| Integer | N | 2 | Number of nodes for thermal variables |
| Integer | Nw | N - 1 | Number of volumes on the wall interface |
| Integer | Nt | 1 | Number of tubes in parallel |
| SI.Distance | L | | Tube length |
| SI.Position | H | 0 | Elevation of outlet over inlet |
| SI.Area | A | | Cross-sectional area (single tube) |
| SI.Length | omega | | Perimeter of heat transfer surface (single tube) |
| SI.Length | Dhyd | | Hydraulic Diameter (single tube) |
| Medium.MassFlowRate | wnom | | Nominal mass flowrate (total) |
| ThermoPower.Choices.Flow1D.FFtypes | FFtype | ThermoPower.Choices.Flow1D.FFtypes.NoFriction | Friction Factor Type |
| SI.PressureDifference | dpnom | 0 | Nominal pressure drop |
| Real | Kfnom | 0 | Nominal hydraulic resistance coefficient |
| Medium.Density | rhonom | 0 | Nominal inlet density |
| SI.PerUnit | Cfnom | 0 | Nominal Fanning friction factor |
| SI.PerUnit | e | 0 | Relative roughness (ratio roughness/diameter) |
| Real | Kfc | 1 | Friction factor correction coefficient |
| Boolean | DynamicMomentum | false | Inertial phenomena accounted for |
| Boolean | UniformComposition | true | Uniform gas composition is assumed |
| Boolean | QuasiStatic | false | Quasi-static model (mass, energy and momentum static balances |
| HCtypes | HydraulicCapacitance | HCtypes.Downstream | 1: Upstream, 2: Downstream |
| Boolean | avoidInletEnthalpyDerivative | true | Avoid inlet enthalpy derivative |
| Boolean | allowFlowReversal | system.allowFlowReversal | = true to allow flow reversal, false restricts to design direction |
| SI.Velocity | unom | 10 | Nominal velocity for simplified equation |
| Real | wnf | 0.01 | Fraction of nominal flow rate at which linear friction equals turbulent friction |
| Initialisation |
| Medium.AbsolutePressure | pstart | 1e5 | Pressure start value |
| Medium.Temperature | Tstartbar | 300 | Avarage temperature start value |
| Medium.Temperature | Tstartin | Tstartbar | Inlet temperature start value |
| Medium.Temperature | Tstartout | Tstartbar | Outlet temperature start value |
| Medium.Temperature[N] | Tstart | linspace(Tstartin, Tstartout, N) | Start value of temperature vector (initialized by default) |
| Medium.MassFraction[nX] | Xstart | Medium.reference_X | Start gas composition |
| Choices.Init.Options | initOpt | system.initOpt | Initialisation option |
| Boolean | noInitialPressure | false | Remove initial equation on pressure |
Medium
squareReg