A novel method to characterize morphological dynamics and determine flashing jet regimes

Spray cone angle (θ) and width (H) have been widely used to characterize morphology of jets. However, to a flashing jet, their capabilities are restrained by two flaws: (a) they are variable as a function of axial distance (θ (H)=f(x)), leading to nonunified θ or H at different axial locations, and (b) fail to precisely capture key characteristics of nonlinear boundary of expansion zone, resulting in their disability to determine the flashing jet regimes. In this work, a power function |y|=kx^0.5, in which x and y are axial and radical directions respectively, characterizing the nonlinear boundary of expansion zone of flashing jet is proposed. A variety of experiments are conducted to validate the proposed method. Experimental results demonstrate that the graphical parameter k unifies a cluster of spray angles (θ=f(x))), and furthermore, owns a good capability to characterize morphological dynamics of flashing jet. These merits allow k to determine the flashing jet regimes. In this work, k<1, 1<k<5, and k>5 are the determining criteria for the external, internal transition, and full flashing jet regimes, respectively.