Tomography, an efficient nonintrusive technique, was employed to visualize the flow in continuous-flow mixing and to measure the cavern volume (V-c) in batch mixing. This study has demonstrated an efficient method for flow visualization in the continuous-flow mixing of opaque fluids using two-dimensional (2-D) and 3-D tomograms. The main objective of this study was to explore the effects of four inlet-outlet configurations, fluid rheology (0.5-1.5% xanthan gum concentration), high-velocity jet (0.317-1.660 m s(-1)), and feed flow rate (5.3 x 10(-5)-2.36 x 10(-4) m(3) s(-1)) on the deformation of the cavern. Dynamic tests were also performed to estimate the fully mixed volume (V-fully mixed) for the RT, A310, and 3AM impellers in a continuous-flow mixing system, and it was found that V-fully mixed was greater than V-c. Incorporating the findings of this study into the design criteria will minimize the extent of nonideal flows in the continuous-flow mixing of complex fluids and eventually improve the quality of end-products. (c) 2013 American Institute of Chemical Engineers AIChE J, 60: 315-331, 2014