scholarly journals Hydrodynamic processes in the piston and cylinder unit of axial-piston hydraulic machines

2017 ◽  
pp. 86-90
Author(s):  
A. O. Kuz'min ◽  
V. V. Popov ◽  
S. M. Stazhkov
Keyword(s):  
Reynolds Equation ◽  
Pressure Field ◽  
Fluid Layer ◽  
Working Fluid ◽  
Sweep Method ◽  
Pressure Fields ◽  
Hydraulic Machines ◽  
Piston Mechanism ◽  
Hydrodynamic Processes ◽  
Axial Piston

The purpose of the research was to analyze the kinematics of the piston mechanism of an axial-piston hydraulic machine with an adjustable-angle cam plate. The kinematic analysis resulted in establishing various types of relative motion of the piston in the guide bushing, writing and solving Reynolds equation with respect to velocities. A sweep method was used to construct a pressure field in the working fluid layer between the piston and the guide bushing. Pressure fields are constructed for several cases of kinematics of the piston mechanism.

Experiments on Laminar Flow Development in Rectangular Ducts

1967 ◽  
Vol 89 (1) ◽  
pp. 116-123 ◽  
Author(s):  
E. M. Sparrow ◽  
C. W. Hixon ◽  
G. Shavit
Keyword(s):  
Velocity Field ◽  
Pressure Drop ◽  
Cross Sections ◽  
Pressure Field ◽  
Working Fluid ◽  
Aspect Ratios ◽  
Pressure Fields ◽  
Flow Development ◽  
Pressure Development ◽  
Axial Development

The development of the laminar velocity and pressure fields in the hydrodynamic entrance region of rectangular ducts has been explored experimentally. Duct cross sections having aspect ratios of 5:1 and 2:1 were employed in the investigation; air was the working fluid. It was found that the development of the pressure field is much more rapid than that of the velocity field. The entrance length, relative to pressure development, is representable as (z/De)/Re = 0.02 for both ducts. The incremental pressure drop due to the development of the flow was deduced from the experimental data as being approximately equal to one velocity head. The axial development of the velocity field is illustrated by a sequence of velocity profiles measured along the symmetry lines of the cross section. The flow development in the 5:1 duct is found to be somewhat more rapid than in the 2:1 duct. Comparisons of the experimental results are made with available predictions of analysis, all of which are based on approximate models of the flow field. In general, the analyses over predict the incremental pressure drop due to flow development. The development of the velocity field appears to be reasonably well described by analysis.

scholarly journals Results of identification and optimization of the parameters of axial piston pump

2021 ◽  
Author(s):  
Radovan Petrović ◽  
Nenad Todić ◽  
Slobodan Savić ◽  
Maja Andjelković
Keyword(s):  
High Resolution ◽  
Input Data ◽  
Simultaneous Presentation ◽  
Axial Piston Pump ◽  
Optimization Of Parameters ◽  
Axial Piston Pumps ◽  
Hydrodynamic Processes ◽  
3D Software ◽  
2D And 3D ◽  
Axial Piston

In the development of applicative software for mathematical modelling, identification, and optimization of parameters of axial piston pumps, special attention is paid to the real need of the engineers' practice. We used the original graphical 2D and 3D software for the application in real-time with a simultaneous presentation and processing in 24 windows of high resolution. Here it is mentioned that during optimization and identification of axial piston pump's parameters, we automatically form and present several hundreds of the complex 2D diagrams, which enables to intervene at any point in the study of hydrodynamic processes by the change of input data, where the following flow of identification and optimization is changed.

scholarly journals Designing a top cooling system for an electromagnetic calorimeter

2021 ◽  
Vol 345 ◽  
pp. 00015
Author(s):  
Matěj Jeřábek ◽  
Michal Volf ◽  
Daniel Duda
Keyword(s):  
Numerical Simulation ◽  
Pressure Field ◽  
Cooling System ◽  
Flow Simulation ◽  
Electromagnetic Calorimeter ◽  
3D Flow ◽  
Commercial Software ◽  
Pressure Fields ◽  
Detailed Evaluation ◽  
Temperature And Pressure

The article describes a numerical simulation of flow in the cooling system of an electromagnetic calorimeter by analysing the temperature and pressure fields. Two fundamentally different approaches were used to analyse the pressure field - analytical 1D calculation and numerical 3D flow simulation. The article contains a detailed evaluation and description of individual analyses using the commercial software ANSYS 2020 R1.

