Two-phase flow pressure drop of liquid nitrogen boiling in the straight section downstream of U-bend

Deng, Dameng; Xie, Siwei; Wang, Rongshun

doi:10.1007/s12204-014-1530-6

Cited by 1 publication

(1 citation statement)

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“…Bubbles near the inner side of the bend entrance momentarily pause and merge with subsequent inflowing bubbles before entering the bend. This phenomenon was also observed by Deng Dong [24] in visual experiments on liquid nitrogen flow through bends, where bubbles seemed to be momentarily "frozen". This phenomenon occurs because the fluid behavior is complex at the bend, and there is significant local resistance at the bend entrance.…”

Section: Gas-liquid Two-phase Flow Simulationsupporting

confidence: 66%

Research on the Mechanism of Flow-Induced Vibration in the Cooling System of a Double Crystal Monochromator

Li,

Gong,

Bai

et al. 2024

Applied Sciences

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To investigate the mechanism of flow-induced vibrations in the cooling system of a double crystal monochromator (DCM), this paper utilizes a multi-physics numerical simulation approach, employing ANSYS and FLUENT platforms to simulate the flow state of liquid nitrogen in the cooling system and explore the amplitude response of the DCM. Initially, simulations were conducted to examine the flow state of liquid nitrogen with varying frequency and amplitude pulsations. Subsequently, modal analysis was employed to investigate the amplitude response of the DCM in the pitch direction vibrations under pulsating excitation. Finally, this research investigated the influence of high heat load-induced liquid nitrogen boiling on a DCM. The results indicate that pipe resistance is the fundamental cause of vibration induced by pulsating excitation. Low-frequency excitation enhances the amplification factor of DCM vibration. In contrast, due to the rapid conversion of fluid kinetic energy to pressure potential energy, high-frequency excitation increases the pulsation amplitude in the pipe. Additionally, there is a linear relationship between the amplitude of liquid nitrogen velocity fluctuations and the response amplitude of a DCM. The slug flow formed after liquid nitrogen boiling generates low-frequency pulse signals, and intermittent fluid impacts cause significant vibrations in the DCM. These research findings provide a reference for the analysis and design of ultra-high-stability DCM cooling systems.

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Section: Gas-liquid Two-phase Flow Simulationsupporting

confidence: 66%