Design Of Centrifugal Blood Pump Based On Hemolysis Estimation

Cardiovascular disease is becoming one of the leading causes of human death. Heart attacts reach 1% in the world, the mortality rate could achieve 75% when patients with Heart failure which is cause by adanced heart disease in five years, heart transplant is the only treatment mean, however the serious lack of donors makes many patients dies when waiting donor. Therefore, blood pump with temporary or permanent substitute for nature cardiac function was born. The artificial heart develop from the beating blood pump to suspension rotating blood pump, constantly solve the clinical application problem to help patients out of disease, however hemolysis and thrombosis has been the major problems in the clinical application of the blood pump.Researche shows that the vortex flow and the stagnation flow in the blood pump have great influence in hemolysis and thrombosis, and scholar had given hemolysis estimation model, which show that hemolysis is a power function relation of shear stress the red cell suffered and contact time. This paper designs and optimizes the centrifugal rotating blood pump to improve the hemolysis characteristics and the hydraulic experiment and hemolysis test were made to analysis the hydraulic characteristics and hemolysis characteristics. This paper mainly makes the following research:1)Using the design theory of blood pump, which including the One-dimensional design theory and the speed coefficient method, to design the blood pump. This paper proposed an average shear stress model, assuming that the average shear stress that red blood cell suffered when flowed through the impeller approximately equivalent to it got kinetic energy increment per unit volume and unit distanceresents. In order to improve the hemolysis performance of the blood pump, this paper reduce the time of red blood cells flowing through the impeller and the average shear stress they suffered in the process. Based on average shear stress model, this paper for optimized the blood pump to improve the hemolysis performance. 2) Use CFD and hemolysis estimation model to analysis flow field and hemolysis characteristics. this paper studies hydraulic characteristics and hemolysis performance when the impeller and volute in different clearances, and analyses hydraulic characteristics and hemolysis characteristics when the pump with the different impeller number, then find suitable clearance and impeller numbes to reach the good hemolysis performance and good hydraulic quantity.3) Build hydraulic experimental platform and hemolysis test rig, and make hydraulic experiment and hemolysis test to analysis hydraulic characteristics and hemolysis characteristics of the blood pump.