人工心脏液力悬浮支承结构设计及其血液相容性研究

发布时间：2018-04-16 15:00

本文选题：人工心脏 + 液力悬浮　；参考：《浙江大学》2012年博士论文

【摘要】：本课题以人工心脏液力悬浮轴承为研究对象,针对悬浮支承结构设计及其血液相容性展开系统研究。开展了悬浮支承轴承结构设计、结构参数优化、稳定与脉动条件下的转子悬浮位移测试、液力悬浮轴承结构的血液相容性等研究,为人工心脏液力悬浮支承结构设计和血液相容性研究提供了有价值的参考。本文首先根据液力悬浮支承流场的特点建立了悬浮支承间隙内流体流动的数学模型,并在此基础上初步开展了向心轴承和止推轴承的结构设计；其次,开展人工心脏球型液力悬浮轴承结构设计,并进行了相关的实验研究；对于锥型液力悬浮轴承结构,通过数值模拟对比分析了不同最小间隙内流体流动特性及悬浮支承力；对于主轴开设螺旋槽型悬浮支承轴承结构,结合正交实验设计给出了一组最优螺旋槽设计尺寸；在此基础上,提出了一种低血栓螺旋槽液力悬浮轴承结构设计方法,并对上止推轴承内流体进行了数值模拟,分析三种典型螺旋槽结构设计的流量、悬浮支承力和压力之间的关系,同时引入此类悬浮支承结构的承载力-流量特征平面,并通过该特征平面对比分析了多种类型液力悬浮支承结构设计的流量与悬浮支承力范围。再次,对稳定运转和脉动干扰下的液力悬浮支承位移进行了实验研究,测试了不同工况下,稳定悬浮支承液膜在轴向与径向的运动参数和悬浮位移之间的关系,并分析了相应的轴承悬浮稳定性能。最后,对液力悬浮支承间隙内流体的血液相容性进行了数值模拟,分析了不同悬浮支承结构和不同进出口压力对悬浮支承流体的溶血特性影响,并通过动物实验对液力悬浮支承结构的抗血栓性能进行了评价。课题的主要研究工作如下： 1.液力悬浮支承研究。在分析悬浮支承间隙流场流动特性的基础上,建立了稳态载荷下液力悬浮支承流场的数学模型,并初步开展了向心轴承和止推轴承的结构设计。在此基础上,开展了人工心脏球型液力悬浮轴承结构设计和实验研究、锥型和主轴开设螺旋槽型悬浮轴承结构人工心脏的结构设计和数值模拟。通过实验研究,研究设计的球型液力悬浮支承结构是否满足悬浮要求；通过数值模拟,开展锥型悬浮支承结构最小间隙与悬浮支承力之间关系的研究,给出主轴开设螺旋槽型液力悬浮支承结构的最大悬浮支承力结构设计参数,并对比分析了两种悬浮支承结构内流体的流量。 2.低血栓螺旋槽液力悬浮轴承结构设计及数值模拟。设计了一种新型螺旋槽轴承,并将其应用到以长期植入人体为目标的人工心脏转子支承中。螺旋槽设计的特点是其宽度随着半径的变大而逐渐变窄,从而可以利用动压效应增加悬浮支承力,且螺旋槽的旋线方向与转子旋转方向相同可以促进流体流动,增加悬浮间隙中的流量,从而有效避免血栓。通过三维数值模拟对新型螺旋槽设计与传统设计进行对比,并引入表征流量和悬浮支承力关系的特征平面,对多种类型的螺旋槽轴承设计的进行承载力-流量对比,将对比结果统一于同一个承载力-流量特征平面中,通过该特征平面直接给出各种类型螺旋槽设计的承载力/流量变化。 3.液力悬浮支承位移测试实验研究。选用具有较好承载力/流量特性的液力悬浮支承结构参数,设计并加工液力悬浮测试泵,搭建稳态条件和脉动条件下轴向、径向测试实验台,测试悬浮转子在轴向的绝对位移和径向间隙的变化情况。对于稳态条件下的位移测试,通过研究转速、螺旋槽结构参数与转子悬浮位移的关系,给出各种悬浮支承结构能够稳定支承的转速范围、径向转子运动的间隙变化范围,研究转子径向运动轨迹的变化规律；对于脉动条件下的位移测试,通过测试不同脉压下轴向位移量和径向间隙变化量,分析对比不同工况下悬浮支承液膜的变化情况,通过计算得出径向半径间隙与偏心距的差值变化情况,分析转子的悬浮稳定性能并给出转子能够稳定悬浮的转速调节范围。 4.液力悬浮支承的血液相容性研究。采用拉格朗日粒子追踪法对悬浮支承间隙内的血液进行分析,根据经验公式,计算不同悬浮支承间隙结构内剪切应力对红细胞的作用及每个粒子在流场中停留的时间,判断所设计的螺旋槽结构溶血估算值是否能够满足悬浮支承对溶血性能的要求。在此基础上,通过动物实验对螺旋槽结构进行抗血栓性能评价。
[Abstract]:The research on the structure of suspension bearing , the optimization of the structure parameters , the stability of the rotor suspension displacement and the blood compatibility of the hydrodynamic suspension bearing structure have been carried out in order to provide valuable reference for the study of the structure design and the blood compatibility of the artificial cardiac hydrodynamic suspension bearing .

