Design and optimization of a novel cavopulmonary assist device for Fontan circulation: CFD and PIV studies
Abstract
Numerical and experimental studies are carried out to assess the hydraulic, hemodynamic performance, biocompatibility and the flow field of a viscous impeller pump (VIP) for mechanical cavopulmonary assist in patients with a univentricular Fontan circulation. The VIP is a bi-conical six vaned impeller with a nitinol cage that may be placed percutaneously in the cavopulmonary junction using a catheter based approach. Computational fluid dynamics (CFD) predictions of impeller performance are shown to be in agreement with measured pressure-flow data obtained in a Fontan mock-circulation system. Parametric studies using CFD models explore the effects of rotation speed, flow rate and pump geometry on VIP performance. Particle image velocimetry (PIV) measurements are compared to CFD results within the idealized Fontan geometry using a refractive index matched blood analog. Data is presented with a static VIP and rotating VIP using phase locking techniques. The CFD models used are in agreement for global hydraulic values but poorly predict flow patterns in the vicinity of a rotating VIP. Additional design studies intending to balance pump performance, biocompatibility with the manufacturability limitations of a percutaneous expandable impeller are reported. The numerical models and experimental studies confirm excellent performance of the VIP with augmentation of Fontan pressure up to 35 mmHg for flow rates up to 4.4 L/min and operational speeds of 5,000 RPM at adult scales. Neonatal scale studies also show excellent performance while maintaining biocompatibility.
Degree
M.S.M.E.
Advisors
Frankel, Purdue University.
Subject Area
Biomedical engineering|Mechanical engineering
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