Effect of Flow Characteristics on the Operation of a Solenoid Switching Control Valve

2015 ◽  
Vol 799-800 ◽  
pp. 1113-1116
Author(s):  
Cheol Heui Han ◽  
Sang Jin Ma ◽  
Myung Jin Chung
Keyword(s):  
Numerical Simulation ◽  
Compressible Flow ◽  
High Speed ◽  
Stokes Equations ◽  
Flow Characteristics ◽  
Control Valve ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Flow Acceleration ◽  
Choked Flow

Effect of the compressible flow characteristics inside a high-speed electromagnetic valve on the operation of the valve is investigated using a numerical simulation. The numerical simulation solves Navier-Stokes equations and heat transfer equations by coupling, and the compressible flow phenomena inside the valves are studied focusing on the shock structures. . Fluid-structure interaction is considered using freely moving grid deformations. The flow patterns of subsonic acceleration, choked flow, supersonic expansion, and a strong curved shock were observed inside the valve during on/off operations. The subsonic flow acceleration affected the operation characteristics of the valve.

Numerical simulation of the stalled flow within a vaned centrifugal pump

2004 ◽  
Vol 218 (4) ◽  
pp. 425-435 ◽  
Author(s):  
K M Guleren ◽  
A Pinarbasi
Keyword(s):  
Numerical Simulation ◽  
Centrifugal Pump ◽  
High Speed ◽  
Stokes Equations ◽  
Reverse Flow ◽  
Flow Characteristics ◽  
Navier Stokes ◽  
Leakage Flow ◽  
Navier Stokes Equations ◽  
Low Pass

The main goal of the present work is to analyse the numerical simulation of a centrifugal pump by solving Navier-Stokes equations, coupled with the ‘standard k-∊’ turbulence model. The pump consists of an impeller having five curved blades with nine diffuser vanes. The shaft rotates at 890r/min. Flow characteristics are assumed to be stalled in the appropriate region of flowrate levels of 1.31-2.861/s. Numerical analysis techniques are performed on a commercial FLUENT package program assuming steady, incompressible flow conditions with decreasing flowrate. Under stall conditions the flow in the diffuser passage alternates between outward jetting when the low-pass-filtered pressure is high to a reverse flow when the filtered pressure is low. Being below design conditions, there is a consistent high-speed leakage flow in the gap between the impeller and the diffuser from the exit side of the diffuser to the beginning of the volute. Separation of this leakage flow from the diffuser vane causes the onset of stall. As the flowrate decreases both the magnitude of the leakage within the vaneless part of the pump and reverse flow within a stalled diffuser passage increase. As this occurs, the stall-cell size extends from one to two diffuser passages. Comparisons are made with experimental data and show good agreement.

scholarly journals Kinematic, Dynamic, and Energy Characteristics of Diastolic Flow in the Left Ventricle

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Seyed Saeid Khalafvand ◽  
Tin-Kan Hung ◽  
Eddie Yin-Kwee Ng ◽  
Liang Zhong
Keyword(s):  
Mitral Valve ◽  
Left Ventricle ◽  
Stokes Equations ◽  
Flow Characteristics ◽  
Temporal Variations ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Energy Characteristics ◽  
Flow Acceleration ◽  
Acceleration And Deceleration

Blood flow characteristics in the normal left ventricle are studied by using the magnetic resonance imaging, the Navier-Stokes equations, and the work-energy equation. Vortices produced during the mitral valve opening and closing are modeled in a two-dimensional analysis and correlated with temporal variations of the Reynolds number and pressure drop. Low shear stress and net pressures on the mitral valve are obtained for flow acceleration and deceleration. Bernoulli energy flux delivered to blood from ventricular dilation is practically balanced by the energy influx and the rate change of kinetic energy in the ventricle. The rates of work done by shear and energy dissipation are small. The dynamic and energy characteristics of the 2D results are comparable to those of a 3D model.

scholarly journals Finite-scale equations for compressible fluid flow

2009 ◽  
Vol 367 (1899) ◽  
pp. 2861-2871 ◽  
Author(s):  
L.G. Margolin
Keyword(s):  
Numerical Simulation ◽  
Turbulent Flows ◽  
Compressible Fluid ◽  
High Speed ◽  
Energy Transport ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
One Dimensional ◽  
Scale Models

Finite-scale equations (FSE) describe the evolution of finite volumes of fluid over time. We discuss the FSE for a one-dimensional compressible fluid, whose every point is governed by the Navier–Stokes equations. The FSE contain new momentum and internal energy transport terms. These are similar to terms added in numerical simulation for high-speed flows (e.g. artificial viscosity) and for turbulent flows (e.g. subgrid scale models). These similarities suggest that the FSE may provide new insight as a basis for computational fluid dynamics. Our analysis of the FS continuity equation leads to a physical interpretation of the new transport terms, and indicates the need to carefully distinguish between volume-averaged and mass-averaged velocities in numerical simulation. We make preliminary connections to the other recent work reformulating Navier–Stokes equations.

scholarly journals NUMERICAL SIMULATION OF SUBSONIC FLOW OVER A PROFILE

2018 ◽  
Vol 26 (4) ◽  
pp. 10-15
Author(s):  
S. V. Alekseyenko
Keyword(s):  
Numerical Simulation ◽  
Reynolds Number ◽  
Mach Number ◽  
Compressible Flow ◽  
Subsonic Flow ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Number Variation ◽  
Viscous Compressible Flow

A methodology and software-methodical support for describing the processes of flow around a wing profile by a viscous compressible flow based on the Reynolds-averaged Navier – Stokes equations using the Spalart – Almaras turbulence model is developed. The effect of Mach number variation at constant Reynolds number on the profile performance coefficients is analyzed.

scholarly journals Vibrations of Nonlinear Elastic Structure Excited by Compressible Flow

2021 ◽  
Vol 11 (11) ◽  
pp. 4748
Author(s):  
Monika Balázsová ◽  
Miloslav Feistauer ◽  
Jaromír Horáček ◽  
Adam Kosík
Keyword(s):  
Compressible Flow ◽  
Nonlinear Elasticity ◽  
Vocal Tract ◽  
Stokes Equations ◽  
Vocal Folds ◽  
Nonlinear Material ◽  
Navier Stokes ◽  
Arbitrary Lagrangian Eulerian ◽  
Navier Stokes Equations ◽  
Reliable Solution

This study deals with the development of an accurate, efficient and robust method for the numerical solution of the interaction of compressible flow and nonlinear dynamic elasticity. This problem requires the reliable solution of flow in time-dependent domains and the solution of deformations of elastic bodies formed by several materials with complicated geometry depending on time. In this paper, the fluid–structure interaction (FSI) problem is solved numerically by the space-time discontinuous Galerkin method (STDGM). In the case of compressible flow, we use the compressible Navier–Stokes equations formulated by the arbitrary Lagrangian–Eulerian (ALE) method. The elasticity problem uses the non-stationary formulation of the dynamic system using the St. Venant–Kirchhoff and neo-Hookean models. The STDGM for the nonlinear elasticity is tested on the Hron–Turek benchmark. The main novelty of the study is the numerical simulation of the nonlinear vocal fold vibrations excited by the compressible airflow coming from the trachea to the simplified model of the vocal tract. The computations show that the nonlinear elasticity model of the vocal folds is needed in order to obtain substantially higher accuracy of the computed vocal folds deformation than for the linear elasticity model. Moreover, the numerical simulations showed that the differences between the two considered nonlinear material models are very small.

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