Prediction of Cloud Height for Solid Suspensions in Stirred Tanks

Solid particle distribution of moderately concentrated suspensions in a pilot plant stirred vessel

“…This phenomenon has frequently been observed in the past and was firstly discussed by Musil [21]. Further papers [4,[22][23][24][25][26][27][28][29][30][31] describe the effects on this phenomenon of particle size and concentration, impeller type and speed, impeller off-bottom clearance, stirrer and vessel size, mixing time and physical properties of the system. Several references are indirect, focused on the study of various suspension system parameters, e.g.…”

Experimental measurement and computational fluid dynamics simulation of mixing in a stirred tank: a review

“…Simulation methods have been developed to link the typical experimental and theoretical approaches for investigating mixing features, such as wall jet, to the CFD simulation methods. 15 The experimental methods for measuring mixing time have been successfully adopted in CFD simulation. 5,7,40 Previously, the required computational power could not allow simulations with very fine grids.…”

“…This jet is an important feature in a mixing tank and has attracted attention, especially with regards to solid-liquid mixing. 15,16 The upward jet is influenced by baffles and it decays with an increase in tank height.…”

Models and Applications for Simulating Turbulent Solid–Liquid Suspensions in Stirred Tanks

“…For solids loadings greater than 10 weight percent in a stirred tank, a clear solid-liquid interface usually exists in the upper part of the vessel, and the height of this interface is known as the cloud height (Bittorf and Kresta, 2003). The formation of a clear liquid layer is caused by the axial velocity of the continuous phase being lower than the particle settling velocity (Bittorf and Kresta, 2003;Micale et al, 2004).…”

“…The formation of a clear liquid layer is caused by the axial velocity of the continuous phase being lower than the particle settling velocity (Bittorf and Kresta, 2003;Micale et al, 2004). Micale et al (2004) compared the empirically determined cloud height with that derived from E-E simulations.…”