A computational study on the flow characteristics of a self-compensating liquid balancer

2011 ◽  
Vol 25 (6) ◽  
pp. 1465-1474 ◽  
Author(s):  
Chung-Hyo Jung ◽  
Jin-Tak Kim ◽  
Yun-Ho Choi
Keyword(s):  
Computational Study ◽  
Flow Characteristics

scholarly journals Adverse Hemodynamic Conditions Associated with Mechanical Heart Valve Leaflet Immobility

2018 ◽  
Vol 5 (3) ◽  
pp. 74 ◽  
Author(s):  
Fardin Khalili ◽  
Peshala Gamage ◽  
Richard Sandler ◽  
Hansen Mansy
Keyword(s):  
Heart Valve ◽  
Heart Valves ◽  
Computational Study ◽  
Cell Damage ◽  
Mechanical Heart Valve ◽  
Flow Characteristics ◽  
Maximal Velocity ◽  
Valve Dysfunction ◽  
Promising Tool ◽  
Artificial Heart Valves

Artificial heart valves may dysfunction, leading to thrombus and/or pannus formations. Computational fluid dynamics is a promising tool for improved understanding of heart valve hemodynamics that quantify detailed flow velocities and turbulent stresses to complement Doppler measurements. This combined information can assist in choosing optimal prosthesis for individual patients, aiding in the development of improved valve designs, and illuminating subtle changes to help guide more timely early intervention of valve dysfunction. In this computational study, flow characteristics around a bileaflet mechanical heart valve were investigated. The study focused on the hemodynamic effects of leaflet immobility, specifically, where one leaflet does not fully open. Results showed that leaflet immobility increased the principal turbulent stresses (up to 400%), and increased forces and moments on both leaflets (up to 600% and 4000%, respectively). These unfavorable conditions elevate the risk of blood cell damage and platelet activation, which are known to cascade to more severe leaflet dysfunction. Leaflet immobility appeared to cause maximal velocity within the lateral orifices. This points to the possible importance of measuring maximal velocity at the lateral orifices by Doppler ultrasound (in addition to the central orifice, which is current practice) to determine accurate pressure gradients as markers of valve dysfunction.

scholarly journals Computational study on the aerodynamics of a long-shrouded contra-rotating rotor in hover

2019 ◽  
Vol 11 ◽  
pp. 175682931983368
Author(s):  
Chao Huo ◽  
Peng Lv ◽  
Anbang Sun
Keyword(s):  
Flow Field ◽  
Opposite Direction ◽  
Computational Study ◽  
Flow Characteristics ◽  
The Other ◽  
Complex Flow ◽  
Sliding Mesh ◽  
Global Performance ◽  
Mesh Method ◽  
Downstream Flow

This paper aims to investigate the aerodynamics including the global performance and flow characteristics of a long-shrouded contra-rotating rotor by developing a full 3D RANS computation. Through validations by current experiments on the same shrouded contra-rotating rotor, the computation using sliding mesh method and the computational zone with an extended nozzle downstream flow field effectively works; the time-averaged solution of the unsteady computation reveals that more uniform flow presents after the downstream rotor, which implies that the rear rotor rotating at opposite direction greatly compensates and reduces the wake; the unsteady computations further explore the flow field throughout the whole system, along the span and around blade tips. Complex flow patterns including the vortices and their interactions are indicated around the blade roots and tips. For further identifying rotor configurations, the rotor–rotor distance and switching two rotor speeds were studied. The computation reveals that setting the second rotor backwards decreases the wake scale but increases its intensity in the downstream nozzle zone. However, for the effect of switching speeds, computations cannot precisely solve the flow when the rear rotor under the windmill because of the upstream rotor rotating much faster than the other one. All the phenomena from computations well implement the experimental observations.

A Computational Study on the Effect of Angles of Attack on a Double-Cone Type Supersonic Inlet With Bleeding System

2010 ◽  
Author(s):  
Kyung Jin Ryu ◽  
Seol Lim ◽  
Sang Dug Kim ◽  
Dong Joo Song
Keyword(s):  
Boundary Layer ◽  
Flow Field ◽  
Computational Study ◽  
Angle Of Attack ◽  
Flow Characteristics ◽  
Uniform Flow ◽  
Double Cone ◽  
Interface Plane ◽  
Supersonic Inlet ◽  
Cone Type

The flow characteristics on a supersonic inlet with bleeding system at various angles of attack are studied by using computational 3D turbulent flow analysis. A turbulent CSCM compressible upwind flux difference splitting Navier-Stokes method with k-w turbulence model is used to compute the inlet flowfields. MPICH-2.0 library and PC-cluster system are used to reduce computational times. Distortion and average of total pressure recovery at the AIP (aerodynamic interface plane) are used as evaluation criteria of inlet performance. The flow characteristics at zero of angle of attack of double-cone type supersonic inlet without and with bleeding system have been compared. Without bleeding system inlet with the strong SBLI (shock/boundary-layer interaction) induces slow flow recovery near the throat and produces very thick boundary layer downstream. But the bleeding system successfully removes the low energy flow from the boundary layer near the throat. As the angle of attack at the AIP because large, we can see more non-uniform flow field, and the non-uniform flow field is the major aggravating factor of inlet performance.

