Constant Pressure Reactor#
For this reactor model, the pressure is held constant and the energy equation is defined
in terms of the total enthalpy. This model is implemented by the C++ class
ConstPressureReactor and available in Python as the
ConstPressureReactor
class. A constant pressure reactor is defined by the
state variables:
, the mass of the reactor’s contents (in kg) , the total enthalpy of the reactor’s contents (in J) , the mass fractions for each species (dimensionless)
Equations 1-3 below are the governing equations for a constant pressure reactor.
Mass Conservation#
The total mass of the reactor’s contents changes as a result of flow through the reactor’s inlets and outlets, and production of homogeneous phase species on surfaces:
Where the subscripts in and out refer to the sum of the superscripted property over all inlets and outlets respectively. A dot above a variable signifies a time derivative.
Species Equations#
The rate at which species
The rate of change in the mass of each species is:
Expanding the derivative on the left hand side and substituting the equation for
Energy Equation#
Writing the first law for an open system gives:
where positive
Differentiating the definition of the total enthalpy,
Noting that