Numerical Investigation of Two-Phase Flow of Non-Newtonian Fluid Discharged from a Sauce Dispenser

Abstract

Fluid dispensers are widely used in various food processing applications. The present work investigates a two-phase flow of sauce discharged from a dispenser. Preliminary simulations were conducted to study the effects of non-Newtonian properties on the resulting flow. It was found that the non-Newtonian properties of the sauce tends to distribute the flow more toward the mid-plane of the fluid field. Transient, liquid-air flow simulations were conducted to study the effects of surface tension and geometry of the dispenser on the liquid film in ambient air. The volume of fluid (VOF) method was used to track the interface between phases. Gravity was taken into account since it is comparable with the inertia force. It was found that the breakup time of the liquid film increases as the Weber number decreases and the breakup length of the liquid film increases as the Froude number increases. Practical Applications In food processing applications, various sauces are to be dispensed onto the meal tray. To ensure uniform reheating of the packaged food as well as retaining the moisture content, ideal coverage is required. When sauce leaves the dispenser, it starts to interact with the ambient air and results in a two-phase flow. Understandings of the shape of the liquid film as well as its breakup during the dispensing process are crucial to sauce dispenser design. Through numerical investigations of the dispensing process, the present work proposes optimized dispenser geometry and provides physical insights of the breakup time and the breakup length of the liquid film. Based on these findings, better design of the sauce dispenser can be achieved.