Abstract
Heat transfer to canned particulate-laden Newtonian high-viscous fluids (Nylon particles suspended in aqueous glycerin solution [40, 60, 80, 90 and 100%, v/v] and motor oil [85W140]) during end-over-end rotation was studied in a pilot-scale, full water-immersion single-cage rotary retort. Computations of conventional fluid-to-particle heat transfer coefficient (hfp) and overall heat transfer coefficient (U) were successful with multiple particles for an entire range of viscosity, but the predicted particle lethality was underestimated. With a single particle in the can, hfp and U calculations were successful only for low-viscosity fluids (40 and 60% glycerin solutions), but again resulted in underestimation of particle lethality. Apparent heat transfer coefficients (hap) between retort and particle surface and apparent overall heat transfer coefficient (Ua) were also evaluated, and this methodology worked well for all cases. Further, the particle lethality predicted using hap better matched the measured values. With a single particle in the can, the associated hap was significantly (P 0.05) influenced by rotation speed, retort temperature, liquid viscosity, particle material and can size. Ua was significantly (P 0.05) influenced by rotation speed and liquid viscosity. The effects of headspace, radius of rotation and particle size were not significant (P > 0.05) on hap and Ua values.
Published Version
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