Multi-physics analysis of a 1 MW gyrotron cavity cooled by mini-channels

Bertinetti, Andrea; Avramidis, Konstantinos A.; Albajar, F.; Cau, Francesca; Cismondi, F.; Rozier, Y.; Savoldi, Laura; Zanino, Roberto

doi:10.1016/j.fusengdes.2017.05.016

Cited by 23 publications

(16 citation statements)

References 7 publications

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“…Therefore, it is mandatory to implement an efficient water cooling system. For the first operation an annular gap cooling system is implemented, which shows in simulation a maximum surface temperature of 350 °C [11] in CW operation.. To reduce the maximum temperature and also improve the homogeneity of temperature distribution, an advanced micro-channel cooling system [12] is under investigation.…”

Section: B Cavitymentioning

confidence: 99%

KIT in-house manufacturing and first operation of a 170 GHz 2 MW longer-pulse coaxial-cavity pre-prototype gyrotron

Ruess

Avramidis²,

Gantenbein³

et al. 2018

2018 11th German Microwave Conference (GeMiC)

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In frame of the work package "Heating and Current Drive" within the HORIZON 2020 EUROfusion program the development of multi-megawatt gyrotrons for the DEMOnstration fusion power plant is ongoing at KIT. Additionally, possible future upgrades of gyrotrons for e.g. for W7-X and ITER, are under consideration. Using the KIT modular-type 170 GHz 2 MW shortpulse (ms-range) coaxial-cavity pre-prototype the superior performance of the coaxial-cavity gyrotron technology has been already demonstrated for pulse lengths of up to a few milliseconds, achieving an RF output power of 2.2 MW. This short-pulse preprototype is now being upgraded in two steps to allow investigation of long-pulse behavior. The first step allows pulse-lengths up to 100 ms. The second step shall allow pulse-lengths up to 1 s. The first step in the upgrade was finished just recently. Considering a multi-megawatt output power at around 50 % total efficiency of the tube, the upgrade of the pre-prototype did require significant developments in the areas of basic construction, in particular with regards to cooling technologies, and in the final assembly. In this paper, the basic construction, the manufacturing details and the assembly are shown. Additionally, it is planned to show the very first performance results of the long-pulse tube based on the measurements which will be achieved in the time frame before the conference.

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Section: B Cavitymentioning

confidence: 99%

KIT in-house manufacturing and first operation of a 170 GHz 2 MW longer-pulse coaxial-cavity pre-prototype gyrotron

Ruess

Avramidis²,

Gantenbein³

et al. 2018

2018 11th German Microwave Conference (GeMiC)

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show abstract

“…With the nominal operating condition, it had to be checked that the insert would be able to withstand CW operation without significant deformation. The overview of the adopted simulation approach is presented in Figure 2 and it is similar to that used in [3] [7]. First, with help of the electromagnetic (EM) simulation, the heat flux corresponding to the original geometry is calculated at room temperature.…”

Section: Simulation Set-upmentioning

confidence: 99%

“…The increase in temperature results in deformations of cavity wall and insert, which further modifies the operating conditions, the generated RF waves, and the total heat flux. The effectiveness of various cooling systems for the cavity outer wall has been studied systematically in [3][4][5][6][7]. In the present work, the performance of the existing insert cooling system is numerically verified for CW operation of a 2 MW 170 GHz coaxial-cavity gyrotron [8].…”

Section: Introductionmentioning

confidence: 99%

Performance analysis of an insert cooling system for long-pulse operation of a coaxial-cavity gyrotron

Kalaria

George

Uly

et al. 2018

2018 IEEE International Vacuum Electronics Conference (IVEC)

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The successful operation of a 2 MW 170 GHz coaxial-cavity gyrotron has been demonstrated at IHM-KIT in short(ms) pulses and the ongoing research activities are aiming to upgrade the existing tube to the long-pulse regime. In this work, the performance of the insert cooling system is systematically studied for longpulse coaxial-cavity gyrotron operation. A multi-physics simulation model is developed with the relevant turbulence model and mesh parameters. The results suggest stable operation of the insert under continuous wave (CW) operating condition. In the case of perfectly aligned insert, the maximum temperature of the cooling water is below the boiling temperature and the deformations of the insert geometry are significantly small enough not to influence the performance of the gyrotron. Additionally, the operational limits of the insert cooling system are determined with respect to the maximum allowable heatflux.

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“…In order to improve the heat management of cavities, targeted to the design of higher-RF-efficiency tubes, several alternative options are being investigated, such as axial or longitudinal grooves [10] or mini-channels (MC) [11][12][13][14]. The MC cooling option was tested in a planar cavity mock-up at the Areva premises [13], in conditions relevant for the cavity operation [15].…”

Section: Introductionmentioning

confidence: 99%

Test and Modeling of the Hydraulic Performance of High-Efficiency Cooling Configurations for Gyrotron Resonance Cavities

et al. 2020

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The design and manufacturing of different full-size mock-ups of the resonance cavity of gyrotrons, relevant for fusion applications, were performed according to two different cooling strategies. The first one relies on mini-channels, which are very promising in the direction of increasing the heat transfer in the heavily loaded cavity, but which could face an excessively large pressure drop, while the second one adopts the solution of Raschig rings, already successfully used in European operating gyrotrons. The mock-ups, manufactured with conventional techniques, were hydraulically characterized at the Thales premises, using water at room temperature. The measured pressure drop data were used to validate the corresponding numerical computational fluid dynamics (CFD) models, developed with the commercial software STAR-CCM+ (Siemens PLM Software, Plano TX, U.S.A.) and resulting in excellent agreement with the test results. When the validated models were used to compare the two optimized cooling configurations, it resulted that, for the same water flow, the mini-channel strategy gave a pressure drop was two-fold greater than that of the Raschig rings strategy, allowing a maximum flow rate of 1 × 10−3 m3/s to meet a maximum allowable pressure drop of 0.5 MPa.

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Multi-physics analysis of a 1 MW gyrotron cavity cooled by mini-channels

Cited by 23 publications

References 7 publications

KIT in-house manufacturing and first operation of a 170 GHz 2 MW longer-pulse coaxial-cavity pre-prototype gyrotron

KIT in-house manufacturing and first operation of a 170 GHz 2 MW longer-pulse coaxial-cavity pre-prototype gyrotron

Performance analysis of an insert cooling system for long-pulse operation of a coaxial-cavity gyrotron

Test and Modeling of the Hydraulic Performance of High-Efficiency Cooling Configurations for Gyrotron Resonance Cavities

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