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Numerical investigation of multiphase flow of non-Newtonian fluids in a sauce dispensing system
In food processing applications, a dispensing system is used to dispense sauces onto the meal tray. Food particles such as sliced vegetables and meats are present in the sauces. It is desired that the sauces and food particles should spread uniformly on a meal tray for even reheating. To ensure full coverage, it is desired that the shape of the liquid film matches that of the meal tray. Transient, liquid-air flow simulations are conducted to study the effects of surface tension and geometry of the dispenser on the liquid film in ambient air. It is found that the non-Newtonian properties cause the fluid to flow toward the mid-plane of the flow field. In addition, 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. The Eulerian-Lagrangian approach with one-way coupling is adopted to investigate the fluid-particle flow of sauces and food particles. To account for the large size of the food particles, subroutines are developed to simulate the particle-wall collision and calculate the pressure gradient force applied on the particle. The standard deviation of the particle residence time is important for even coverage of the food particles. It is found that the particle-wall collision reduces the average and standard deviation of particle residence time. The standard deviation increases as the Stokes number increases. For a constant Stokes number, as the particle size increases, the standard deviation first increases and then decreases. Furthermore, it is found that the inclusion of the pressure gradient force reduces the average and standard deviation of particle residence time. As the particle volume fraction increases, a two-way coupling approach is needed. An effort towards this end is made by implementing the Immersed Boundary Method in ANSYS Fluent. For the flow across a circular cylinder with a constant Reynolds number, the drag coefficient increases as the power-law index increases. The flow of a single particle in non-Newtonian fluids is simulated. The two-way coupling approach shows the effects of lift force on the particle motion.
Fluid mechanics|Food Science|Mechanical engineering
Chen, Ruiyan, "Numerical investigation of multiphase flow of non-Newtonian fluids in a sauce dispensing system" (2017). ETD collection for University of Nebraska-Lincoln. AAI10681929.