Hydrodynamics in a horizontal stirred tank reactor

In this study, the hydrodynamics in a horizontal stirred tank reactor is in vestigated. This type of reactor is used in industry for fast polycondensat ion processes. Overall circulation, poorly mixed zones and macro-mixing tim es are determined in scale models under turbulent (Re > 10(5)) and laminar (Re < 300) conditions using planar laser induced fluorescence. For both set s of conditions, the observed overall circulation is complex and changes wh en the length-to-diameter ratio is varied. Under laminar conditions, the fl ow appears to be chaotic. The poorly mixed zones change in location, number , and life span for different length-to-diameter ratios. Dimensionless macr o-mixing times under turbulent conditions are correlated with parameter var iations and show nonlinear relationships with fill ratio, length-to-diamete r ratio, and Reynolds number. Under laminar conditions, macro-mixing times could not be determined unambiguously, but they are only 2.5 times larger t han those found under turbulent conditions.