Species Data Page

Here you enter for each species the values of its physical parameters the simulator requires to perform its calculation. The page displays a table of the species properties that appears similar to this:

Required Parameters

The specific parameters that are required depend on the type of reaction scheme and the simulation conditions you have selected on the Reaction Conditions Page.

  • For a single reactor scheme, you will always specify here the initial starting concentrations/amounts of all reactants. When a concentration value is entered, the number of particles required to represent this concentration is displayed as an aid in setup.

    With compartmental and three-dimensional reaction schemes, you specify the species concentrations in each individual compartment using the Compartment Editor Dialog.

  • If temperature is variable, you must specify the thermochemical coefficients for every species in the system. Temperature changes are calculated iteratively from the change in the temperature-dependent enthalpy and heat capacity of the system as the reaction progresses according to the expression:

    ΔT  =  2 [ ΔH(T1) - ΔH(T2) ]
    ΔCp (T1) + ΔC (T2)

    and the change in heat capacity with temperature for each species is :

    ΔCp (T)  = b + cT + dT2 (2)

    where ΔH is the total enthalpy and ΔCp is the heat capacity at constant pressure, summed over all the species in the system.

    The expression for the change in enthalpy with temperature for each species is:

    ΔHf (T)  = ΔH0 + a + bT + cT2 + dT3 (3)

    where ΔH0 is the enthalpy in energy units, and the coefficients a, b, c and d are the temperature-dependent heat capacity in (energy units)/mol-degn, where energy can be in joules or kcals. In precise calculations, ΔH0 must be the enthalpy of formation at 0 K. If constant heat capacity is used, Cp=b and the coefficients a, c and d are explicitly set equal to zero.

    For an example, see the example reaction scheme the Thermal decomposition of ozone (I).

  • If volume is variable, the molar density (in moles/unit volume) must be specified for each species. This allows Kinetiscope to calculate the system volume during the simulation.

    For single reactor reaction schemes only, you must also specify the physical state of each species. Although a mixture of phases is allowed to be generated during a single reactor simulation, only one phase may be present initially. Only the volume of that phase is tracked.

    For three-dimensional reaction schemes and compartmental reaction schemes, explicit specification of phase is not needed. Each compartment is a single phase so phase changes are accounted for in the configuration of the reaction scheme.

    For demonstrations on how to construct multiphase reactions, see the series of Example Simulations Thin Film Curing (I), Thin Film Curing (II), and Thin Film Curing (III).

Entering Species Data

To enter a numeric value into a cell of the species data table:

  1. Click or double-click on the cell you wish to edit.
  2. Type the new value.
  3. Press the Enter key or move the cursor to another cell to save your edited value.
To change the physical state setting in a single reactor reaction scheme:
  1. Double-click on the cell you wish to edit.
  2. Select a value from the list of states that appears in the drop-down list box.

Renaming a Species

To change the name of a species throughout the reaction scheme:

  1. Right-click on the species name you wish to change and select the Rename... menu item.
  2. Type the new value into the entry field of the dialog that appears. The text you enter must be a valid species name and the new name must not already be in use in the reaction scheme.
  3. Press the Enter key or click the OK button to close the dialog and rename that species with your edited value everywhere it is used in the reaction scheme.