Numerical investigation of collector cooling for a 1 MW ITER gyrotron operated with vertical sweeping

Towards the optimization of the thermal–hydraulic performance of gyrotron collectors

“…In our previous work [14] on the thermal-hydraulic performance of the HV-like collector with AR = 3 we already discussed the selection of:…”

“…The analysis of the mesh independence of the computed solution was also discussed in [14]. Here we shall therefore stick to the recipes developed in that context.…”

“…Therefore, the thermal analysis performed considering the average steady-state heat load is not conservative [14].…”

“…In our previous work [14], the StarCCM+ commercial CFD code was applied to the analysis of an HV-like geometry adopting deep rectangular cavities 1 with aspect ratio (AR) = depth/width = 3, which has already been used in several gyrotron tubes 2 . While for steady state heat load up to 5 MW/m 2 this solution proved to be acceptable, concerning the capability to keep the collector below a maximum acceptable Cu temperature of 300 • C, when the actual transient heat load was considered (in combination with a vertical sweeping scenario) this threshold was overcome.…”

“…The paper is organized as follows: in Section 2 the model already discussed in detail in [14] is briefly reviewed; in Section 3 the results of the steady-state thermal-hydraulic analysis are presented for different collector geometries, including rectangular cavities with different aspect ratios, circumferential ribs (CR) and half-ball dimples (HBD); in Section 4 the results of the transient thermal-hydraulic analysis are presented for the most promising collector geometries. Conclusions are drawn in Section 5.…”