Atomization of non-Newtonian liquids is widely used for spray combustion, spray drying, spray cooling, and so on. The purpose of this study is to predict the discharge coefficient (“C”) of pressure nozzles for non-Newtonian liquids based on the estimation of the apparent viscosity at the injection. Detergent slurry is a non-Newtonian liquid with pseudo-plasticity, which is approximated with the generalized-Bingham model. It is estimated that the apparent viscosity of slurry at the injection is not so high because of its high shear rates (γ) in the swirl chamber. The shear rate “γ” at the injection is evaluated as the inlet velocity (u) to the swirl chamber divided by the radius of vortex in the swirl chamber (ri-ro). According to this assumption, the apparent viscosity of the detergent slurry is approximately 0.1 to 0.3 Pa·s. It is found that the correation between “C” and nozzle parameter “Δm” for the detergent slurry are compatible with those for PEG solution, which is a typical Newtonian liquids, at the viscosity of 0.1 to 0.3 Pa·s. It is considered that the assumption of the apparent viscosity at injection is useful for the prediction of “C” for non-Newtonian liquids.
Effects of the amount of iron based catalysts and reaction temperatures on the liquefaction of Taiheiyo coal was investigated with respect to hydrogen transfer to the products. The catalysts used were FeS2 and a sulfate promoted iron oxide (Fe-sulfate). Amounts of the catalysts were varied in the range of 0.4% to 19% to coal and reaction temperatures were changed between 648K and 723K. Conversions of coal was independent upon kinds of catalyst. Futhermore, the reaction temperature of around 698K was found to be better for both catalysts. On the basis of the hydrogen transfer to the products, it was found that the reaction products obtained at a lower or a higher temperature contained higher aliphatic fraction and higher aromatic fractions, respectively. Another findings were observed in the results on effect of amounts of catalysts. The FeS2 catalyst required more than 8 wt% to coal in order to promote the liquefaction reaction effectively, but the amount of Fe-sulfate catalyst was much smaller. Optimum amount of the Fe-sulfate catalyst was found to be about 2% to coal with respect to effective liquefaction reaction of coal.