The Influence of Liquid Film Thickness on Airblast Atomization

Abstract

The influence of initial liquid film thickness on mean drop size and drop-size distribution was examined using two specially designed airblast atomizers. Both were constructed to produce a flat liquid sheet across the centerline of a two-dimensional air duct with the liquid sheet exposed on both sides to high velocity air. In one case a thin film of uniform thickness was produced by injecting the liquid through a porous plate located just upstream of the atomizing edge. The film thickness, t, was then measured by a needle contact device. In the second design the fuel entered the air stream through a thin slot whose height could be adjusted accurately to vary and control the initial film thickness. Drop sizes were measured by the well-established light-scattering technique. From analysis of the processes involved, and from correlation of the experimental data, it was found that high values of liquid viscosity and liquid flow rate result in thicker films. It was also observed that thinner liquid films produce better atomization, according to the relationship, SMD ∝ t0.38.

Measurements of droplets characteristics in a swirl-stabilized spray flame

“…Since experimental results confirm that initial liquid sheet thickness has only a minor influence on the droplet sizes produced in the spray [31], Eq. (10) indicates that, in this configuration and maintaining other parameters fixed, SMD 0 depends only on the velocity of the atomizing air.…”

Fuel injection model for Euler–Euler and Euler–Lagrange large-eddy simulations of an evaporating spray inside an aeronautical combustor

“…The liquid comes out in a hollow cone thin liquid sheet of half angle h S The spray angle depends on the design of the swirl chamber and the discharge orifice (Rizk and Lefebvre, 1985). The spray diameter distribution depends on the thickness of the film (Rizk and Lefebvre, 1980) and the liquid velocity. It also depends on the liquid properties (Rizk and Lefebvre, 1983) of the injected fuel, such as density, viscosity and surface tension.…”

Spray formation by like-doublet impinging jets in low speed cross-flows

“…It is easily imagined that the impact at the jet periphery is less intensive because a slower and thinner liquid sheet collides there. Because SMD due to laminar impinging jets is proportional to the liquid sheet thickness [24], drops in the core zone are relatively larger and faster, henceforth these larger drops are highly inertial and penetrate deep in the cross flows (Fig. 10).…”