Vortex street impinging upon an elliptical leading edge

1990 ◽  
Vol 211 ◽  
pp. 211-242 ◽  
Author(s):  
Ismet Gursul ◽  
Donald Rockwell
Keyword(s):  
Velocity Field ◽  
Flow Visualization ◽  
Pressure Field ◽  
Leading Edge ◽  
Vortex Street ◽  
Transverse Displacement ◽  
Vorticity Field ◽  
Measured Velocity ◽  
Vortical Structures ◽  
Pressure Fields

The interaction of a Kármán vortex street with an elliptical edge is investigated experimentally. Basic types of interaction, as a function of scale and transverse displacement of the incident vortex street, are revealed using flow visualization. Unsteady pressure fields induced by these interactions are measured by a phase-averaging technique and correlated with the visualized flow patterns for basic classes of interactions.For a generic vortex–edge interaction, measurements of the phase-averaged velocity field allow construction of streamlines and vorticity contours showing the details of the interaction, including distortion of the vortical structures near the edge. The pressure field is calculated from the measured velocity field and interpreted in relation to the vortical structures.Simulation of flow visualization using the measured velocity field demonstrates possible misinterpretations related to the underlying vorticity field.

scholarly journals Flow regimes in a multi-gap circular Couette-Taylor system with opposite rotating cylinders

2021 ◽  
Vol 2119 (1) ◽  
pp. 012103
Author(s):  
A F Serov ◽  
V N Mamonov ◽  
A D Nazarov ◽  
N B Miskiv
Keyword(s):  
Flow Structure ◽  
Low Frequency ◽  
Working Fluid ◽  
Frequency Spectra ◽  
Initial Information ◽  
Heat Generator ◽  
Working Space ◽  
Resistance Torque ◽  
Hydrodynamic Processes ◽  
Circular Space

Abstract This work investigates the flow structure in the gaps of a multi-cylinder circular Couette-Taylor system, which is a model of a two-rotor heat generator. The initial information for studying the flow structure was data on the magnitude of the resistance torque to rotors opposed rotation, as well as on the nature of the amplitude-frequency spectrum of pulsations of this torque, depending on the viscosity of the working fluid and the rotational speed of the heat generator rotors. The obtained data allow comparing the nature of hydrodynamic processes in the single and obtained multi-gap circular space of Couette-Taylor and calculating the parameters of structural formations in the multi-gap working space of the heat generator. At relative rotational speeds of rotors (3-50) rad/s, the main energy of flow pulsations (up to 90%) is found in the amplitude-frequency spectra in the frequency range (12-70) Hz. It is associated with vortices first described by Taylor, which are extended low-frequency regularly alternating spirals and vortex structures with right and left rotation in the region of higher frequencies (200– 500) Hz; their frequency is determined by the width of the annular gaps of the multi-cylinder system.

Effect of piston clearance on the lubrication performance in axial piston pump

2019 ◽  
Vol 72 (1) ◽  
pp. 146-150
Author(s):  
Bora Lee ◽  
Yonghun Yu ◽  
Yong-Joo Cho
Keyword(s):  
Reynolds Equation ◽  
Design Method ◽  
Contact Region ◽  
Content Type ◽  
Piston Cylinder ◽  
Leakage Flow Rate ◽  
Lubrication Performance ◽  
Secondary Motion ◽  
Lubrication Characteristics ◽  
Axial Piston

Purpose This paper aims to provide a reliable and efficient numerical piston–cylinder design method and assess the effect of clearance on the piston-cylinder lubrication. Design/methodology/approach Numerical analyses of lubrication characteristics were performed for the piston–cylinder interface. The axial piston was numerically modeled, and the film pressure was calculated using the unsteady two-dimensional Reynolds equation. The behavior of the piston was analyzed by calculating the eccentricity satisfying the force and moment balance. Findings The secondary motion of the piston included numerically simulated several cycles until the piston behavior converged, and contact with the inner wall of the cylinder and friction region was estimated. Results showed that the piston–cylinder clearance affected the contact force, length of the contact region and leakage flow rate. Originality/value This result improves the understanding of the piston–cylinder lubrication and suggests considerations in terms of lubrication in clearance design.

scholarly journals Computation of Pressure Fields around a Two-Dimensional Circular Cylinder Using the Vortex-In-Cell and Penalization Methods

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Seung-Jae Lee ◽  
Jun-Hyeok Lee ◽  
Jung-Chun Suh
Keyword(s):  
Circular Cylinder ◽  
Solid Body ◽  
Pressure Field ◽  
Stokes Equations ◽  
Computational Cost ◽  
Fixed Time ◽  
Computational Grids ◽  
Penalty Term ◽  
Pressure Fields ◽  
Wide Range

The vorticity-velocity formulation of the Navier-Stokes equations allows purely kinematical problems to be decoupled from the pressure term, since the pressure is eliminated by applying the curl operator. The Vortex-In-Cell (VIC) method, which is based on the vorticity-velocity formulation, offers particle-mesh algorithms to numerically simulate flows past a solid body. The penalization method is used to enforce boundary conditions at a body surface with a decoupling between body boundaries and computational grids. Its main advantage is a highly efficient implementation for solid boundaries of arbitrary complexity on Cartesian grids. We present an efficient algorithm to numerically implement the vorticity-velocity-pressure formulation including a penalty term to simulate the pressure fields around a solid body. In vorticity-based methods, pressure field can be independently computed from the solution procedure for vorticity. This clearly simplifies the implementation and reduces the computational cost. Obtaining the pressure field at any fixed time represents the most challenging goal of this study. We validate the implementation by numerical simulations of an incompressible viscous flow around an impulsively started circular cylinder in a wide range of Reynolds numbers: Re=40, 550, 3000, and 9500.

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