Visualization of particle/liquid movements in high viscous fluids during end-over-end rotation Original Research Article

A flow visualization study was carried out to observe the relative movement of particles in viscous fluids in containers subjected to simulated flow conditions representing thermal processing of cans under end-over-end agitation. Experiments were carried out in a pilot scale, single cage rotary retort. Transparent glass containers were used in place of the cans; Nylon particles were employed to simulate the food particles. All experiments were carried out at room temperature, with the processing vessel door held open for video taping. However, the concentration of carboxymethyl cellulose was adjusted to match those at higher temperatures so that particle mixing behavior prevailing at thermal processing conditions could be observed at room temperatures. Results showed that in low viscous fluids, the particle mixing was rapid; the particle movement was strong; the particle rotation was more frequent and the mixed fluid flow existed in the entire region of the container. On the contrary, in particulate high viscous fluids, the particle mixing was slow; the particle movement was weak; the particle rotation was restricted and the fluid flow was confined to the region along the wall of the container. The results implied that the heat transfer could easily influenced by particle to fluid relative motion and that observed differences in heat transfer in the different particulate fluid systems could be related in some way to particle motion in the can.