Abstract
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.
