Cavitation Avoidance in a Hydraulic Disk Valve

2017 ◽  
Author(s):  
Yoshiharu Inaguma
Keyword(s):  
Disk Valve

scholarly journals Numerical and experimental studies of gas–liquid flow and pressure drop in multiphase pump valves

2020 ◽  
Vol 103 (3) ◽  
pp. 003685042094088
Author(s):  
Yi Ma ◽  
Minjia Zhang ◽  
Huashuai Luo
Keyword(s):  
Pressure Drop ◽  
Two Phase Flow ◽  
Volume Fraction ◽  
Test System ◽  
Ball Valve ◽  
Phase Flow ◽  
Two Phase ◽  
Pressure Drops ◽  
Disk Valve ◽  
Predicted Values

A numerical and experimental study was carried out to investigate the two-phase flow fields of the typical three valves used in the multiphase pumps. Under the gas volume fraction conditions in the range of 0%–100%, the three-dimensional steady and dynamic two-phase flow characteristics, pressure drops, and their multipliers of the ball valve, cone valve, and disk valve were studied, respectively, using Eulerian–Eulerian approach and dynamic grid technique in ANSYS FLUENT. In addition, a valve test system was built to verify the simulated results by the particle image velocimetry and pressure test. The flow coefficient CQ (about 0.989) of the disk valve is greater than those of the other valves (about 0.864) under the steady flow with a high Reynolds number. The two-phase pressure drops of the three valves fluctuate in different forms with the vibration of the cores during the dynamic opening. The two-phase multipliers of the fully opened ball valve are consistent with the predicted values of the Morris model, while those of the cone valve and disk valve had the smallest differences with the predicted values of the Chisholm model. Through the comprehensive analysis of the flow performance, pressure drop, and dynamic stability of the three pump valves, the disk valve is found to be more suitable for the multiphase pumps due to its smaller axial space, resistance loss, and better flow capacity.

Planiks disk valve prostheses

1996 ◽  
Vol 69 (3) ◽  
pp. 382-389
Author(s):  
Yu. P. Ostrovskii
Keyword(s):  
Disk Valve ◽  
Valve Prostheses

Steady-State Theoretical Model of an Electro-Hydraulic Single-Disk Pilot Valve

1992 ◽  
Vol 114 (2) ◽  
pp. 293-298 ◽  
Author(s):  
Y. Sun ◽  
G. A. Parker
Keyword(s):  
Steady State ◽  
Theoretical Model ◽  
Experimental Verification ◽  
Control Device ◽  
Null Condition ◽  
Electromagnetic Model ◽  
Disk Valve ◽  
Single Disk ◽  
Electromagnetic Characteristics ◽  
Pilot Valve

The paper describes an electro-hydraulic single floating-disk valve suitable for use as a pilot control device. For this type of application proportional action involving small movements of the disk for the null condition is required. The theory for the steady-state linearized analysis of both the fluid and electromagnetic characteristics is developed. Experimental verification of the electromagnetic model is also described.

Modifying a Tilting Disk Mechanical Heart Valve Design to Improve Closing Dynamics

2008 ◽  
Vol 130 (5) ◽  
Author(s):  
Luke H. Herbertson ◽  
Steven Deutsch ◽  
Keefe B. Manning
Keyword(s):  
Heart Valves ◽  
Liquid Core ◽  
Mechanical Heart Valve ◽  
Blood Damage ◽  
Mechanical Valves ◽  
Mitral Position ◽  
Disk Valve ◽  
Cavitation Intensity ◽  
The Moment ◽  
The One

The closing behavior of mechanical heart valves is dependent on the design of the valve and its housing, the valve composition, and the environment in which the valve is placed. One innovative approach for improving the closure dynamics of tilting disk valves is introduced here. We transformed a normal Delrin occluder into one containing a ”dynamic liquid core” to resist acceleration and reduce the moment of inertia, closing velocity, and impact forces of the valve during closure. The modified occluder was studied in the mitral position of a simulation chamber under the physiologic and elevated closing conditions of 2500 mm Hg/s and 4500 mm Hg/s, respectively. Cavitation energy, detected as high-frequency pressure transients with a hydrophone, was the measure used to compare the modified valve with its unaltered counterpart. The cavitation potential of tilting disk valves is indicative of the extent of blood damage occurring during valve closure. Initial findings suggest that changes to the structure or physical properties of well established mechanical valves, such as the one described here, can reduce closure induced hemolysis by minimizing cavitation. Compared with a normal valve, the cavitation intensity associated with our modified valve was reduced by more than 66% at the higher load. Furthermore, the modified valve took longer to completely close than did the standard tilting disk valve, indicating a dampened impact and rebound of the occluder with its housing.

