| Blood pump is the core device in the cardiopulmonary bypass system,its performance will directly affect the therapeutic effect in clinical application.A good blood pump can not only meet the requirements of blood flow,but also cause relatively small damage to blood.Previous studies mostly used experimental methods,but this method has many limitations.Therefore,using simulation analysis method to evaluate the performance and optimize the design of blood pump has been an important topic.In this paper,the piping system of the rolling blood pump is taken as the research object,and the flow field of the rolling blood pump is simulated and analyzed.The influence of various parameters of the roller pump on its performance is studied,and the structural parameters are optimized,so as to improve the hydraulic performance of the roller pump and reduce the shear stress damage to the blood in the pipe.The main contents of this paper are as follows:(1)The two-dimensional model of roller pump is established.Based on the analytic geometry method,the working process of roller pump is analyzed and the working principle of roller pump is studied.Combined with hydrodynamics,the energy loss of blood in the pipeline of cardiopulmonary bypass was studied,and the hydraulic performance requirements of the selected roller pump were preliminarily determined.(2)The two-dimensional CFD model of roller pump is established.Two different methods,steady-state and transient,are used to simulate and analyze the flow field inside the hose of roller pump.The results of steady-state and transient simulation and analysis are compared,which lays a foundation for the study of the influence of parameters and structure of roller pump.The hydraulic performance test is carried out on the roller pump to verify the validity and reliability of the established model.(3)Based on the steady-state simulation analysis,supplemented by the transient simulation analysis,the single factor test method is used to study the influence of various parameters of roller pump on the outlet flow and the shear stress of blood.Based on the results of single factor test,three structural parameters are selected and orthogonal test table is established based on orthogonal analysis.The simulation results of different test schemes are obtained in turn,and the influence of three selected parameters on the performance of roller pump is studied by range analysis and variance analysis.According to the analysis results,the optimal structural parameters are selected to realize the optimal design of roller pump structure.(4)The optimized model was compared with the original model,and the outlet flow and the shear stress of blood were studied before and after the optimization.(5)The flow field characteristics of the output pipeline system were simulated and analyzed.The eddy current area and negative pressure area were observed.The shape of the output sheath outlet was improved according to the simulation results.The flow field characteristics of the improved pipeline are simulated and compared with the original results to clarify the advantages of the improved model,so as to guide the clinical application. |
