Rheological models for temperature and concentration dependencies of coal water slurry

Rheological properties of coal water slurry (CWS) with different concentrations (45.77, 50.78, 52.13, 55.56, 57.67, and 61.06 wt%) were investigated by rotational rheometer at different temperatures (20–60°C), and shear rate with integral magnitude logarithmically increased from 1 to 200 s⁻¹. The results show that the CWS is a pseudoplastic fluid, whose rheological characteristic follows Bingham model well. Both the yield stress and Bingham plastic viscosity increase with increasing concentration and usually decrease with the temperature. The concentration of CWS has a positive correlation with the apparent viscosity, and the relationship is described by power law model. The apparent viscosity decreases first and then increases with the temperature, there is a critical temperature. The Guzman–Andrade equation is adopted to exhibit the effect of temperature on apparent viscosity. The rheological model coupled with shear rate, concentration, and temperature is obtained, and the adjusted coefficient of determination is 0.954 that illustrates there is a goodness of fit. The results of this study put forward a new method to obtain empirical model of non-Newtonian fluid.