.TRANSFORM.HeatExchangers.GenericDistributed_HX.FlowModel_shell .TRANSFORM.HeatExchangers.GenericDistributed_HX.FlowModel_shellmodel FlowModel_shell = TRANSFORM.Fluid.ClosureRelations.PressureLoss.Models.DistributedPipe_1D.SinglePhase_Developed_2Region_NumStable;