Implementing bubbly mercury material model (R-P model) in the pulse simulation to predict strain on the Spallation Neutron Source target vessel with gas injection

Hao Jiang; Drew E. Winder; Charlotte Barbier; Bernard W. Riemer

doi:10.1016/j.rinp.2023.106511

Implementing bubbly mercury material model (R-P model) in the pulse simulation to predict strain on the Spallation Neutron Source target vessel with gas injection

Hao Jiang, Drew E. Winder, Charlotte Barbier, Bernard W. Riemer

Research output: Contribution to journal › Article › peer-review

3 Scopus citations

Abstract

The Spallation Neutron Source (SNS) creates neutrons by striking a liquid mercury target with short pulses of high-energy protons. SNS targets have been operated with helium microbubble gas injection into portions of the flowing mercury since 2017. The measurements during in situ testing showed that the strain response of the stainless steel target vessel significantly decreased with gas injection. Strain reductions ranged from 40% to 75% for targets operating with gas-injection rates between 2 and 3 standard liters per minute. These strain reductions have allowed SNS to operate reliably at 1.4 MW over the last few years and are expected to significantly improve the fatigue life of the target vessel. The achieved mitigation of the pulse response and the associated cavitation damage with gas injection is a cornerstone of the upgrade basis to the redesigned mercury vessel for planned higher power operation. Existing methods can simulate the structural response of the target operated without gas injection. Developing simulation techniques that account for the benefits of gas injection adds a considerable challenge. A combined mercury/bubble material model based on the Rayleigh–Plesset equation was developed to improve simulation of the response of a structure containing liquid and gas by incorporating bubble growth volume feedback. This paper details the implementation of the mercury/bubble material model in the pulse simulation of an existing target design. The newly developed simulation technique combines the current no-gas mercury material model for no-gas regions and the bubbly mercury material model for the regions with gas bubbles. The results of the strain response simulation using the new techniques are promising. The challenges of the technique development are also discussed. For example, the bubble size distributions are crucial for the simulations but remain an area of active research.

Original language	English
Article number	106511
Journal	Results in Physics
Volume	49
DOIs	https://doi.org/10.1016/j.rinp.2023.106511
State	Published - Jun 2023
Externally published	Yes

Funding

The authors would like to acknowledge the contributions of Elvis Dominguez-Ontiveros for providing insightful comments from his valuable understanding of fluid dynamic and multi-phase flow, and his testing results on water flow at TTF in SNS, as well as for reviewing the paper. The authors appreciated Justin Weinmeister for providing BSD measurement data on mercury flow at TTF in SNS. We would also like to recognize individuals who contributed to strain measurement, Yun Liu, Cary D. Long, Robert L. Sangrey, Charles C. Peters, David Brown, Willem Blokland and Kevin Johns. The SNS is sponsored by the Office of Science, U.S. Department of Energy, and managed by UT-Battelle, LLC for the U.S. Department of Energy under Contract DE-AC05-00OR22725.

Funders	Funder number
U.S. Department of Energy
Office of Science
UT-Battelle	DE-AC05-00OR22725

Keywords

Bubble size distribution
Gas injection
Mercury material model
Spallation neutron source
Strain measurement
Strain simulation
Target

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10.1016/j.rinp.2023.106511

Cite this

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title = "Implementing bubbly mercury material model (R-P model) in the pulse simulation to predict strain on the Spallation Neutron Source target vessel with gas injection",

abstract = "The Spallation Neutron Source (SNS) creates neutrons by striking a liquid mercury target with short pulses of high-energy protons. SNS targets have been operated with helium microbubble gas injection into portions of the flowing mercury since 2017. The measurements during in situ testing showed that the strain response of the stainless steel target vessel significantly decreased with gas injection. Strain reductions ranged from 40% to 75% for targets operating with gas-injection rates between 2 and 3 standard liters per minute. These strain reductions have allowed SNS to operate reliably at 1.4 MW over the last few years and are expected to significantly improve the fatigue life of the target vessel. The achieved mitigation of the pulse response and the associated cavitation damage with gas injection is a cornerstone of the upgrade basis to the redesigned mercury vessel for planned higher power operation. Existing methods can simulate the structural response of the target operated without gas injection. Developing simulation techniques that account for the benefits of gas injection adds a considerable challenge. A combined mercury/bubble material model based on the Rayleigh–Plesset equation was developed to improve simulation of the response of a structure containing liquid and gas by incorporating bubble growth volume feedback. This paper details the implementation of the mercury/bubble material model in the pulse simulation of an existing target design. The newly developed simulation technique combines the current no-gas mercury material model for no-gas regions and the bubbly mercury material model for the regions with gas bubbles. The results of the strain response simulation using the new techniques are promising. The challenges of the technique development are also discussed. For example, the bubble size distributions are crucial for the simulations but remain an area of active research.",

