Microvascular Blood Flow Model Based On Statistical Distribution Of Erythrocyte Movement

For capillary blood flow,the exchange of substances in tissues（especially oxygen）is achieved by the movement of red blood cells in capillary blood vessels.Therefore,compared with the diagnosis and treatment of many diseases,the blood flow parameters of human tissue microvessels are one of the most important clinical diagnostic parameters.Compared with the directional flow of red blood cells in main blood vessels,the structure of microvessels is complex,and there is no unified blood flow model to describe it.In this paper,a computer simulation model of reticular microvascular structure is established,and the movement trajectory of red blood cells（RBC）is simulated based on fluid mechanics and particle tracking theory.In addition,a statistical analysis method for RBC particle displacement data was established,and a new microvascular hemodynamic model combining Brownian motion and random trajectory model was obtained.Based on this model,the relationship between the proportion of the two motions in the mixed model and the macroscopic flow velocity was investigated.In this paper,the erythrocyte movement model and blood flow detection technology combined will provide accurate hemodynamic basis for the early diagnosis and treatment evaluation of various diseases.The specific innovation work of this paper is as follows:（1）The microcirculation is extremely small,and the movement changes of red blood cells cannot be directly observed by human eyes,requiring the use of high-resolution electron microscopy.This limitation poses great difficulties for the study of microvascular hemodynamics.Based on this,this paper,by using the finite element software COMSOL laminar flow in the physical field and particle tracking physical fields module microvascular network structure of the computer simulation model is established and simulated the motion trajectory of red blood cells,and got the movement of the red blood cell particles in different time coordinate data,and is conducive to further analysis and research of microvascular blood flow dynamics,The development of microvascular model simulation technology provides valuable information for understanding the mechanism of tissue microcirculation.（2）Currently commonly used microvascular hemodynamic models: Random ballistic flow and Brownian motion are not precisely reflect the characteristics of the microvascular network structure,this paper established two kinds of single model mixed according to certain proportion superposition microvascular blood flow dynamics mathematical model of the hybrid model is verified through the simulation can reflect the red blood cells more comprehensive in motion in the microvascular network structure system.This is not only helpful for accurate calculation of microvascular blood flow value,but also of great significance for medical clinical diagnosis and treatment of many major diseases,as well as basic and continuous research in the frontier of human life science.（3）According to different time in the computer simulation model of red blood cells,the coordinates of the data to establish the statistical analysis method of displacement of red blood cells,successful separation of the single particle displacement data of the model,and based on this through setting different velocity in the model,investigates the proportion of each model number of particles in the mixed model,and its relationship with macro velocity,It provides a theoretical basis for elucidating the mechanism of microcirculation.（4）Design imitation experiments to verify the simulation results.According to the optical parameters of human tissue（absorption coefficient and scattering coefficient）,the imitation solution was configured,and the imitation experiment device was designed and built.Through the realization of several flow rate experiments,the experimental data were processed and the unknown parameters in each model were obtained by fitting,which verified the authenticity of the simulation experiment.In this article,in view of the present commonly used both hemodynamic model are defects can not accurately reflect the characteristics of the microvascular network structure of the research,through the establishment of red blood cells in the capillary dynamic model of the mixed concrete is stochastic trajectory model and brown motion model respectively in accordance with certain proportion,separate affects RBC movement and according to the principle of fluid mechanics,A microvascular computer simulation model was established by using the laminar flow physical field module and particle tracking physical field module of multi-physical field finite element software COMSOL to complete the hemodynamic analysis and describe the motion state of red blood cells in the microvascular.Structure,on this basis,according to the simulation model of red blood cells derived particles displacement,the position of each particle in different time coordinate data,after the particle coordinates data processing,the method of using statistical distribution,the success of the simulation model of the number of particles Brownian motion and Random ballistic flow distinguish the number of particles,The unknown parameters in the mixed model are solved.At the same time,the simulation of several velocity models was carried out to verify the relationship between velocity and erythrocyte movement.The results showed that the proportion of particles in Brownian motion model decreased with the increase of velocity,while the proportion of particles in ballistic model increased.Specifically,when the flow rate increases gradually from 100 m L /h to 400ml/h,the proportion of particles in Brownian motion decreases gradually from 89% to 59%.At the same time,the proportion of particles in random trajectory model increases gradually from 11% to 41%.In conclusion,a mixed flow model of red blood cells in microvessels was established in this paper,and the unknown parameters in the mixed model were solved by computer simulation for the first time,and the law of velocity and movement of red blood cells was clarified.And through the design of imitation experiment,the authenticity of the simulation results is fully proved.This study is helpful to microvascular blood flow monitoring,extract accurate blood flow information,and provide valuable information for future physiological and clinical research.