NGDE: Software for Solution of Nucleation, Surface Growth and
Coagulation Problems
A. Prakash, A. P. Bapat, and M. R. Zachariah*
Departments of Mechanical Engineering and
Chemistry
ABSTRACT
A simple numerical method to solve the
General Dynamic Equation (GDE) has been described and the software made
available. The model solution described
is suitable for problems involving gas to particle conversion due to supersaturation,
coagulation, and surface growth of particles via evaporation/condensation of
monomers. The model is based on simplifying the sectional approach to
discretizing the particle size distribution with a nodal form. The GDE
developed here is an extension of the coagulation equation solution method
developed by Kari Lehtinen (Lehtinen and Zachariah, 2001) wherein particles
exist only at nodes, as opposed to continuous bins in the sectional method. The
results have been tested by comparison where simple analytical solutions are
available, and are shown to be in excellent agreement. By example we apply the
model to the formation and growth of Aluminum particles. The important features
of the model is that it is simple to comprehend, the software which we call
Nodal-GDE Solver (NGDE) is relatively compact, and the code is well documented
internally, so that users may apply it to their specific needs or make
modifications as required.
The software is being distributed as freeware, with the
request and expectation that attribution be provided for work performed using
the code.
NGDE CODE
The numerical algorithm has been
implemented in C. The example problem is specific for a growth of aluminum
aerosol by the evaporation-condensation method, however, the software is
designed to allow the user to apply it to other systems where property data
such as saturation vapor pressures and surface tension are known.
The program code performs four main
types of calculations
1.)
pure
coagulation,
2.)
coupled
nucleation and coagulation,
3.)
pure
surface growth
4.)
unified
GDE containing all of the above.
The program execution consists of the
user inputting to the input file the necessary data about the aerosol material
properties and the process conditions. The output can be either viewed on the
console or directed to a file for storage.
The source code for the program has a modular structure.
Each section of the code is independent of other sections. The source is well
commented, and a list of variable names, and their units are documented within
the code to allow the user to make customized changes.
The NGDE package provided, consists of the source code in C, an instruction file readme.txt, and the sample input files for the example problem discussed in the AS&T paper.
DOWN
LOAD THESE FILES
NGDE Software (written in C language)
DOWNLOAD ALL THREE INPUTS
Download in ZIP format
(contains executable file for Windows OS)
The software is
being distributed as freeware, with the request and expectation that
attribution be provided for work performed using the code.