Investigation on Flow Characteristics and Performance of a Vertical Axis Wind Turbine With Deflector Plates

2019 ◽  
Author(s):  
K. Karthik Selva Kumar ◽  
Vinayak Kulkarni ◽  
Niranjan Sahoo
Keyword(s):  
Wind Turbine ◽  
Computational Study ◽  
Flow Characteristics ◽  
Vertical Axis ◽  
Vertical Axis Wind Turbine ◽  
Near Wake ◽  
Flow Phenomenon ◽  
Sliding Mesh ◽  
And Performance ◽  
Accelerated Flow

Abstract In this article, a 3D computational study has been performed to understand the flow phenomenon over the vertical axis wind turbine with a three-bladed NACA0021. The rotary motion of the VAWT simulated with sliding mesh techniques with reference to the SST-Kω turbulence model using the CFD software. The observed results were found to be having a significant improvement in the enhancement of the power output. Also, the investigation was move forwarded to understand the flow characteristics of the VAWT with the presence of deflector plates in different orientation at the upstream conditions. The present of deflector plates creates an augmented flow phenomenon which creates an accelerated flow at the near wake region, causing a significant improvement in the coefficient of power of the wind turbine.

Multiphase Flow Investigation of a Centrifugal Filter Using Computational Fluid Dynamics and Experiments

2002 ◽  
Author(s):  
Steven D. Megson ◽  
Michael Wilson ◽  
Stuart A. MacGregor
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Computational Study ◽  
Flow Characteristics ◽  
High Tech ◽  
Outlet Channel ◽  
Two Phase ◽  
Base Oil ◽  
Factors Affecting ◽  
Cfd Models

Modern “high tech” lubricant oils have been developed to contain a high level of dispersant additive to the base oil. As contaminant loading has increased, designers are required to address the problem of controlling the contamination found in the oil. One method is the use of bypass centrifugal sedimentation. This paper describes a computational study of the basic flow characteristics in a centrifugal sedimenting rotor using the computational fluid dynamics (CFD) package STAR-CD. Simplified CFD models have indicated regions of flow which would be difficult to demonstrate by experimental methods alone. For example, backflow from the outlet channel is found to cause a disruptive secondary flow in some models, but this flow is contained by the inclusion of a more realistic geometry. Two–phase flow computations have also been carried out to investigate the behaviour of spherical particulates of different sizes. Flow and geometry factors affecting the centrifuge performance are discussed.

Experimental and Computational Study of Flow Characteristics in a Drilled Perforated Core

2012 ◽  
Author(s):  
Datong Sun ◽  
Rajani Satti ◽  
Darren Ochsner ◽  
Tim Sampson ◽  
Baoyan Li ◽  
...  
Keyword(s):  
Computational Study ◽  
Flow Characteristics

Effect of Pitch Chord Ratio and Side Wall Expansion Angle on Flow Through Vane Swirlers

2006 ◽  
Author(s):  
R. Thundil Karuppa Raj ◽  
V. Ganesan
Keyword(s):  
Computational Study ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Side Wall ◽  
Reynolds Stress Model ◽  
Swirl Flow ◽  
Expansion Angle ◽  
Turbulence Effects ◽  
Flow Field Characteristics ◽  
Flow Through

This paper is concerned with the computational study of steady flow through the vane swirlers. Swirl flow field characteristics for various pitch chord ratio (s/c) at swirler mean radius are studied for a 45° vane swirler under both sudden and gradual expansions with side-wall expansion angles of 90° and 45° respectively. In the computational study the geometry and meshing is done using pre-processor GAMBIT. Three-dimensional flow within the geometry and through the swirler has been simulated by solving the appropriate governing equations viz. conservation of mass and momentum using FLUENT code. Turbulence effects are taken care of by the Reynolds stress model and shear stress transport k-ω model for high swirls and standard k-ε model for low and medium swirls. The effect of pitch to chord ratio (s/c) on flow characteristics have been studied. The predicted results are validated with the experimental data available in the literature for s/c ratio of 1. The numerical results of axial velocity profiles downstream of the swirler at various axial planes are found to be in close agreement with the experimental results. It is found that the s/c ratio of 1 provides good turning efficiency.

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