High-fidelity simulation of air-assisted atomization with inlet gas turbulence.

Abstract

Atomization is the process for bulk liquids to disintegrate into small droplets, which is commonly seen in nature and and industrial applications. Airblast atomization is an air-assisted atomization approach and is widely used in gas turbine engines. It utilizes a high speed parallel gas stream to enhance the atomization of the bulk liquid. The velocity difference between the two fluids at the interface triggers a shear instability. The instability induces interfacial waves, which grow, roll up, and eventually break into ligaments and droplets. In order to optimize the design of airblast atomizers, it is crucial to have a comprehensive understanding of the effects of inlet gas turbulence on interfacial instability development, the primary liquid breakup mechanisms and the droplet statistics. In simulation, the turbulent velocity fluctuations are introduced in the gas inlet using a digital filtered method. A parametric study on the effect of inlet gas turbulence is studied using high-fidelity simulation. The the mass-momentum consistent volume of fluid method has been used to resolve the sharp interface. To characterize the topology evolution of the atomizing liquid jet, a novel skeletonization method has been developed.