Research On Biorheological Characteristic Testing Method And Its Applications

Rheology is a science that studies the time-related deformation and flow ofnon-Newtonian fluids under the conditions of stress, strain, and temperature. It is aninterdisciplinary subject which includes some parts of physics, mechanics, medicine,biology, and engineering. The flow of viscoelastic fluids, viscoplastic fluids, bloods,and most of biofluids demonstrates the characteristics of non-Newtonian fluid. Thetesting of some rheological characteristics, such as the rheological characteristics ofnon-Newtonian fluids, mechanical analysis of fluid flow and deformation,constitutive equations of fluids, parameters and functions of material,viscosity-temperature characteristics of fluids, flow curve, coagulability,viscoelasticity, and thixotropy, demands prompt solution. Especially in the field ofbiomedical engineering, the test problems about the biorheological characteristics,such as the dynamics of blood flow, deformation laws of blood cell, mechanicalproperts of blood, other body fluids, and all kinds of soft and hard tissues, andrelations between the rheological characteristics of biofluids and illnesses, are raisedin succession. Hemorheology, cell rheology, and the rheological mechanism andparameter measurement during the process of blood coagulation, have attractedmany researcher’s attention. This thesis focuses on the research on thebiorheological characteristic testing method and its applications, along with theresearch project Rheological Characteristic Testing Methods in Hemorheology, CellRheology, and the Process of Blood Coagulation.An overall review of the rheology is given. The classification and researchsignificance of the non-Newtonian fluid rheology are introduced. Research topics ofthe biorheological characteristic testing, such as the hemorheology, cell rheology,and the rheological mechanism and parameter measurement during the process ofblood coagulation, are analyzed in detail. The relations between the biorheology andsome illnesses such as cardiovascular and cerebrovascular disease, malignant tumor,and diabetes, are revealed. The physiological and pathological actions of thebiorheology towards the hemostasis, blood coagulation, and formation of thrombuswhile the blood flows are discussed.Based on the research object and method of rheology, the measurement theory of non-Newtonian fluid rheology is introduced. The mechanical characteristics of thenon-Newtonian fluid deformation and flow are analyzed. Basic differentialequations of the non-Newtonian fluid flow are deduced. Constitutive equations ofthe pure viscous non-Newtonian fluids are built. Some typical flows ofnon-Newtonian fluid, and rheological characteristics such as viscoelasticity andthixotropy, are analyzed. The main rheological parameters of the steady state shearflow field and the rheological parameter characterization methods of the smallamplitude oscillatory flow field and fluid viscoelasticity are studied.According to the research on the biorheological characteristic testing technique, ahemorheological test method based on steady state shear velocity attenuationmethod is presented. A test method of cell rheological characteristic, such as cellmorpha, deformation and aggregation, based on the technique of laser diffractionand scattering is proposed. Rheological characteristic test methods during theprocess of blood coagulation, such as double magnetic circuits magnetic beadoscillatory method, optical scattering measuring method and chromogenic substratemeasuring method, based on the small-amplitude oscillatory flow field, are alsodemonstrated. The problems of some test techniques and methods of biorheologicalcharacteristic, such as the blood flow, cell deformation, cell aggregation and bloodcoagulation, are resolved.Biorheological characteristic test models are given based on steady state shearflow field, elongational flow field, and small-amplitude oscillatory flow field. Ahighly sensitive and reliable Couette biofluid rheological characteristic test systemand dynamic data modeling system are built. The biofluid rheological characteristictest and dynamic data modeling are accomplished by using the models of stressdriving, real-time frequency sweep, small amplitude oscillation, and forcedoscillation.Experiments are conducted to verify the proposed hemorheological test methodbased on steady state shear velocity attenuation method and cell rheological testmethod based on laser diffraction method. To sovle the problems that theinstruments for non-Newtonian fluid rheological characteristic testing cannot becalibrated and its testing results cannot be traced, a kind of stable and reliablenon-Newtonian fluid standard substance is developed and a non-Newtonian fluidcalibration method is proposed. The application research on hemorheological test system based on steady stateshear velocity attenuation method is completed. The system realizes the full-range,point-by-point scanning, rapid and steady-state measurement of the hemorheologicalcharacteristics using the proposed velocity attenuation cone-plate testing method.The system has some advanced functions such as automatic sampling, blending,testing, and cleaning, together with the function of liquid level detecting. It also hasthe functions of non-Newtonian fluid standard substance calibration and adjustment.The application research on blood coagulation test system based on doublemagnetic circuit small amplitude oscillation method is also completed. Therheological characteristic test during the process of blood coagulation is achieved byusing the proposed double magnetic circuit magnetic bead oscillatory method. Thesystem has an advanced3D sampling unit, driver embedded point-to-point function,S-curve acceleration and line-circle interpolation motion function, and weak signalsampling-amplifying function. It has the advantages of powerful functions, real-timemultitask operation, rapid detection, and high accuracy.This thesis lays a good foundation to build the necessary theoretical principle thatwill benefit the research on the biorheological characteristic testing method and itsapplication. It has important directive significance to the development of thebiofluid rheological characteristic testing method.