Goal of this task is to give a design of the front mirror for the construction of a fullscale mock-up of the mm-wave transmission line for the ITER upper launcher at 170 GHz [1]. Taking into account that the optimal configuration must, at the end, provide steady state operation at safe temperature levels, limit thermal distortions within an amount not affecting the reflected beam shape, safely withstand electrodynamic forces in case of VDE, it turns out that active cooling of the front mirror in the arrangement imposed by physics applications and port integration is a very challenging task. Although the mock-up will not experience some of the extreme conditions expected in ITER, nevertheless possible tests on the mock-up would be meaningful only if the mirror itself is very similar to the operational one. I follows that most of the work has been done for identifying a path to optimization, by evaluating different effects and testing different configurations. In this work: - The ohmic power distribution determined by the beam reflection losses on the RS end-mirror is estimated around 15 MW/m2 for copper at the worst beam spot position. - From experience on 2-D and 3-D models, the effect of copper layer thickness on stresses, the peak temperature and the largest mirror deformations are estimated. - The need of limiting the highest temperatures, to avoid yield, by appropriate choice of the distance between the cooling channels and the copper surface, and by improving heat exchange coefficient, is discussed. - Two detailed designs of cooling channels are investigated (small semi-circular channels and swirled tubes) with thermo-mechanical calculations: results are given of temperature distribution and evaluation of stresses and deformations. The choice between the two can be performed considering manufacturing ease. - A manufacturing procedure has been suggested, considering solid HIP or drilled holes with a successive bending. - The correct quantification of the reflection losses on the mirror surface, crucial for the design of the mirror structure and cooling circuit, has been started, giving a more detailed picture of the safety factors to be used.
Detailed design of end-mirror, including material selection & Cooling arrangements, FINAL REPORT for Deliverable (e).4.1 EFDA Task TW3-TPHE-ECHULB4
Bruschi A;Cirant S
2005
Abstract
Goal of this task is to give a design of the front mirror for the construction of a fullscale mock-up of the mm-wave transmission line for the ITER upper launcher at 170 GHz [1]. Taking into account that the optimal configuration must, at the end, provide steady state operation at safe temperature levels, limit thermal distortions within an amount not affecting the reflected beam shape, safely withstand electrodynamic forces in case of VDE, it turns out that active cooling of the front mirror in the arrangement imposed by physics applications and port integration is a very challenging task. Although the mock-up will not experience some of the extreme conditions expected in ITER, nevertheless possible tests on the mock-up would be meaningful only if the mirror itself is very similar to the operational one. I follows that most of the work has been done for identifying a path to optimization, by evaluating different effects and testing different configurations. In this work: - The ohmic power distribution determined by the beam reflection losses on the RS end-mirror is estimated around 15 MW/m2 for copper at the worst beam spot position. - From experience on 2-D and 3-D models, the effect of copper layer thickness on stresses, the peak temperature and the largest mirror deformations are estimated. - The need of limiting the highest temperatures, to avoid yield, by appropriate choice of the distance between the cooling channels and the copper surface, and by improving heat exchange coefficient, is discussed. - Two detailed designs of cooling channels are investigated (small semi-circular channels and swirled tubes) with thermo-mechanical calculations: results are given of temperature distribution and evaluation of stresses and deformations. The choice between the two can be performed considering manufacturing ease. - A manufacturing procedure has been suggested, considering solid HIP or drilled holes with a successive bending. - The correct quantification of the reflection losses on the mirror surface, crucial for the design of the mirror structure and cooling circuit, has been started, giving a more detailed picture of the safety factors to be used.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
