Article
Thermodynamics
Yichuan He, Chengzhi Hu, Hongyang Li, Xianfeng Hu, Dawei Tang
Summary: This study predicts bubble departure frequency in subcooling flow boiling using machine learning-based approaches. By comparing a consolidated dataset and nine regression models, it is found that the XGBoost model performs the best in predicting bubble departure frequency, providing a reliable tool.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Mathematics
Jinfeng Wang, Bingjun Wang, Jing Xie, Ke Lei, Bo Yu, Yuhang Sun
Summary: The study simulated three-dimensional subcooled flow boiling of R134a in a horizontal tube and explored bubble characteristics, identifying five representative bubbles. Results showed that bubble radial velocity is crucial for bubble departure, and heat flux, inlet velocity, and inlet subcooling all influence bubble departure diameter.
Article
Mechanics
Jiguo Tang, Xiao Li, Lingmiao Xu, Licheng Sun
Summary: Microbubble emission boiling (MEB) achieves high heat transfer beyond critical heat flux under highly subcooled boiling conditions. This study investigates the behavior of a vapor bubble and its induced liquid flow during subcooled boiling using high-speed two-phase particle image velocimetry method. Results show that MEB is accompanied by a rapid oscillating flow outside the bubble, which is different from nucleate boiling. The heat transfer of MEB is found to be dependent on liquid subcooling and heat flux, and a scaling law is derived for MEB heat transfer.
JOURNAL OF FLUID MECHANICS
(2023)
Article
Thermodynamics
Yujia Zhou, Jingyu Du, Chenru Zhao, Hanliang Bo, Yifan Zhang, Hongzhi Li
Summary: The dynamics of single bubbles in subcooled boiling flow is essential for understanding gas-liquid flow behavior and heat transfer. A numerical method is developed to capture the motion and condensation of bubbles, and the distribution of bubble position and size is investigated. The study reveals different modes of bubble size distribution at different radial positions and the mechanism of path instability of small bubbles near the wall.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Engineering, Environmental
Yuanjie LI, Shuai Ren, Shiwei Zhang, Xingchi Jiang, Chin Pan
Summary: Bubble characteristics are crucial for understanding two-phase flow dynamics and simulation. This study compared bubble characteristics in subcooled flow boiling of artificial seawater with that of de-ionized water, finding differences in bubble size distributions and foam flow structure. The results suggest that the bubble characteristics in artificial seawater are different from those in de-ionized water, with the foam flow structure in artificial seawater being comparatively rigid.
CHEMICAL ENGINEERING JOURNAL
(2022)
Review
Thermodynamics
Michel Kledy, Fabrice Francois, Henda Djeridi, Stephane Barre, Jean-Marc Delhaye
Summary: Forced convective boiling is an important phenomenon in nuclear plants, and accurately predicting a boiling crisis is essential. A new model based on mixture balance equations and submodels is developed and compared to experimental data, showing good performance in subcooled boiling but limitations in higher void fraction conditions.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Mechanics
Gulshan Kumar Sinha, Surya Narayan, Atul Srivastava
Summary: This study aims to investigate the dynamic characteristics of microlayer under nucleate flow boiling conditions, using water as the working fluid. Through thin-film interferometry combined with high-speed cinematography, the dynamic behavior of the microlayer and bubble growth process were simultaneously captured in a vertical rectangular channel.
JOURNAL OF FLUID MECHANICS
(2021)
Article
Thermodynamics
Il Woong Park, In Yeop Kang, Hyun Jin Yong
Summary: This study classified bubbles in two-phase flow and revealed the relationship between periodic bubble behavior and flow instability, providing an important theoretical basis for improving the application of flow boiling systems.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Mechanics
Nikhil Chitnavis, Harish Pothukuchi, B. S. V. Patnaik
Summary: The study investigates the bubble growth rate and departure mechanism in subcooled flow boiling conditions. An energy balance model is used to estimate the bubble growth rate, taking into account components such as microlayer evaporation, conduction, and condensation heat transfer. A force balance model predicts the bubble departure diameter and type. The models are validated against experimental data and a flow regime map is developed to identify bubble departure characteristics.
