LDA Measurements of Mean Velocity and Reynolds Stress Fields Within an Artificial Heart Ventricle

1994 ◽  
Vol 116 (2) ◽  
pp. 190-200 ◽  
Author(s):  
J. T. Baldwin ◽  
S. Deutsch ◽  
D. B. Geselowitz ◽  
J. M. Tarbell
Keyword(s):  
Artificial Heart ◽  
Laser Doppler Anemometry ◽  
Operating Conditions ◽  
Reynolds Stresses ◽  
Assist Device ◽  
Mean Velocity ◽  
Ventricular Assist ◽  
Penn State ◽  
Entire Flow ◽  
Flow Cycle

Laser Doppler Anemometry measurements of mean (ensemble average) velocities and turbulent (Reynolds) stresses at 140 locations within the left ventricle of the Penn State 70 cc electric artificial heart/ventricular assist device are reported at 8 times during the cardiac cycle. Mean velocity patterns indicate that the surfaces of the blood sac and valve tracts are exposed to significant levels of wall shear stress (good wall washing) during some portion of the flow cycle, and there is no location where the flow is stagnant over the entire flow cycle. This implies that thrombus deposition within the artificial heart should be suppressed. Turbulent stresses in the main pumping chamber and the outflow tracts of the tilting disk valves do not exceed 2000 dynes/cm2. The highest turbulent stresses (20,000 dynes/cm2) and smallest turbulent microscales (6 μm) are found in the regurgitant jets on the minor orifice side of the aortic valve during diastole and the mitral valve during systole. Taken together, the data suggest that improvements in artificial heart fluid mechanics will come through valve design and pump operating conditions, not pumping chamber design.

Sa1894 Gastrointestinal Bleeding in Ventricular Assist Device and Total Artificial Heart Implantations

2014 ◽  
Vol 146 (5) ◽  
pp. S-322
Author(s):  
Jatinder Lachar ◽  
Sanah Christopher ◽  
Maureen Flattery ◽  
Keyur Shah ◽  
Daniel G. Tang ◽  
...  
Keyword(s):  
Gastrointestinal Bleeding ◽  
Ventricular Assist Device ◽  
Artificial Heart ◽  
Total Artificial Heart ◽  
Assist Device ◽  
Ventricular Assist

Fluid Dynamic Analysis of the 50 cc Penn State Artificial Heart Under Physiological Operating Conditions Using Particle Image Velocimetry

2004 ◽  
Vol 126 (5) ◽  
pp. 585-593 ◽  
Author(s):  
Pramote Hochareon ◽  
Keefe B. Manning ◽  
Arnold A. Fontaine ◽  
John M. Tarbell ◽  
Steven Deutsch
Keyword(s):  
Particle Image Velocimetry ◽  
Artificial Heart ◽  
Particle Image ◽  
Flow Fields ◽  
Design Tool ◽  
Operating Conditions ◽  
Shear Rates ◽  
Heart Chamber ◽  
Image Velocimetry ◽  
Penn State

In order to bridge the gap of existing artificial heart technology to the diverse needs of the patient population, we have been investigating the viability of a scaled-down design of the current 70 cc Penn State artificial heart. The issues of clot formation and hemolysis may become magnified within a 50 cc chamber compared to the existing 70 cc one. Particle image velocimetry (PIV) was employed to map the entire 50 cc Penn State artificial heart chamber. Flow fields constructed from PIV data indicate a rotational flow pattern that provides washout during diastole. In addition, shear rate maps were constructed for the inner walls of the heart chamber. The lateral walls of the mitral and aortic ports experience high shear rates while the upper and bottom walls undergo low shear rates, with sufficiently long exposure times to potentially induce platelet activation or thrombus formation. In this study, we have demonstrated that PIV may adequately map the flow fields accurately in a reasonable amount of time. Therefore, the potential exists of employing PIV as a design tool.

The Fluid Dynamic Effects Within the 12cc Penn State Pediatric Ventricular Assist Device When Altering the End Diastolic Delay

2009 ◽  
Author(s):  
Benjamin T. Cooper ◽  
Breigh N. Roszelle ◽  
Tobias C. Long ◽  
Steven Deutsch ◽  
Keefe B. Manning
Keyword(s):  
Congenital Heart Disease ◽  
Birth Defect ◽  
Congenital Heart ◽  
Fluid Dynamic ◽  
Ventricular Assist Devices ◽  
Bridge To Recovery ◽  
Dynamic Effects ◽  
Assist Device ◽  
Ventricular Assist ◽  
Penn State

Congenital heart disease is the most common and leading cause of birth-defect related deaths [1]. While many of these patients have damaged or deformed hearts that require transplantation, recovery may be possible for a select population [2]. Extracorporeal membrane oxygenation or ventricular assist devices are often used in a bridge-to-recovery situation to sustain a patient with the expectation of recovery of natural ventricular function [3].

THE VISCOELASTIC EFFECTS WITHIN THE PENN STATE PEDIATRIC VENTRICULAR ASSIST DEVICE

ASAIO Journal ◽  
2006 ◽  
Vol 52 (2) ◽  
pp. 62A
Author(s):  
Jennifer A Long ◽  
Keefe B Manning ◽  
Akif Undar ◽  
Steven Deutsch
Keyword(s):  
Ventricular Assist Device ◽  
Assist Device ◽  
Ventricular Assist ◽  
Viscoelastic Effects ◽  
Penn State

Experimental and Numerical Investigation of a Cold Turbulent Jet Impinging on a Hot Plate

2012 ◽  
Author(s):  
D. I. Maldonado ◽  
J. K. Abrantes ◽  
L. F. A. Azevedo ◽  
A. O. Nieckele
Keyword(s):  
Flow Field ◽  
Laser Doppler Anemometry ◽  
Turbulence Models ◽  
Impinging Jets ◽  
Reynolds Stresses ◽  
Hot Plate ◽  
Mean Velocity ◽  
Velocity Statistics ◽  
Reliable Assessment ◽  
Anisotropic Structures

Impinging jets are an efficient mechanism to enhance wall heat transfer, and are widely used in engineering applications. The flow field of an impinging jet is quite complex and it is a challenging case for turbulence models validation as well as measurements techniques. In the present work, a detailed investigation of a cold jet impinging on a hot plate operating in the turbulent flow regime was conducted. The flow field was characterized by both Laser Doppler Anemometry and Particle Image Velocimetry (PIV) techniques in order to collect 1st and 2nd order velocity statistics to allow a reliable assessment of the numerical simulations. Comparison was performed with two turbulence methodologies: RANS (κ–ω SST model) and LES (Dynamic Smagorinsky model). The comparison was performed to assess LES feasibility and accuracy in capturing the anisotropic structures that several tested RANS models missed. The mean velocity, instantaneous velocity, Reynolds stresses and Nusselt profiles obtained numerically are compared with experimental data. A physical insight about the general flow dynamics was obtained with the extensive amount of information available from the LES.

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