{
  "schema_version": "1",
  "name": "Capillary Tube R134a Smoke",
  "description": "WIP smoke fixture: RefrigerantSource → CapillaryTube → RefrigerantSink. DoF can square, but CapillaryTube Component residuals are still stubs (mass/enthalpy continuity only — no frictional ΔP residual), so the Newton Jacobian is singular. Kept for parsing/wiring tests; not yet a UI Load example.",

  "fluid": "R134a",
  "fluid_backend": "CoolProp",

  "circuits": [
    {
      "id": 0,
      "name": "Capillary smoke",
      "components": [
        {
          "type": "RefrigerantSource",
          "name": "src",
          "fluid": "R134a",
          "p_set_bar": 12.0,
          "quality": 0.0
        },
        {
          "type": "CapillaryTube",
          "name": "cap",
          "diameter_m": 0.0012,
          "length_m": 1.8,
          "n_segments": 24,
          "p_inlet_bar": 12.0,
          "h_inlet_kj_kg": 250.0,
          "p_outlet_bar": 3.5,
          "h_outlet_kj_kg": 250.0
        },
        {
          "type": "RefrigerantSink",
          "name": "sink",
          "fluid": "R134a",
          "p_back_bar": 3.5
        }
      ],
      "edges": [
        { "from": "src:outlet", "to": "cap:inlet" },
        { "from": "cap:outlet", "to": "sink:inlet" }
      ]
    }
  ],

  "solver": {
    "strategy": "newton",
    "max_iterations": 50,
    "tolerance": 1e-6
  }
}