Analysis and Simulation of a Powders Dissolution System based on Hydrodynamic Controlled Cavitation.

Food powder dissolution is a process frequently adopted for beverages production. Among the different powder dissolution methods tested in literature, Hydrodynamics Controlled Cavitation is one of the most promising, giving the same effect of ultrasounds, with a lower overall cost. With the purpose to try this technology, specific equipment has been designed and tested. The designed system is based on the Venturi effect, able to generate a hydrodynamic controlled cavitation in the diverging section. Given the system, the main aim of the present work is to develop a CFD simulation of this hydrodynamic cavitation system for food powders dissolution and perform experimental tests in order to validate it. Simulation is able to verify the presence of cavitation, calculate the cavitation number and, finally, define how the cavitation effect changes with the injection of air. Multicomponent fluid flow setting has been used for the simulation, with the addition of a cavitation module implemented in Ansys CFD Software version 14.5. Simulations and experimental tests are performed considering a concentration of powders in a range of 1-3% respect to the water. Selected powders are off-white blend of food grade stabilizers and food grade CMC that are particularly useful for thickening and stabilizing of beverages. Results show the cavitation’s presence in the diverging section of the Venturi system and a good agreement between simulation analysis and experimental results in fluid dynamic parameters (relatives to pressure, velocity and volume fraction of powders). Finally a correlation between the dissolution level and the cavitation effect has been obtained showing how the proposed multicomponent CFD model can be useful to define the optimum process condition.