在旋转式血液泵的研发中习惯于把血液当作牛顿流体来处理,而血液本质上是非牛顿流体。本文实验测量了0.6‰、1‰、2‰浓度的黄原胶溶液在一种离心式血泵模型内的水力特性,发现在高浓度低转速时,在相同流量下黄原胶溶液的扬程低于(或接近于)水的相应扬程,而在高转速时一定浓度的黄原胶溶液的扬程会高于水的相应扬程,最高可有7%的差值;黄原胶溶液不遵守牛顿流体相似律,一定浓度的黄原胶溶液当其雷诺数高于某一临界值后,在无量纲扬程-流量图中数据点会落在同一条曲线上,称非牛顿流体相似曲线;在高转速大流量时,非牛顿流体相似曲线位于牛顿流体相似曲线上方。
Traditionally blood, which is a non-Newtonian fluid, is treated as a Newtonian fluid in the process of R & D of rotary propeller blood pump. In present study hydrodynamics of aqueous Xanthan gum solutions in a centrifugal blood pump were measured, and concentrations of the solutions are 0.6‰, 1‰ and 2‰, respectively. It is found that when the pump operates at low rotating speed the head with the Xanthan gum solutions of high concentration is lower than that with water at same flow rate; at high rotating speeds, however, the pump will develop a higher head with the solutions than with water, and a maximum difference of 7 % is detected. The aqueous Xanthan gum solutions do not comply with the similarity law of Newtonian fluids. When the Reynolds number of a solution with a certain concentration exceeds a critical value, data points of the solution will collapse on a single curve in the head vs. capacity diagram, which is referred to as similarity curve of the non-Newtonian fluid, and each solution with a given concentration follows a unique similarity curve of its own. The non-Newtonian fluid curve is above the curve of Newtonian fluids at the range of high rotating speeds and large flow rate.