Experiments and simulations of surface cleaning for a gas-liquid two-phase jet

In this study, a new cleaning method for the gas-mixed water jet is proposed. The pulsation characteristics of the gas -liquid two-phase jet and the influences of parameters on the cleaning effect were analyzed by performing simulations and experiments. The results showed that the impact pressure fluctuated and was much higher than the inlet pressure. With a continuous increase in the standoff distance, the impact pressure first decreased slowly and then decreased significantly, while the diameter and depth of the crater first increased and then decreased. The optimal standoff distance for a desirable impact effect was 10 mm. With the increase in gas concentration, the impact pressure became higher for gas concentrations of less than 8%, while the impact pressure decreased for the gas concentration of more than 8%. A higher impact pressure along with a fiercer jet pulsation resulted when the flow rate became larger. Accordingly, the diameter and depth of impact crater became enlarged. The impact pressure first increased and then decreased with the increase of nozzle contraction angle. Moreover, the optimal value of such an angle was 140°. This study provides fundamental and practical guidance to further improve the application of gas-mixed water jet cleaning technology.