卡森流体表观粘度随切变率增大而下降的原因分析

THE ANALYSIS 0F WHY THE APPARENT VISCOSITY OF CASS0NIAN FLUID DECREASES WITH THE INCREASE OF THE SHEAR RATE

森流体的经验公式为：其表观粘度ηa为该式中的卡森屈服值（τc）和卡森粘度（ηc），在一定切变率（γ）范围内，是不随γ而变化的常数。因此，ηa随γ增大而下降的原因只能用的关系来解释。这种反比关系必须在τc≠±的条件下才成立。否则，卡森流体变为牛顿流体。卡森粘度属动力性粘度。在圆形管道中，其存在于栓流与管壁之间，相对滑动的液层内。血液卡森粘度与血细胞压积，红细胞刚性及血浆粘度有关。并随上述因素的增大而增大。血液卡森屈服值与血沉无正相关性，其原因有待进一步研究。笔者建议，用卡森屈服值和卡森粘度作为定量描述卡森流体流变特性的客观指标。

The formula of Cassonian fluid isH = H + ha. The apparent viscosity ofCassonian fluid(W) conforms to the formula H=H/ H+ H. Casson viscosity(W) and yieldstress(Tc) in this f0rmula are constants that d0 notchange with ff1n within a certain range of shear rate(y)- Therefore, HWcc+H is the 0nly explanati0n ofwhy ' decreases with the increase of nY'. The in-verse ratio re1ationship must be based on the condi-tion 0f n Tc 4 O'. Otherwise, Cassonian fluid willchange into Newt0nian fluid' Casson viscosity is adynamic viscosity. It happens within the liquid 1ay-ers between plug flow and the wall of bl0od vessel.Cass0n visc0sity of blood is relevant to the ESR, theHCT and the visc0sity of plasma, and increases withthe increase of th0se three fact0rs. Casson yieldstress of blood has n0 relevance to the ESR- Thereas0n needs t0 be studied further. The writer sug-gests using Cass0n yield stress and visc0sity as theobjective indexes t0 describe the bl00d rhe010gicalcha racteristics.