Experimental investigation of unsteady flow behaviour within a sac-type ventricular assist device (VAD).

摘要: Abstract The flow behaviour of human blood in a pneumatically driven sac-type ventricular assist device (VAD) has been simulated by non-Newtonian polymer (Separan) solution, and investigated both one-component laser Doppler anemometer (LDA) back-scattering mode visualisation. was pneumatic driver with squarewave output pressure, operated at pumping rate 70 bpm, systolic duration 35% the cycle. preload average afterload to were set 10 mm Hg 100 Hg, respectively. flowrate 4.05 l min−1. wall peripheral central parts chamber VAD well ‘washed’ main vortex developed during filling components perpendicular base produced diaphragm motions, Flow recirculation regions found several locations. Around junction between tube sections chamber, an associated fluid particle deposition indicates underlying risk thrombus formation. This will be reduced modifying design. maximum turbulent shear stress estimated from normal (74 Nm−2), is unlikely cause significant damage for exposure times found. residence time closely related heart degree completion ejection/filling. At given rate, operating conditions which produce highest stroke volume give shortest times.