Tools · Fluids & Thermodynamics

Cantera

Chemical equilibrium, reactor and ignition simulations, laminar flames, transport properties, and reaction path analysis with Cantera.

Updated October 1, 2026

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Cantera solves chemical kinetics, thermodynamics, and transport problems for gas mixtures. One job type covers five kinds of problem, chosen with mode:

`mode`	What it computes
`equilibrium`	The equilibrium state and composition under a constraint (`TP`, `HP`, `SP`, `SV`, `UV`, `TV`), optionally from an equivalence ratio with fuel and oxidizer
`reactor`	A constant-volume or constant-pressure reactor over time: species and temperature histories and ignition delay, with optional wall heat loss
`flame`	A freely propagating, one-dimensional premixed flame: species and temperature profiles and flame speed, with a choice of transport model, Soret diffusion, and grid refinement
`transport`	Viscosity, thermal conductivity, and diffusion coefficients over a temperature range, with optional binary diffusion coefficients
`path_analysis`	Element fluxes and rates of production, with a reaction path diagram

It runs on CPU.

Inputs

The mechanism: one of the built-in mechanisms with mechanism_id (gri30 for natural gas combustion, h2o2 for hydrogen), or your own as an uploaded file or an artifact in Cantera YAML (CHEMKIN, CTI, and XML mechanisms also chain in from other tools).
The problem: a structured problem_spec whose fields depend on the mode (the allowed fields are checked), or a full Cantera YAML problem in cantera_yaml, or a problem object.

Each mode fills its own table: reactor_history, flame_profile, transport_table, species, or rate_of_production (CSV), alongside the full output zip, which for path_analysis includes the path diagram.

Chaining

Mechanisms from RMG Mechanism Generator, Mechanism Reduction, and NASA / Cantera Species Builder can feed straight into a Cantera step in a workflow.

Not covered

Well-stirred and plug-flow reactors, other flame configurations, surface chemistry, electrochemistry, and sensitivity analysis aren't available yet. For real-fluid properties (steam, refrigerants) use CoolProp; for vapor–liquid equilibrium use VLE / Flash.

Run it from the API

Submit with Submit a job and the job_type below. Price it first with Estimate job reservation cost: submitting reserves that amount from your wallet, and the charge settles at the actual runtime.

Cantera `cantera`

Job type: cantera
Hardware: cpu (default)
Typical runtime: 2 h on CPU

Payload

Provide exactly one of: mechanism, mechanism_id.

Provide exactly one of: cantera_yaml, problem, problem_spec.

