Analysis and optimization of LN2 two-phase flow in CRAFT NNBI cryopump

Qianxu Wang; Yuanlai Xie; Huihui Hong; Yang Zhu; Fang Wang; Kun Tian; Bin Li

Nuclear Engineering and Technology (Feb 2025)

Analysis and optimization of LN2 two-phase flow in CRAFT NNBI cryopump

Qianxu Wang,
Yuanlai Xie,
Huihui Hong,
Yang Zhu,
Fang Wang,
Kun Tian,
Bin Li

Affiliations

Qianxu Wang: Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, China; University of Science and Technology of China, Hefei, 230026, China
Yuanlai Xie: Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, China; Corresponding author.
Huihui Hong: Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, China; University of Science and Technology of China, Hefei, 230026, China
Yang Zhu: Hefei University of Technology, Hefei, 230009, China
Fang Wang: Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, China; University of Science and Technology of China, Hefei, 230026, China
Kun Tian: Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, China
Bin Li: Institute of Plasma Physics, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, 230031, China; University of Science and Technology of China, Hefei, 230026, China

Journal volume & issue: Vol. 57, no. 2
p. 103178

Abstract

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As an important component of Negative ion based Neutral Beam Injector (NNBI), the cryopump mainly provides a suitable vacuum environment for beam generation and transmission. In the paper, Liquid nitrogen (LN2) pipe structure models of two cryopumps were established for simulation and experimental studies. Thermal analysis of the thermal radiation shielding baffle (LN2 cooling) was carried out by Ansys steady-state thermal analysis software, while Fluent was used to simulate the two-phase flow in the LN2 pipeline, then the pressure drops, temperature, velocity, gas-phase volume fraction, and other parameters of the two pipeline structures were analyzed and compared. The simulation results show that the optimized structure B can reduce the pressure drop by 3 bar, the outlet temperature of structure A is 78.8 K, the outlet temperature of structure B is 79.2 K, the temperature difference is 0.4 K. The outlet velocity increases from 2.067 m/s to 4.947 m/s for Structure A, and from 1.096 m/s to 6.614 m/s for Structure B. The experiment results show that the outlet temperature of structure A is 79.4 K, meanwhile the outlet temperature of structure B is 80.1 K, the optimized structure B can reduce the pressure drop about 3 bar.

Published in Nuclear Engineering and Technology

ISSN: 1738-5733 (Print)
Publisher: Elsevier
Country of publisher: Korea, Republic of
LCC subjects: Technology: Electrical engineering. Electronics. Nuclear engineering: Nuclear engineering. Atomic power
Website: http://www.journals.elsevier.com/nuclear-engineering-and-technology

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