Development and demonstration of a supercritical helium-cooled cryogenic viscous compressor prototype for the iter vacuum system

Duckworth, R. C.; Baylor, L. R.; Meitner, S. J.; Combs, S. K.; Rasmussen, D. A.; Hechler, M.; Edgemon, Timothy; Barbier, Charlotte; Pearce, R.; Kersevan, R.; Dremel, M.; Boissin, J.C.

doi:10.1063/1.4707046

Cited by 4 publications

(9 citation statements)

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“…The Penning gauge has been successfully used in similar configurations to discern gas composition in vacuum systems as it relates to fusion-based reactions and dynamics [11][12][13]. Previous testing [10] simply measured the internal pressure as the frozen deuterium would sublimate. Further analysis revealed that the regeneration pressure did not provide a consistent estimate due to temperature variation in the setup from test to test.…”

Section: Experimental Setup and Proceduresmentioning

confidence: 99%

“…While the prototype CVC single tube test assembly has been presented previously [10], a brief description is provided here in order to provide the appropriate context for the experimental results as well as present some of the modifications that have been made from the initial design. The prototype CVC single tube test assembly, which is shown in Fig.…”

Section: Experimental Setup and Proceduresmentioning

confidence: 99%

“…In order to improve the mixing of the gas with the tubular walls without producing a high pressure drop across the tubular elements, extended surfaces that are connected to the tubular walls were considered. Given the significant investment to build a full-scale CVC prototype with 24 tubular elements and the time-consuming and complex nature of modeling of freezing and gas transport of hydrogen gases in threedimensions, a prototype CVC single tube test assembly was successfully designed, fabricated, and commissioned to serve a test bed for tubular elements with different flow enhancement concepts under representative conditions [10].…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of static mixer flow enhancements for cryogenic viscous compressor prototype for ITER vacuum system

Duckworth¹,

Baylor²,

Meitner³

et al. 2014

AIP Conference Proceedings

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Abstract. As part of the U.S. ITER contribution to the vacuum systems for the ITER fusion project, a cryogenic viscous compressor (CVC) is being designed and fabricated to cryopump hydrogenic gases in the torus and neutral beam exhaust streams and to regenerate the collected gases to controlled pressures such that they can be mechanically pumped with controlled flows to the tritium reprocessing facility. One critical element of the CVC design that required additional investigation was the determination of flow rates of the low pressure (up to 1000 Pa) exhaust stream that would allow for complete pumping of hydrogenic gases while permitting trace levels of helium to pass through the CVC to be pumped by conventional vacuum pumps. A sub-scale prototype test facility was utilized to determine the effectiveness of a static mixer pump tube concept, which consisted of a series of rotated twisted elements brazed into a 2-mm thick, 5-cm diameter stainless steel tube. Cold helium gas flow provided by a dewar and helium transfer line was used to cool the exterior of the static mixer pump tube. Deuterium gas was mixed with helium gas through flow controllers at different concentrations while the composition of the exhaust gas was monitored with a Penning gauge and optical spectrometer to determine the effectiveness of the static mixer. It was found that with tube wall temperatures between 6 K and 9 K, the deuterium gas was completely cryopumped and only helium passed through the tube. These results have been used to design the cooling geometry and the static mixer pump tubes in the full-scale CVC prototype

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Section: Experimental Setup and Proceduresmentioning

confidence: 99%

Section: Experimental Setup and Proceduresmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Evaluation of static mixer flow enhancements for cryogenic viscous compressor prototype for ITER vacuum system

Duckworth¹,

Baylor²,

Meitner³

et al. 2014

AIP Conference Proceedings

Self Cite

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“…A helium coolant (supercritical helium or cold helium gas) flows through the outer annular pipe. A full description and visual depiction of the cryogenic fore pump can be found in our colleagues' publications [2,3]. Figure 1 shows a differential control volume of the CFP model.…”

Section: Introductionmentioning

confidence: 99%

“…At Oak Ridge National Lab, a prototype CFP has been built and tested [2,3], while efforts at the University of Wisconsin-Madison, have focused on the physical analysis and modeling. The experimental results provide a reference for the theoretical models, and the theoretical work can provide guidance for future experiments.…”

Section: Introductionmentioning

confidence: 99%

Modeling results for the ITER cryogenic fore pump

Zhang¹,

Miller²,

Pfotenhauer³

2014

AIP Conference Proceedings

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Abstract. The cryogenic fore pump (CFP) is designed for ITER to collect and compress hydrogen isotopes during the regeneration process of torus cryopumps. Different from common cryopumps, the ITER-CFP works in the viscous flow regime. As a result, both adsorption boundary conditions and transport phenomena contribute unique features to the pump performance. In this report, the physical mechanisms of cryopumping are studied, especially the diffusionadsorption process and these are coupled with standard equations of species, momentum and energy balance, as well as the equation of state. Numerical models are developed, which include highly coupled non-linear conservation equations of species, momentum and energy and equation of state. Thermal and kinetic properties are treated as functions of temperature, pressure, and composition. To solve such a set of equations, a novel numerical technique, identified as the Group-Member numerical technique is proposed. It is presented here a 1D numerical model. The results include comparison with the experimental data of pure hydrogen flow and a prediction for hydrogen flow with trace helium. An advanced 2D model and detailed explanation of the Group-Member technique are to be presented in following papers.

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Solid deposition in the ITER cryogenic viscous compressor

2016

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A transient model for the ITER cryogenic viscous compressor (CVC) is presented. The CVC is designed to separate hydrogen isotopes from helium in the gasmixture exhaust from the ITER torus. During their residence in the CVC, hydrogen isotopes are captured along the pump wall while helium flows through. The CVC thereby provides the first stage of helium compression. The transient model characterizes the transport phenomena (species, momentum, and energy) that occur in the CVC. The numerical results are compared with experimental data from a scaled down test of the ITER CVC using pure hydrogen. Although the model has been developed for a hydrogen-helium mixture, it is simplified here in order to compare with the experimental data. The transient model, along with other numerical models we have developed, provide guidance for the design and optimization of the ITER CVC. The model can also be a useful tool or a reference for similar analyses, such as those for cryogenic carbon capture and air ingress in vacuum isolated cryogenic vessels.

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Development and demonstration of a supercritical helium-cooled cryogenic viscous compressor prototype for the iter vacuum system

Cited by 4 publications

References 0 publications

Evaluation of static mixer flow enhancements for cryogenic viscous compressor prototype for ITER vacuum system

Evaluation of static mixer flow enhancements for cryogenic viscous compressor prototype for ITER vacuum system

Modeling results for the ITER cryogenic fore pump

Solid deposition in the ITER cryogenic viscous compressor

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