# Test Case for Constant Decontamination Model

## Description

This 0D test case is designed to assess the scrubbing decontamination process
using the constant decontamination model.

In the computational domain, both the gas and liquid are multicomponent phases.
The gas phase consists of particle and air species, while the liquid phase
consists of particle and water species. The initial volume fractions of both the
gas and liquid phases are set to $0.5$.

Initially, the mass fraction of air in the gas phase is $0.9$, and that of the
particle is $0.1$. The model describes the mass transfer of the particle species
from the gas phase to the liquid phase. Therefore, the initial particle mass per
unit volume is $Y_G^P \alpha_G \rho_G = 0.0658$ [kg/m$^3$].

To compare with an analytical solution, the constant mass transfer rate is set
to $0.01316$ [kg m$^{-3}$ s$^{-1}$], such that all particles are completely
transferred to the liquid phase after 5 seconds. Once the particle mass in the
gas phase vanishes, the mass transfer rate becomes zero.

## Technical Information

- 0D
- $1$ cell
- The mass transfer rate is $0.01316$ kg m$^{-3}$ s$^{-1}$
- $d_B = 5$ mm
- Multicomponent phases are used for the gas (of air and particle species) and
  the liquid (of particle and water species)

## Post processing

- The ratio of the current to the initial particle volume fraction in the
  gas phase, aka retention ratio, is observed over time
- The particle mass per unit volume in the gas phase is compared with the
  analytical solution, showing that it approaches zero around $t=5$ s.

## Keywords

0D, multiphase, three-phase, multicomponent, gas, liquid, isothermal,
incompressible, scrubbing decontamination, pool scrubbing[^1], phase transfer

## Literature

[^1]: Liao, Y., Li, J., & Lucas, D. (2022). Investigation on pool-scrubbing
      hydrodynamics with VOF interface-capturing method. *Nuclear Engineering
      and Design*, 390, 111713.
