DETCHEM Fast Batch Driver

This document describes the configuration directives that are available for use with the DETCHEM Batch driver.

The batch code simulates homogeneous gas-phase and heterogeneous surface reactions in a batch reactor. The user can specify his own time-dependent temperature profiles.

This driver is significantly faster than the detchem_batch driver but contains less features. Currently, only temperature profiles are supported and the use with surface reactions is still experimental and therefore not recommended.

The code also contains an option to reduce the output file size which makes this driver especially suited for running simulations with large homogeneous gas-phase mechanisms in conjunction with a $data macro (for use in so-called "end-of-pipe" cases).

SI units are used exclusively throughout the program. Be sure to convert all values before importing data into CaRMeN. When referring to chemical species, use the correct capitalization, i.e. Ar instead of AR. Not doing so will lead to simulation errors since the species names will not be recognized.

Driver Name

This driver is available under the name detchem_batch_fast.

Output Resources

This driver outputs two tabular data resources. The primary key in each is t (time).

• mole_fractions - The species mole fractions as function of time.
• concentrations - The species concentrations as function of time.

Parameters

The following parameters are available.

# The time to integrate to.
integration_time: 2.3 # s

# An object that defines the initial conditions of the reactor.
initial:
  # The initial volume.
  volume: 0.5e-3      # m3
  # The composition of the gas at t = 0.
  # The keys represent the species and the values represent the mole fraction.
  mole_fractions:
    CH4: 0.05163
    H2O: 0.053796
    # An asterisk can be used to denote the remainder to unity. It must be enclosed in quotes!
    Ar: "*"

# The pressure in the reactor (kept constant throughout the simulation).
pressure: 0.5e5       # Pa

# The temperature in the reactor.
# If a number is given, then this temperature is taken as a constant value throughout the whole simulation.
temperature: 600      # K
# If tabular data is given, then the data is used as a temperature profile.
# The $resource macro is typically used for this.
temperature:
  $resource: ./temperature_profile.csv

# A complex object type describing the chemical model.
# Use the chemical-model loader to produce a resource with the correct structure,
# then access it using the $resource macro as shown here.
chemical_model:
  $resource: ./chemical_model


#
# Optional parameters follow below.
# The given values are the default values used when the parameter is omitted.
#

# Whether to include output at every integration step.
# Setting this to false will include only the first and last points in the output
# and hence reduce overall package size.
dense_output: true

# The ratio of catalytically active surface area and geometrical surface area.
f_cat_geo: 1          # dimensionless

# Settings pertaining to the numerical solution.
solver:
  absolute_tolerance: 1e-18
  relative_tolerance: 1e-6
  initial_integration_step_size: 1e-10
  max_integration_step_size: 10