Investigation on droplets' turbulence characteristics of hollow-cone spray in far downstream region

The flowfield of a spray is usually of the two-phase jet type with polydispersed size spectrum. For a typical jet flow, the proportionality among the three square mean fluctuating velocity components follows (predominant flow direction): (radial direction): (azimuthal direction) =1:1/2 :1/2 as the flow reaches the condition of self-conservation. However, the above description is valid for the single-phase flow. It is interested to known whether or not this proportionality is applicable to the both (carrier and dispersed) phases in sprays, because this information will be helpful in determination of the turbulent kinetic energy for either phase once the three-velocity-component experimental data are unavailable. A well-defined hollow-cone spray, which is inherited weak swirling flow in the initial flow region due to the interior configuration of the pressured type atomizer, is used as the test problem. It is shown that the turbulence characteristics of the small particles approach the self-preservation condition in the far downstream regions, whereas those of the large particles do not exhibit this behavior.