbulence in the compression stroke.

scholarly journals Analysis of lubrication characteristics in oil hydraulic vane tip contacts.

1990 ◽  
Vol 56 (523) ◽  
pp. 776-782 ◽  
Author(s):  
Tsunamitsu NAKAHARA ◽  
Keiji KYOGOKU ◽  
Jae-Youn JUNG
Keyword(s):  
Lubrication Characteristics ◽  
Vane Tip
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