RADDIF - Mass Transport in Spherical Particles
Source Code Files, Input Files, and Result Files
Michael R. Strommen
Dept. of Environmental Sciences & Engineering
University of North Carolina at Chapel Hill
RADDIF - Mass Transport in Spherical ParticlesSource Code Files, Input Files, and Result Files
Michael R. Strommen
|
|
RADDIF is a model that simulates the dynamic partitioning of an analyte
between spherical particles and the surrounding medium (i.e., the gas or
liquid in which the
particles are
contained) by numerically simulating surface mass transfer and diffusion
in the radial direction
in the particles. The output of the model is the particle-phase
concentration in a system as a
function of time. Various parameters are input into the model including
diffusion coefficients,
mass-transfer coefficient, analyte concentration in the surrounding medium
over time,
equilibrium partition coefficient over time, particle number and size
distribution over time,
and particle mass concentration over time. Both closed and open systems
may be simulated.
For closed systems, chemical reactions may occur both in the particles and
in the surrounding
medium. The model is coupled with a parameter optimization routine to
allow optimization of
a number of parameters via multiple simulations. The model was originally designed to dynamically simulate the partitioning of organic compounds between the gas and particle phases in atmospheric aerosols (Strommen and Kamens, 1997; Strommen and Kamens, 1999). However, it may also be used to simulate microtransport of analytes in any particles of spherical geometry (or assumed spherical geometry). For example, the model may be used to simulate sorption and desorption of organic compounds by soil particles either with or without microbial reactions inside and outside the particles. The model was designed to be flexible enough to allow changes to several system characteristics via input parameters. These include particle morphology, representation of particle size distribution, determination of equilibrium partitioning coefficient, and designation of optimized parameters. This reduces the need to add to the code to model different systems of interest. The model currently consists of 18 FORTRAN source code files, two input files, and one results file. It was written in standard FORTRAN 77/90 and has been compiled and run on Windows 3.1/95/98 PCs and HP UNIX workstations.
|