Two-Component Laser Velocimeter Measurements Downstream of Heart Valve Prostheses in Pulsatile Flow

1986 ◽  
Vol 108 (1) ◽  
pp. 59-64 ◽  
Author(s):  
W. G. Tiederman ◽  
M. J. Steinle ◽  
W. M. Phillips
Keyword(s):  
Shear Stress ◽  
Pulsatile Flow ◽  
Turbulent Shear ◽  
Prosthetic Heart Valves ◽  
Shear Stresses ◽  
Axial Distance ◽  
Prosthetic Valves ◽  
Disk Valve ◽  
Two Component ◽  
Stress Levels

Elevated turbulent shear stresses resulting from disturbed blood flow through prosthetic heart valves can cause damage to red blood cells and platelets. The purpose of this study was to measure the turbulent shear stresses occurring downstream of aortic prosthetic valves during in-vitro pulsatile flow. By matching the indices of refraction of the blood analog fluid and model aorta, correlated, simultaneous two-component laser velocimeter measurements of the axial and radial velocity components were made immediately downstream of two aortic prosthetic valves. Velocity data were ensemble averaged over 200 or more cycles for a 15-ms window opened at peak systolic flow. The systolic duration for cardiac flows of 8.4 L/min was 200 ms. Ensemble-averaged total shear stress levels of 2820 dynes/cm2 and 2070 dynes/cm2 were found downstream of a trileaflet valve and a tilting disk valve, respectively. These shear stress levels decreased with axial distance downstream much faster for the tilting disk valve than for the trileaflet valve.

Long-Term Survivors After Valve Replacement With a Starr-Edwards Mitral Disk Valve Prosthesis

2006 ◽  
Vol 30 (6) ◽  
pp. 484-487 ◽  
Author(s):  
Shigeaki Aoyagi ◽  
Shuji Fukunaga ◽  
Eiki Tayama ◽  
Koichi Arinaga ◽  
Takeshi Oda ◽  
...  
Keyword(s):  
Valve Replacement ◽  
Valve Prosthesis ◽  
Disk Valve ◽  
Long Term Survivors

Laser Anemometry Measurements of Steady Flow Past Aortic Valve Prostheses

1993 ◽  
Vol 115 (3) ◽  
pp. 290-298 ◽  
Author(s):  
Y. T. Chew ◽  
H. T. Low ◽  
C. N. Lee ◽  
S. S. Kwa
Keyword(s):  
Steady Flow ◽  
Heart Valves ◽  
Flow Region ◽  
Ball Valve ◽  
Prosthetic Heart Valves ◽  
Shear Stresses ◽  
Normal Stresses ◽  
Reversed Flow ◽  
Disk Valve ◽  
Wall Shear

An experimental investigation was conducted in steady flow to examine the fluid dynamics performance of three prosthetic heart valves of 27 mm diameter: Starr-Edwards caged ball valve, Bjork-Shiley convexo-concave tilting disk valve, and St. Vincent tilting disk valve. It was found that the pressure loss across the St. Vincent valve is the least and is, in general, about 70 percent of that of the Starr-Edwards valve. The pressure recovery is completed about 4 diameters downstream. The velocity profiles for the ball valve reveal a large single reversed flow region behind the occluder while those for the tilting disks valves reveal two reversed flow regions immediately behind the occluders. Small regions of stasis are also found near the wall in the minor opening of Bjork-Shiley valve and in the major opening of St. Vincent valve. The maximum wall shear stresses of the three valves at a flow rate of 30 l/min are in the range 30–50 dyn/cm2 which can cause hemolysis of attached red blood cells. The corresponding maximum Reynolds normal stresses are in the range of 1600–3100 dyn/cm2. The Reynolds normal stresses decay quickly and return approximately to the upstream undisturbed level at about 4 diameters downstream while the wall shear stresses decay at a slower rate. The maximum Reynolds normal stresses occur at about 1 diameter downstream while the maximum wall shear stress is at about 2 diameters downstream. In general, the St. Vincent valve has better performance. A method to compensate for refractive index variations and curvature effect of the sinus region of the aorta root using laser doppler anemometer measurements is also proposed.

Numerical Analysis of Three-Dimensional Bjo¨rk–Shiley Valvular Flow in an Aorta

1997 ◽  
Vol 119 (1) ◽  
pp. 45-51 ◽  
Author(s):  
E.-B. Shim ◽  
K.-S. Chang
Keyword(s):  
Shear Stress ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Leading Edge ◽  
Vortical Flow ◽  
Navier Stokes ◽  
Jet Flows ◽  
Computational Results ◽  
Navier Stokes Equations ◽  
Disk Valve

Laminar vortical flow around a fully opened Bjo¨rk–Shiley valve in an aorta is obtained by solving the three-dimensional incompressible Navier–Stokes equations. Used is a noniterative implicit finite-element Navier–Stokes code developed by the authors, which makes use of the well-known finite difference algorithm PISO. The code utilizes segregated formulation and efficient iterative matrix solvers such as PCGS and ICCG. Computational results show that the three-dimensional vortical flow is recirculating with large shear in the sinus region of the valve chamber. Passing through the valve, the flow is split into major upper and lower jet flows. The spiral vortices generated by the disk are advected in the wake and attenuated rapidly downstream by diffusion. It is shown also that the shear stress becomes maximum near the leading edge of the disk valve.

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