Tutorials Manual

Chapter 2: Combustion in Gas-phase Processes
Tutorials Manual
Figure 2-58 A schematic of the JSR/PFR reactor configuration used by Marr 23
2.7.1.1 Problem Setup
The CHEMKIN project file for this tutorial is named
reactor_network__soot_JSRPFR.ckprj and is located in the samples41 directory.
The reaction mechanisms for ethylene/air combustion and soot formation and growth
are described in Section 2.8.
The JSR/PFR experiment shown in Figure 2-58 can be modeled by one PSR and two
PFR’s in series. The first PSR is for the upstream (or flame zone) JSR, the following
PFR is to model the transition piece between JSR and PFR in the experimental setup,
and the last PFR is for the postflame PFR where measurement was performed. The
main purpose of the transition PFR is to allow the JSR exhaust to cool down from
1630K to 1620K before entering the test section. The diagram view of this threereactor
network is given in Figure 2-59. Since the Particle Tracking Module is
activated by special keywords in surface reaction mechanism, all soot simulations will
need both gas phase and surface chemistry input files. Once the chemistry files have
been pre-processed, the Dispersed Phase tab will appear in the Reactor Physical
Properties panel as shown in Figure 2-60. Most parameters for the Particle Tracking
Module can be assigned in this Dispersed Phase tab. Initial conditions of the particle
size moments can also be specified here. The initial size moments can be constructed
from particle number density alone. Additional particle size information such as
particle mass density or particle volume fraction can also be specified. Because the
dispersed phase does not exist on the reactor wall, the surface area fraction of the
particle material must be set to zero in the Material-specific Data tab (see
Figure 2-61). Here, we set Carbon to 0.0 and Wall to 1.0. (Parameters for all materials
can be specified on the Reactor Physical Properties tab.)
RD0411-C20-000-001 79 © 2007 Reaction Design