INVESTIGATION OF GAS-DISSOLVING EFFECT ON THE SPRAY-FORMATION OF A STEADY-JET

This paper presents a further investigation of the effect of gas-dissolving on the atomization characteristics of a steady-jet. On the basis of the previous feasibility studies, a parametric study was developed, by varying the dissolved-gas concentration and the nozzle configuration parameter. A detailed measurement of dissolved-gas concentration within a container shows that a gas-blasting method realizes completely uniform concentration distribution but the gas-pressing method produces large distribution under some condition varying from zero to its saturated value. When the dissolved-gas concentration is relatively low, it has an effect of atomization suppression. When the concentration is relatively large, the dissolved-gas has an effect of promotion which is caused by a characteristic mode of atomization. Thus, there is a critical concentration of the effect. These effects tend to be more intense with the increase in the nozzle L/D ratio. Therefore it can be said that the sensitivity of the dissolved-gas effect is increased with increasing the L/D ratio, which may be related to the residence time within the nozzle. The kind of dissolved-gas is also suggested to be important for the effect. Even when the atomization is suppressed by the gas-dissolving, the spray includes the atomization improved part in its periphery. This means that the spray has a dual-construction and the promotion of atomization starts to occur from its periphery.