1. Development And In Vitro Performance Of A New Type Of Axial Flow Ventricular Assist Device 2. A Novel Integrated Rotor Of Axial Flow Blood Pump Designed With Computational Fluid Dynamics

Part 1Development and in vitro performance of a new type of axial flow ventricular assist deviceUsing computational fluid dynamics (CFD), we have continued development of an implanted axial flow blood pump. New hydraulic blade designs have been tested using computational fluid dynamics (CFD). A prototype of the improved pump was fabricated and used to conduct in vitro experiments to evaluate the performance of hydraulic performance. The numerical results for the axial blood pump and the prototype hydraulic testing indicate an acceptable design for the blood pump, representing a significant step in the development phase of this device. Part 2A Novel Integrated Rotor of Axial Flow Blood Pump Designed with Computational Fluid DynamicsDue to the smaller size, smoother artificial surface and higher efficiency, axial blood pumps have been widely applied in clinic in recent years. However, because of its high rotor speed, axial flow pump always has a high risk for hemolysis, which the red blood cells (RBCs) devastated by the shearing of tip clearance flow. We reported a novel design with the integrated blade-shroud structure to solve this problem by abolishing the radial clearance between blade and casing using the techniques of Computational Fluid Dynamics (CFD). The numerical simulation result of the new designed structure showed an unexpected back flow at the blade tip, and in order to eliminate this back flow, four flow passes had been attempted, and the expansion angles (which reflect the radial amplification of the flow pass, on the meridianal section, should be defined as the angle between the center line of the flow pass and the axial direction) of the blades are 0°, 8°, 15°, 20°, respectively. In the CFD result, it could be easily found as the expansion angles increasing the backflow was restrained gradually, and was eliminated at last. After numerous "cut and try" circles, the pump model was finally optimized. The numerical simulation of this model also showed a stable hydraulic characteristic.