Code Manual for CONTAIN 2.0 - Federation of American Scientists

(7-3)
where d(&(t)/dt is the time rate of
———
change of aerosol mass of component k per unit volume in section
1 at time t and the coefficients (~ ,G,S, and ~) are defined below. This equation describes the
evolution of the aerosol size and composition distributions within one computational cell. Each cell
has its own particle size and composition distributions, and the aerosols are carried from one cell to
the next by intercell gas flow, as discussed in Section 7.8, but the cell dependence and flow terms
are not explicitly represented in Equation (7-3). It should be noted that the ~ condensation terms
in the above equation are written for condensing conditions within the fixed-grid option discussed
in Section 7.2.2 A similar expression is used for evaporating conditions.
The coefficients in Equation (7-3) correspond to the following mechanisms:
Coefficient Represents
F
Agglomeration, m3/s-kg,
G Vapor condensation,s- 1,
s Sources, kg/m3-s,
% Deposition, kg/m3-s.
The six types of agglomeration coefficients in Equation (7-3) represent the following processes:
‘a~ij,$
‘b~ij,t
‘iPi,l
addition of component k in section ~,through a particle in section j coagulating with
a particle in section i to form a particle in section !. In this case, the component k
comes from section j.
addition of component k in section 1,through a particle in section i coagulating with
a particle in section j to form a particle in section I?.In this case, the component k
comes from section i.
removal of component k in section 1,through a particle in section i coagulating with
a particle in section !, and forming a particle larger than those in 1.
Rev O 78 6/30/97