Abstract
The tracer method was utilized for the quantitative analysis of the flow field within artificial heart (AH) using mock circulatory loop. The flow behavior was analyzed with a numerical method. The length and location of the particle paths on the flow-visualizing picture were measured with a digitizing tablet and the velocity vectors in several phases were computed from these data. The unknown velocity vector at each point of the mesh of the square grid pattern drawn tentatively on the photograph, was deduced from several adjacent velocity vectors by the least square method. The mesh point values of the stream function and vorticity were calculated from the mesh point velocity vectors by means of iterative integration and finite-difference approximation. The results thus obtained were displayed by a plotter using the linear interpolation method. It was concluded from this study that: (i) the current within AH flows along the inner surface and stagnates at the inlet during the filling period; (ii) presumably the circulating current removes the blood, and suppresses the formation of thrombus within AH; (iii) there is a need to modify the contour of the inlet portion of AH, because the blood flow thereabout stagnates; (iv) our flow-visualization and quantitative analysis proved useful to develop more efficient and thromboresist AH.
