Experimental analysis of the hydrofluidisation freezing system for small fruits and vegetables

In this work, an experimental analysis of the hydrofluidisation freezing system for small fruits or vegetables is presented. The analysis was focused on the fluid flow measurements around the spherical samples inside the hydrofluidisation chamber as well as the thermal measurements of the process. The measurements were performed on the experimental rig designed at the Institute of Thermal Technology, Gliwice, Poland. That test stand is equipped with the precise mass flow meters, thermocouples and pressure sensors. The walls of the hydrofluidisation chamber are transparent to visualise the fluid flow around the investigated sample. To capture the fluid flow, the PIV system was used. The experiments were conducted for various configurations of the orifice and sample positions. The gathered results were used for the evaluation of the heat transfer coefficient and the freezing time analysis as well as the developed CFD model validation. Finally, the recommendations for the HF system performance improvement were formulated.