Shear rate induced viscosity change of human blood samples and blood mimicking fluids.

ABSTRACT

Purpose: The aim of this study was to measure blood and blood mimicking fluids viscosity at different shear rates (on the interval of 0.1-5000 1/s and 0.1-10000 1/s) while taking into consideration the measuring device's capability and blood's characteristics. We also provided the measurement results of the most accurate measuring program. Methods: We measured blood samples from five donors, and four different blood mimicking fluid compositions. The measurements were done on an Anton Paar Physica MCR301 rotational rheometer with two measuring programs varying in the shear rate intervals, the number of measuring points and the measuring point durations. Results: The results confirmed the significant shear thinning and thixotropic effects of blood. Blood mimicking fluids also had these characteristics. The measured blood viscosity values are in agreement with those of the literature. Conclusions: It can be concluded that the step test program was able to give more stable results as the measured torque was over the nominal limit of 0.05 ìNm over 0.1 1/s and over the selected torque limit of 0.5 ìNm over 31.6 1/s. Blood mimicking fluid measurement results were different from that of the literature due to different measuring conditions. The sample consisting of water, glycerol and starch mimicked well blood's behaviour and viscosity values at 37 degrees Celsius.