Studies Of Implantable Axial Blood Pump’s Flow Fields Resulted From The Vibration By External Electromagnetic Force

The hemolysis is an important aspect in the study of blood pump. Researchers can use Computational Fluid Dynamics to simulate the flow fields of blood pump, to get the parameters of flow fields. By analyzing the parameters, the hemolysis index of blood pump can be estimated on a computer. But when simulating the flow fields of blood pump, most of the researchers supposed the blood pumps were fixed, didn’t consider the vibration caused by the implanted environment, high rotate speed, disequilibrium driving force and other factors of blood pump.In this paper, the blood pump studied was axial flow, implantable, driven by external electromagnetic field. Based on the blood pump in elastic implanted environment, the research on vibration of blood pump caused by uneven electromagnetic driving force was carried out. Then, the impact of vibration on the flow fields of blood pump and the deformation, stress state of the red blood cell was studied. Finally, the impact of vibration on the hemolysis of blood pump was analyzed.The main research contents are shown as follows:1. Based on the electromagnetics, mechanical system dynamics and other knowledge, the electromagnetic force of the blood pump’s permanent-magnet rotor in driven electromagnet field was calculated, which is verified by the means of simulation. The model of blood pump’s elastic implanted environment was build. Combining with the force of rotor, the dynamic system of blood pump’s vibration was established. Through building the system and solving the system equation in Simulink, the vibration characteristics of blood pump in different rotate speed is studied.2. By using the FLUENT, the vibration impact on the flow fields of blood pump was simulated. By changing the parameters of vibration velocity (amplitude and the frequency), the relationship between the parameters of vibration velocity and parameters of flow fields (velocity magnitude, volume fraction of phases and wall shear stress) was observed and analyzed. Then the influence of vibration on the hemolysis of blood pump was analyzed.3. The model of single red blood cell in vibrated flow field was built. The simulation of the flow fields was carried out by using FLUENT. According to the parameters of flow fields, the deformation and stress state of red blood cell, the damage of red blood cell in vibrated flow fields study was studied.4. The elastic implanted environment of the blood pump was simulated experimentally. The experiment system of measuring the vibration of blood pump in simulated environment was established. By using the experiment system, the data of acceleration components in different rotate speed and the parameter of the simulated model were collected. Processing the collected data, and comparing them with the theoretically solved data, the theoretical study was verified.