The Breakup Characteristics of Liquid Sheet Formed by Like-Doublet Injectors

The atomization process of uni-element like-doublet injector includes formation of liquid sheet, fragment into ligaments, and breakup into fine drops. During the processes, breakup characteristics of the liquid sheet such as breakup length and breakup frequency affect the combustion instability as well as the efficiency of liquid rocket combustor. In this paper we proposed spray models on the breakup characteristics of the liquid sheet based on empirical data. We focused on the effects of the orifice inner flow characteristics such as cavitation phenomenon inside the sharp-edged orifice. From our experimental results, we found that the effects of turbulence inside the sharp-edged orifice are significant for the breakup of liquid sheet, and the cavitation tends to increase the turbulence strength. Since the turbulence strength of jet at the orifice exit increases as the orifice length becomes short, we also considered the effects of orifice length. Our empirical formula for the beakup length and the breakup frequency of liquid sheets formed by like-doublet injectors are believed to give some useful and actual data for designing liquid rocket combustors.