Discharge of Newtonian and Non-Newtonian Liquids from Tanks

Results of experiments concerning gravitational discharge of Newtonian and non-Newtonian shear thinning liquids from a tank have been presented. Survey has been carried out for Newtonian liquids of very high viscosity up to 26.2 Pa s and for non-Newtonian liquids with rheological parameters: k = 0.11–15.1 Pa sn and n = 0.457–0.771. Discharge orifices had the diameters 5, 8, 12.5 and 17 mm, and the ratio of orifice length to diameter L/d was 0, 0.35, 0.5, 0.75, 1 and 3. Equations describing discharge coefficient as a function of the Reynolds number and orifice geometry have been proposed. In the case of Newtonian liquid discharge the proposed correlation equation described experimental data with mean error equal to 7.1%, and in the case of non-Newtonian liquid discharge the mean error was equal to 5.7%.