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.