keywords = "Bubble size distribution, Gas injection, Mercury material model, Spallation neutron source, Strain measurement, Strain simulation, Target",

author = "Hao Jiang and Winder, {Drew E.} and Charlotte Barbier and Riemer, {Bernard W.}",

note = "Publisher Copyright: {\textcopyright} 2023 The Authors",

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AU - Jiang, Hao

AU - Winder, Drew E.

AU - Barbier, Charlotte

AU - Riemer, Bernard W.

PY - 2023/6

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N2 - The Spallation Neutron Source (SNS) creates neutrons by striking a liquid mercury target with short pulses of high-energy protons. SNS targets have been operated with helium microbubble gas injection into portions of the flowing mercury since 2017. The measurements during in situ testing showed that the strain response of the stainless steel target vessel significantly decreased with gas injection. Strain reductions ranged from 40% to 75% for targets operating with gas-injection rates between 2 and 3 standard liters per minute. These strain reductions have allowed SNS to operate reliably at 1.4 MW over the last few years and are expected to significantly improve the fatigue life of the target vessel. The achieved mitigation of the pulse response and the associated cavitation damage with gas injection is a cornerstone of the upgrade basis to the redesigned mercury vessel for planned higher power operation. Existing methods can simulate the structural response of the target operated without gas injection. Developing simulation techniques that account for the benefits of gas injection adds a considerable challenge. A combined mercury/bubble material model based on the Rayleigh–Plesset equation was developed to improve simulation of the response of a structure containing liquid and gas by incorporating bubble growth volume feedback. This paper details the implementation of the mercury/bubble material model in the pulse simulation of an existing target design. The newly developed simulation technique combines the current no-gas mercury material model for no-gas regions and the bubbly mercury material model for the regions with gas bubbles. The results of the strain response simulation using the new techniques are promising. The challenges of the technique development are also discussed. For example, the bubble size distributions are crucial for the simulations but remain an area of active research.

AB - The Spallation Neutron Source (SNS) creates neutrons by striking a liquid mercury target with short pulses of high-energy protons. SNS targets have been operated with helium microbubble gas injection into portions of the flowing mercury since 2017. The measurements during in situ testing showed that the strain response of the stainless steel target vessel significantly decreased with gas injection. Strain reductions ranged from 40% to 75% for targets operating with gas-injection rates between 2 and 3 standard liters per minute. These strain reductions have allowed SNS to operate reliably at 1.4 MW over the last few years and are expected to significantly improve the fatigue life of the target vessel. The achieved mitigation of the pulse response and the associated cavitation damage with gas injection is a cornerstone of the upgrade basis to the redesigned mercury vessel for planned higher power operation. Existing methods can simulate the structural response of the target operated without gas injection. Developing simulation techniques that account for the benefits of gas injection adds a considerable challenge. A combined mercury/bubble material model based on the Rayleigh–Plesset equation was developed to improve simulation of the response of a structure containing liquid and gas by incorporating bubble growth volume feedback. This paper details the implementation of the mercury/bubble material model in the pulse simulation of an existing target design. The newly developed simulation technique combines the current no-gas mercury material model for no-gas regions and the bubbly mercury material model for the regions with gas bubbles. The results of the strain response simulation using the new techniques are promising. The challenges of the technique development are also discussed. For example, the bubble size distributions are crucial for the simulations but remain an area of active research.

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Implementing bubbly mercury material model (R-P model) in the pulse simulation to predict strain on the Spallation Neutron Source target vessel with gas injection

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