A conceptual design of the calorimeter for the Neutral Beam Injector (NBI) of the Divertor Test Tokamak (DTT) has been developed. The DTT NBI calorimeter features two beam stopping panels made of CuCrZr cooled by pressurized water flowing through deep drilled cooling pipes with twisted tape insertions. The proposed design is based primarily on the expected beam power distribution of DTT NBI, thermal-hydraulic factors (maximum temperature of the structure and coolant, pressure drop) and geometrical constraints (beam cross-section, panel inclination angle, available space for the calorimeter, etc.). Main design choices are made on the basis of thoroughly verified CFD simulation results, leading to an optimized design in terms of minimizing the structure and coolant temperatures while respecting the operating conditions, allowed pressure drop in the cooling circuit and overall space constraints. Inlet and outlet manifolds are designed to evenly distribute the coolant (as much as possible) through the calorimeter cooling pipes. The mechanical response of the calorimeter structures, in terms of deformations and stresses, has been analyzed on the optimized design. The thermo-mechanical analyses were first performed on the smaller section of the panel using the temperature distribution in the solid structure obtained from CFD simulations and applying a constant coolant pressure of 2 MPa on the calorimeter pipes. The analyses on the reduced model enable better understanding of its thermo-mechanical response under pressure and thermal loads separately and under different boundary conditions. The follow-up thermo-mechanical simulations of the whole panel use the heat transfer coefficient on the coolant-solid interface that has been previously calculated from the dedicated fluid-solid CFD simulation of the reduced model. It has been shown that thermal loads dominate the deformations and stresses in the calorimeter. The results are evaluated against appropriate structural design criteria.
Calorimeter conceptual design for Neutral Beam Injector of DTT - CFD optimisation and thermal stress analysis
Agostinetti Piero
2020
Abstract
A conceptual design of the calorimeter for the Neutral Beam Injector (NBI) of the Divertor Test Tokamak (DTT) has been developed. The DTT NBI calorimeter features two beam stopping panels made of CuCrZr cooled by pressurized water flowing through deep drilled cooling pipes with twisted tape insertions. The proposed design is based primarily on the expected beam power distribution of DTT NBI, thermal-hydraulic factors (maximum temperature of the structure and coolant, pressure drop) and geometrical constraints (beam cross-section, panel inclination angle, available space for the calorimeter, etc.). Main design choices are made on the basis of thoroughly verified CFD simulation results, leading to an optimized design in terms of minimizing the structure and coolant temperatures while respecting the operating conditions, allowed pressure drop in the cooling circuit and overall space constraints. Inlet and outlet manifolds are designed to evenly distribute the coolant (as much as possible) through the calorimeter cooling pipes. The mechanical response of the calorimeter structures, in terms of deformations and stresses, has been analyzed on the optimized design. The thermo-mechanical analyses were first performed on the smaller section of the panel using the temperature distribution in the solid structure obtained from CFD simulations and applying a constant coolant pressure of 2 MPa on the calorimeter pipes. The analyses on the reduced model enable better understanding of its thermo-mechanical response under pressure and thermal loads separately and under different boundary conditions. The follow-up thermo-mechanical simulations of the whole panel use the heat transfer coefficient on the coolant-solid interface that has been previously calculated from the dedicated fluid-solid CFD simulation of the reduced model. It has been shown that thermal loads dominate the deformations and stresses in the calorimeter. The results are evaluated against appropriate structural design criteria.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