In this paper , the mathematical model of fluid flow in floating bearing clearance is established according to the characteristics of liquid force suspension support flow field , and the structure design of centripetal bearing and thrust bearing is carried out preliminarily .
Secondly , the structure design of artificial heart spherical hydrodynamic suspension bearing is carried out , and relevant experimental research is carried out .
For the cone - shaped hydrodynamic suspension bearing structure , the fluid flow characteristics and the suspension supporting force in different minimum clearances are analyzed by numerical simulation .
According to the orthogonal experimental design , a set of optimal spiral groove design sizes are given .
On the basis of this , a design method of liquid - force suspension bearing with low thrombus spiral groove is presented , and the relationship between the flow rate , suspension support force and pressure of three typical spiral groove structures is analyzed .

The main research work of the subject is as follows :

1 . Hydraulic suspension support study .

On the basis of analyzing the flow characteristics of the floating bearing gap , a mathematical model of the hydrodynamic suspension bearing flow field under steady state load is established , and the structure design of the centripetal bearing and thrust bearing is preliminarily carried out . Based on this , the structural design and numerical simulation of the artificial heart with the spiral groove type suspension bearing structure of the artificial heart ball type hydrodynamic suspension bearing are carried out .
Through numerical simulation , the relationship between the minimum clearance and the suspension support force of the conical suspension support structure is studied . The design parameters of the maximum suspension supporting force of the spiral groove type hydrodynamic suspension support structure are given , and the flow rate of the fluid in the two suspension supporting structures is compared .

2 . Structure design and numerical simulation of hydraulic suspension bearing with low thrombus spiral groove .

A novel spiral groove bearing is designed and applied to artificial heart rotor support aiming at long - term implantation of human body . The spiral groove design features that its width is gradually narrowed as the radius becomes larger , so that the floating support force can be increased by the dynamic pressure effect , and the flow rate in the suspension gap can be increased by using the three - dimensional numerical simulation , and the comparison result is unified in the same bearing capacity - flow characteristic plane , and the bearing capacity / flow rate variation of various types of spiral groove designs is directly given through the characteristic plane .

3 . Experimental study on displacement test of hydraulic suspension support .

In this paper , the parameters of hydraulic suspension supporting structure with better bearing capacity / flow characteristics are selected , the hydraulic suspension test pump is designed and processed , the axial and radial test bench is built and processed under steady state conditions and pulsating conditions , and the relationship between the absolute displacement and radial clearance of the suspension rotor in the axial direction is tested .
For the displacement test under pulsating conditions , by testing the axial displacement and radial gap variation under different pulse pressures , the variation of the suspension support liquid film under different working conditions is analyzed , and the difference between the radial clearance and the eccentricity is calculated , and the suspension stability of the rotor can be analyzed and the range of rotation speed regulation of the rotor can be stably suspended .

4 . Study on blood compatibility of hydraulic suspension support .

According to the empirical formula , the effect of shear stress on red blood cells and the time of each particle staying in the flow field were calculated by using the Lagrange particle tracking method .

【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2012
【分类号】：R318.11

【引证文献】