Nucleation - SPL-ethz/CAT GitHub Wiki
The process of creating a new solid phase from a supersaturated homogeneous mother phase is called nucleation and is central to all types of crystallization.[1]
On this page, general hints are given about the loaded values and functions in this demo case. If you want an overview and explanation of the resulting plots, click here.
The first field specifies the initial particle size distribution. Clicking on "Edit" opens a window which shows a preview of the chosen distribution. Moreover, the underlying grid can be specified by setting the number of grid points and the distance of the so called pivot elements. In the second field the initial seed mass is set. The third field asks for the initial mass of the continuous medium, which gives the total mass of solvent and antisolvent.
In the last field the initial concentration is set. Note that the concentration is defined as
and therefore it is dimensionless.
In the first field the temperature profile is set. The default profile is a linearly decreasing profile. In the second field the profile for the antisolvent is defined. However, in this case, the antisolvent is kept constant and therefore the slope is zero. The profiles will be plotted automatically by solving the system.
Note that the solubility function is an anonymous function with up to two variables. The two variables are temperature (T) and antisolvent mass fraction (xm). However, the default function loaded in this case is a function of temperature only.
The shape factor for a cube is 1 (default). For a sphere it would be Pi/6 (where the characteristic length is the diameter).
The growth rate is defined according to formula
where the first bracket is a logical expression (growth only if supersaturated), k is a constant and the last bracket denotes the driving force.
This time, the nucleation rate is non-zero. The nucleation rate is a function of supersaturation, temperature, moments of the distribution and time t. It is defined as an anonymous function.
> [1] Davey, R., & Garside, J. (2000). From molecules to crystallizers. Oxford University Press.