Visualization of cavitation on mechanical heart valve

Cavitation has been documented for GK mechanical heart valve in an in vitro flow system simulating the closing event in mitral position. From picture taken with digital camera, cavitation clouds moved outwards along the seat stop on the occlude surface after closure. Cavitation was investigated and explained by squeezing flow from the impact between occlude and seat stops at the closure of mechanical heart valve. Its mechanism is vortex cavitation from wall jet. Velocity of squeezing flow was estimated to be up to 9 m/s causing local low pressure contributing much to cavitation. Closing velocity of occlude was an important factor for cavitation potential of GK valve. Cavitation duration varied with the ventricular loading rate and was up to 440μs at loading rate of 2750mmHg/s. The loading rate threshold of cavitation was 420mmHg/s. This value was lower than that of normal physiological condition of 750mmHg/s in animal test. It was concluded that there was possibility of cavitation for GK mechanical heart valve.