Payload fields
Field	Type	Description
`mode`required	`string`	One of: `"equilibrium", "reactor", "flame", "transport", "path_analysis"`
`mechanism`	`file_object`
mechanism.`name`	`string`	Limits: `min length 1`
mechanism.`filename`	`string`	Limits: `min length 1`
mechanism.`content_b64`	`string`	Limits: `min length 1`
mechanism.`content`	`any`
mechanism.`bytes`	`any`
`mechanism_id`	`string`	One of: `"gri30", "h2o2"`
`cantera_yaml`	`string`	Limits: `min length 1`
`problem`	`file_object`
problem.`name`	`string`	Limits: `min length 1`
problem.`filename`	`string`	Limits: `min length 1`
problem.`content_b64`	`string`	Limits: `min length 1`
problem.`content`	`any`
problem.`bytes`	`any`
`problem_spec`	`object`
problem_spec.`temperature`	`number`
problem_spec.`pressure`	`number`
problem_spec.`composition`	`string`	Limits: `min length 1`
problem_spec.`time_end`	`number`	Limits: `> 0`
problem_spec.`fuel_composition`	`string`	Limits: `min length 1`
problem_spec.`oxidizer_composition`	`string`	Limits: `min length 1`
problem_spec.`equilibrate_at`	`string`	One of: `"TP", "HP", "SP", "SV", "UV", "TV"`
problem_spec.`reactor_type`	`string`	One of: `"IdealGasReactor", "IdealGasConstPressureReactor", "IdealGasMoleReactor", "IdealGasConstPressureMoleReactor"`
problem_spec.`max_steps`	`integer`	Limits: `> 0`
problem_spec.`width`	`number`	Limits: `> 0`
problem_spec.`equivalence_ratio`	`number`	Limits: `> 0`
problem_spec.`species_of_interest[]`	`string[]`
problem_spec.`elements[]`	`string[]`	One of: `"C", "H", "O", "N", "S", "Ar"`
problem_spec.`wall_area`	`number`	Limits: `> 0`
problem_spec.`wall_u`	`number`	Limits: `> 0`
problem_spec.`env_temperature`	`number`	Limits: `≥ 0`
problem_spec.`transport_model`	`string`	One of: `"mixture-averaged", "multicomponent"`
problem_spec.`soret_enabled`	`boolean`
problem_spec.`energy_enabled`	`boolean`
problem_spec.`refine_ratio`	`number`	Limits: `> 0`
problem_spec.`refine_slope`	`number`	Limits: `> 0`
problem_spec.`refine_curve`	`number`	Limits: `> 0`
problem_spec.`temperature_max`	`number`
problem_spec.`n_temperature_points`	`integer`	Limits: `≥ 2, ≤ 200`
problem_spec.`include_binary_diff`	`boolean`
`additional_files`	`map<string, file_object>`
`cantera_args`	`object`
cantera_args.`loglevel`	`integer`	Limits: `≥ 0`
cantera_args.`max_steps`	`integer`	Limits: `≥ 1`
cantera_args.`output_interval`	`integer`	Limits: `≥ 1`
cantera_args.`chemkin_thermo`	`string`	Limits: `min length 1`
cantera_args.`chemkin_transport`	`string`	Limits: `min length 1`
cantera_args.`chemkin_permissive`	`boolean`

File fields take {"name": "x.pdb", "content_b64": "…"} or a stored artifact, {"$artifact": {"id": "art-…", "port": "…"}}. Files are up to 25 MiB each.

Example

from cognichem_client import CogniChem

client = CogniChem.from_env()  # reads COGNICHEM_API_KEY
payload = {
    "mode": "equilibrium",
    "mechanism": {"name": "h2o2.yaml", "content_b64": "<file contents, base64>"},
    "problem_spec": {
        "temperature": 1500,
        "pressure": 101325,
        "composition": "H2:2, O2:1",
    },
}

estimate = client.jobs.estimate(job_type="cantera", payload=payload, resource="cpu")
print(f"Reserves ${estimate.cost:.2f}")

job = client.jobs.submit(
    job_name="my-cantera-run",
    job_type="cantera",
    payload=payload,
    resource="cpu",
)
status = client.jobs.wait(job.process_id)
if status.status == "completed":
    client.jobs.result(job.process_id, save_path=".")

curl -X POST "https://api.cognichem.com/api/v1/jobs/submit" \
  -H "X-Api-Key: $COGNICHEM_API_KEY" \
  -H "Idempotency-Key: $(uuidgen)" \
  -H "Content-Type: application/json" \
  -d '{
  "job_name": "my-cantera-run",
  "job_type": "cantera",
  "payload": {
    "mode": "equilibrium",
    "mechanism": {
      "name": "h2o2.yaml",
      "content_b64": "<file contents, base64>"
    },
    "problem_spec": {
      "temperature": 1500,
      "pressure": 101325,
      "composition": "H2:2, O2:1"
    }
  },
  "resource": "cpu"
}'

{
  "mode": "equilibrium",
  "mechanism": {
    "name": "h2o2.yaml",
    "content_b64": "<file contents, base64>"
  },
  "problem_spec": {
    "temperature": 1500,
    "pressure": 101325,
    "composition": "H2:2, O2:1"
  }
}

Sample data from the job catalog; long values are shortened here. Each job_name must be unique among your jobs.

Workflow inputs

Kinetic mechanism · optionalYAML, CTI, XML, CHEMKIN

Workflow outputs

ArchiveZIP
TableCSV
TableCSV
TableCSV
TableCSV
TableCSV

Inputs

Outputs

Chaining

Not covered

Run it from the API

Cantera cantera

Cantera `cantera`