Abstract
In an industrial washing process, using chemicals causes increase of an environmental load and processing costs. In this study, we focus on the ice jet washing technology with ice particles generated in a Venturi tube. The purpose is to improve efficiency of ice generation with a Venturi tube and to evaluate washing capability in this device. By visualization in the tube, we verified that shape of tubes was important factors to ice formation. Second, we constructed a numerical calculation system of quasi-one-dimensional stationary air single phase flow. In a converging-diverging nozzle like a Venturi tube, a supersonic flow is formed as the increase of the air flow rate and pressure and temperature are rapidly dropping in the diverging section. A similar pressure drop was observed from the pressure distribution measurement results and we indicated that a supersonic flow was formed in the tube. Furthermore, it was suggested that a reverse pressure gradient was appeared with the generation of pseudo-shock waves and cooling of water was promoted. Finally, for evaluating washing capacity of ice jet, we simulated fine particles dirt and conducted washing tests. Ice jet is verified having high washing capacity to fine particles dirt. Moreover, improvement of washing efficiency was expected by design of optimal nozzle to ice formation.
