.ClaRa.SubSystems.Furnace.ConvectiveSlice_L4.GasHeatTransfer_CarrierTubes .ClaRa.SubSystems.Furnace.ConvectiveSlice_L4.GasHeatTransfer_CarrierTubesmodel GasHeatTransfer_CarrierTubes = ClaRa.Basics.ControlVolumes.Fundamentals.HeatTransport.Gas_HT.Convection.Convection_carrierTubes_turbulent_L2;