Code Manual for CONTAIN 2.0 - Federation of American Scientists

10.0 HEAT AND MASS TRANSFER MODELS
Heat and mass transfer processes are modeled at a number of interfaces in the CONTAJN code. The
present chapter gives a general discussion of the heat and mass transfer modeling at such interfaces,
in addition to a discussion of heat sink modeling and associated topics. Exceptions to this general
treatment are noted in the discussion. Two types of heat sinks, heat transfer structures and lower cell
layers, are discussed. The topics associated with heat sink modeling include heat sink characteristics
and boundary conditions, heat conduction modeling, and the treatment of concrete outgassing. A
discussion of the modeling available with respect to lower cell layers outside of these areas is given
in Chapter 5.
The present chapter is organized by process type. Natural convection and forced convection heat
transfer are discussed in Section 10.1, along with boundary layer properties and other quantities
entering the expressions for convective heat transfer. Mass transfer processes are discussed in
Section 10.2, along with quantities entering the expressions for mass transfer. Processes discussed
in that section include condensate fdm flow on surfaces and condensation mass transfer. Radiative
heat transfer is discussed in Section 10.3; boiling heat transfer is discussed in Section 10.4. The
modeling of heat sinks and the associated topics mentioned above are discussed in Section 10.5. Key
elements of the heat and mass transfer models are illustrated in Figure 10-1.
Table 10-1 indicates the various code interfaces addressed by the present chapter, as well as the
processes considered at each interface. The pool-structure interface listed in this table was
implemented in CONTAIN 1.2, in conjunction with the pool tracking modifications, which allow
the pool to be treated as a bulk fluid on the same footing as the gas. One consequence of these
modifications is that heat transfer structures can now be submerged in the pool, as discussed in more
detail in Section 10.1.1.4. Note that the distinction made in this table with regard to whether a
process is simply modeled or modeled and coupled to the interface temperature calculation refers
to the role of the process in determining the interface conditions. This distinction is explained in
more detail in Section 10.6, in which the coupling between the heat and mass transfer processes is
discussed.
Table 10-1
Heat and Mass Transfer Processes
Considered at Various CONTAIN Interfaces*
Interface
Conv.
HT
Cond. Rad.
HT
Boiling
HT
Aerosol Film
Inflow
Gas-Structure c c c - c c
Gas-Pool c c c - M M
Gas-Lower Cell c c c - M -
Pool-Structure c - - - - -
Pool-Lower Cell c - - M -
Gas-Engineered System c c - - M -
●HT=heattransfe~MT=masstransfe~C=modeledandcoupledtointerfacetemperaturecalculation;M=modeled
butnotcoupled
Rev O 1o 1 6/30/97