Thermal-hydraulic analysis of an irregular sector of the ITER vacuum vessel by means of CFD tools

•3D Geometry healing and simplification for CFD simulations.•Meshing of large domains for CFD simulations.•Meshing procedure for fluid–solid interface coupling.•Hydraulics of the ITER VV Irregular Sector number 2 (IrS#2).•Thermal-hydraulics of the ITER VV IrS#2.

The present work exposes the 3D thermal-hydraulic analysis of the Irregular Sector number 2 (IrS#2) of the ITER Vacuum Vessel (VV) by means of CFD (computational fluid dynamics).IrS#2 geometry has been simplified and healed in order to be suitable for CFD analysis. A polyhedral cell based mesh has been generated so as to enhance accuracy and calculation stability. Nuclear heat deposition has been implemented through several subroutines and an in-house MCNP data converter.Water coolant and stainless steel shell are solved coupled as a steady-state conjugate heat transfer problem in order to assess the impact of the nuclear heat deposition on the IrS#2 cooling scheme. Hence, the IrS#2 is simulated as a whole without splitting the domain. Results show the total IrS#2 pressure drop as well as the flow and temperature distribution all over the IrS#2. Moreover, heat transfer coefficient has been calculated at the water–shell interface in order to assess the behavior of shell cooling scheme.Velocity magnitude in the water coolant has an average value of 2 cm/s and the inboard to outboard mass flow rate distribution is 10.2% and 89.8% respectively. Pressure drop, mainly at inlet and outlet ducts, is of 60.21 kPa. Temperature at the liquid–solid interface has an average value of 106.4 °C and the heat transfer coefficient (HTC) stays always above 638 W/(m2 °C), way above the limit of 500 W/(m2 °C). Shell temperature stays at an average value of 130.0 °C.Exposed results, with a significant importance regarding design and safety, give a valuable insight on current cooling scheme and system behavior for the IrS#2 of the ITER VV.