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Journal of Mechanical Science and Technology

, Volume 20, Issue 8, pp 1118–1124 | Cite as

Mechanism for cavitation phenomenon in mechanical heart valves

  • Hwansung Lee
  • Yoshiyuki Taenaka
Article

Abstract

Recently, cavitation on the surface of mechanical heart valve has been studied as a cause of fractures occurring in implanted Mechanical Heart Valves (MHVs). It has been conceived that the MHVs mounted in an artificial heart close much faster than in vivo sue, resulting in cavitation bubbles formation. In this study, six different kinds of monoleaflet and bileaflet valves were mounted in the mitral position in an Electro-Hydraulic Total Artificial Heart (EHTAH), and we investigated the mechanisms for MHV cavitation. The valve closing velocity and a high speed video camera were employed to investigate the mechanism for MHV cavitation. The closing velocity of the bileaflet valves was slower than that of the monoleaflet valves. Cavitation bubbles were concentrated on the edge of the valve stop and along the leaflet tip. It was established that squeeze flow holds the key to MHV cavitation in our study. Cavitation intensity increased with an increase in the valve closing velocity and the valve stop area. With regard to squeeze flow, the bileaflet valve with slow valve-closing velocity and small valve stop areas is better able to prevent blood cell damage than the monoleaflet valves.

Key Words

Artificial Heart Mechanical Heart Valve Cavitation Bubble Squeeze Flow 

Nomenclature

h

Gap between a leaflet and valve stop (mm)

L

Length of the valve stop (mm)

V

Valve-closing velocity (m/s)

P

Pressure (Pa)

U

Squeeze flow velocity (m/s)

μ

Fluid viscosity (Pa•s)

ρ

Density of fluid (g/cm3)

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Copyright information

© The Korean Society of Mechanical Engineers (KSME) 2006

Authors and Affiliations

  1. 1.Department of Artificial OrgansResearch Institute, National Cardiovascular CenterOsakaJapan

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