Large Eddy Simulation of High-Viscosity Spray Injection Using Volume-of-Fluid Method

Efficient atomization is crucial for combustion efficiency in aircraft gas turbines. However, high viscosities of potential alternative fuel candidates significantly hinder effective spray breakup. To understand the primary atomization behavior of such fluids, this study employs a geometric volume-of-fluid method coupled with large eddy simulation, a compressible-gas and incompressible-liquid formulations, on an octree-based adaptive meshing to resolve the high-viscosity spray in an air-blast injector. The approach captures interface dynamics from coherent liquid cores to ligaments and droplets and is assessed against companion measurements. The simulation show that early shear-driven instabilities are damped by viscosity, causing breakup to proceed through long, slowly stretching ligaments and thereby prolonging the primary-breakup stage. The predicted volume-based droplet size distribution agrees in trend with experiments. The framework establishes a validated path for predictive modeling and supports atomizer design for alternative fuels in combustors.