Development of a new simulation device of blood time-varying shear force
Objective To develop a Couette type blood time-varying shear force simulator,and to provide an experimental platform for studying flow-induced blood injury.Methods The blood shear device is mainly composed of three parts,which are drive control module,shear flow generation module and exposure time control module.Among them,the most central part is the shear flow generation module,which is originally designed as an axial flow blood pump and redesigned as an axial flow Couette device (hemolytic pump) .There is a gap between the hemolytic pump rotor and the housing to generate flow-induced shear forces.The hemolytic pump is made of medical titanium alloy as a whole,and ruby sliding bearings are used in the front and rear guide blades.The exposure time is controlled by the flow rate and volume of the injection pump,and the rotation of the hemolytic pump rotor is driven by the servo motor combined with the synchronous belt transmission structure.The computational fluid dynamics (CFD) numerical simulation software Fluent is used to simulate the internal flow field of the hemolysis pump.The response speed and stability of the blood shear device are verified by experiments,and the hemolysis experiment is carried out.Results CFD results show that a uniform region of high shear forces can be generated within a small gap,while the shear forces are lower elsewhere.Due to the use of servo motor drive,the device can produce up to 300 Pa,25 Hz time-varying shear force.The variation coefficient of the experimental results is less than 10％ when the equipment is tested several times under the same conditions.By adjusting the hemolysis pump speed and blood flow velocity,blood from different individuals is used to quantify the shear-induced hemolysis under the matrix of exposure time (1,2 s) and shear force (50,100,150,200,250 Pa) .The difference between individuals is the key factor affecting the experimental results under the same experimental conditions.Conclusions The blood time-varying shear stress simulation device can meet the relevant experimental requirements.In the process of experiment,it is necessary to pay attention to the influence of blood' s own differences on the experimental results.
万方数据
维普
