Spraying ultra-viscous and non-Newtonian fluids with Filament Extension Atomization

Atomization of high-viscosity and strain-hardening fluids is difficult for existing spray generating technologies. Viscosity makes droplet breakup difficult and spraying strain-hardening fluids is not feasible due to the stability of such fluids. Filament Extension Atomization (FEA) is a novel technology to spray ultra-viscous and strain-hardening fluids. FEA involves dispensing fluid between two contacting rollers that are counter-rotating at high speeds, which turns the fluid into filaments and undergoes breakup to form a spray. In this talk, we describe the breakup process for model elastic fluids and present various products that were processed with FEA. Our current focus is on an application of FEA to spray dairy products for energy-efficient spray drying. Many dairy and food products are spray dried to produce powders, but the process is energy intensive due to the fluid concentration limit imposed by conventional spray systems. FEA-enabled spraying of high-concentration fluids reduces energy consumption by 40% and increases spray dryer output by 3.5X. We will present rheology of two dairy products – dry whey and whey protein concentrate – and explain its role in the atomization process. The atomization of high-concentration fluids achieved Dv50 < 200 µm and distribution span < 1.5, exceeding the spray quality from conventional sprayers. Finally, we demonstrate FEA at high throughput and present a vision for incorporating FEA as a next-gen spray technology in the spray drying industry.