Tracer experimental techniques for CFD model verification and validation in sugar crystallizer

In the framework of the CRP improvement of the experimental design for RTD tests at a pilot crystallizer was performed. A new approach for RTD studies in non-Newtonian fluids for flow patterns characterization at the pilot crystallizer was carried out. Batch mixing process was tested and the homogenization time for massecuite fluid close to seven hours proved that the crystallizers with relative low residence time that the Cuban sugar industry is trying to develop will achieve low exhaustion efficiency with significant sugar losses. The flow simulation was carried out by CFD Flotran in ANSYS 5.4 package. The possibility of RTD prediction on the basis of numerical solution of transport equations for fluid dynamics in a more simplified geometry of the crystallizer and molasses as fluid using transient analysis of temperature pulse spreading is discussed. Finally,
taking in account that in complex flow structure, the most general Stimulus Response Method (SRM) based in point source response (PSR) is more suitable for CFD verification than the ambiguous, in some cases, RTD function, the design and preparation of a multipurpose relative long live 99Mo/99mTc point source device has been developed and special PC-program has been prepared for the interpolation of detector responses function.