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This documentation is for an old version of Cantera. You can find docs for newer versions here.

Transport Properties

Cantera provides a set of ‘transport manager’ classes that manage the computation of transport properties. Every object representing a phase of matter for which transport properties are needed has a transport manager assigned to it. The transport manager has only one job: to compute the values of the transport properties of its assigned phase.

A transport manager may do things not apparent to the user in order to improve the speed of transport property evaluation. For example, it may cache intermediate results that depend only on temperature, so that if it happens to be called again at the same temperature (a common occurrence) it can skip over computing the stored temperature-dependent intermediate properties. This is why we use the term ‘manager’ rather than ‘calculator.’

In the Cantera kernel, each different transport model is implemented by a different class derived from the base class Transport. A highly simplified class structure is used in the Python interface – there is only one class.

class Cantera.Transport.Transport(xml_phase=None, phase=None, model='', loglevel=0)

Transport properties.

This class provides the Python interface to the family of transport manager classes in the Cantera C++ kernel. A transport manager has one job: to compute transport properties of a phase of matter assigned to it. The phase is represented by an object belonging to a class derived from ThermoPhase.

In the C++ kernel, a transport manager implements a single transport model, and is an instance of a subclass of the base class Transport. The structure in Python is a little different. A single class Transport represents any kernel-level transport manager. In addition, multiple kernel-kevel transport managers may be installed in one Python transport manager, although only one is active at any one time. This feature allows switching between transport models.

Create a transport property manager.

  • xml_phase – XML phase element
  • phaseThermoPhase instance representing the phase that the transport properties are for
  • model – String specifying transport model. If omitted or set to Default, the model will be read from the input file.
  • loglevel – controls the amount of diagnostic output
addTransportModel(model, loglevel=1)

Add a new transport model. Note that if model is the name of an already-installed transport model, the new transport manager will take the place of the old one, which will no longer be accessible. This method does not change the active model.


Two-dimensional array of species binary diffusion coefficients.


A short description of the active model.


Species diffusion coefficients. (m^2/s).

massFluxes(state1, state2, delta)

Mixture-averaged diffusion coefficients.

molarFluxes(state1, state2, delta)

Two-dimensional array of species multicomponent diffusion coefficients. Not implemented in all transport managers.

setParameters(type, k, params)

Set model-specific parameters.


Switch to a different transport model.


Thermal conductivity. [W/m/K].


Return a one-dimensional array of the species thermal diffusion coefficients. Not implemented in all transport models.


For internal use.


For internal use.


Viscosity [Pa-s].