Review
Thermodynamics
Guang Yang, Wenchao Zhang, Maxime Binama, Qian Li, Weihua Cai
Summary: This article reviews the bubble dynamics involved in subcooled flow boiling, summarizing the current research status on models and applications. It discusses the behavior of bubbles and introduces important parameters related to bubble dynamics. It also examines bubble growth, departure, and lift-off behavior, as well as the factors influencing these processes. Additionally, it presents recent advances in bubble sliding and the application of bubble dynamics in boiling simulation.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Thermodynamics
Swapan Paruya, Jyoti Bhati, Farheen Akhtar
Summary: An improved numerical model was developed to simulate the dynamics of bubble shape and departure in nucleate pool boiling. The model was validated through comparisons with experimental and literature results. Bubble shape was found to be influenced by superheat and Bond number, with direct numerical integration of Young-Laplace working well for spherical bubbles and an approximate analytical solution working better for non-spherical bubbles.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Review
Thermodynamics
Guang Yang, Wenchao Zhang, Maxime Binama, Jianchuang Sun, Weihua Cai
Summary: This review discusses bubble dynamics involved in subcooled flow boiling and summarizes research methodologies in this field. It covers the topics of bubble dynamic mechanism model, experimental methods, and numerical methods.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Thermodynamics
Hyunsup Kim, Hyungmin Park
Summary: Experimental results show that the growth, departure, and collapse time of a vapor bubble decay exponentially with increasing subcooled temperature. In highly subcooled conditions, the bubble starts to shrink before departing, while in less subcooled conditions it does not shrink.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Il Woong Park, In Yeop Kang, Jia Yu, Yeon-Gun Lee
Summary: This study experimentally measured the bubble lift-off diameter on a flat heated surface under sub-cooled flow boiling conditions, and proposed a modified model that can predict the average size of bubbles.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2021)
Article
Thermodynamics
Xiaohuan Li, Xiande Fang, Yuxiang Fang, Zhiqiang He, Hongfeng Shang
Summary: The pool boiling heat transfer experiment conducted with pure water in hypergravity conditions showed that heat transfer enhancement was more pronounced in the fully developed region under saturation conditions. The effects of hypergravity became noticeable at higher heat flux levels in the natural convection region as the subcooling degrees increased. The main influence of hypergravity on heat transfer was found to be due to its impact on bubble behavior.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Nuclear Science & Technology
Orestes Castillo-Hernandez, P. E. Manuel Perdomo-Ojeda, C. R. Grantom, Pamela F. Nelson
Summary: Incorporating specified safety and production targets during the design phase can reduce costs and enhance the competitiveness of nuclear power plants. This paper presents two methods for proposing unavailability targets for nuclear reactor systems to optimize the design features. The methods are applied to a hypothetical facility, providing a basis for future work on estimating design alternatives affecting unavailabilities.
NUCLEAR ENGINEERING AND DESIGN
(2024)
Article
Nuclear Science & Technology
Qinjun Fu, Andre Bergeron, Philippe Fillion, Yohan Davit, Michel Quintard
Summary: In normal operating conditions, the flow within a pressurized water reactor (PWR) core primarily moves in the axial direction along the fuel rods. However, in accidents situations, transverse flows can have a significant impact on the thermal-hydraulic properties of the core. This study develops macroscopic pressure drop models for different flow directions and Reynolds numbers and validates them by comparing with existing system code results.
NUCLEAR ENGINEERING AND DESIGN
(2024)
Article
Nuclear Science & Technology
Xiang Chai, Xinyue Liu, Chaoran Guan, Tengfei Zhang, Xiaojing Liu
Summary: Micro nuclear reactors have gained attention for their high efficiency and long lifetime, making them suitable for remote and off-grid locations. This study examines the effects of burnable poisons on the performance of a micro nuclear reactor and improves the design for reactivity control. The computational results show that burnable poisons reduce excess reactivity and power peaking factor without significant impact on core lifetime.
NUCLEAR ENGINEERING AND DESIGN
(2024)
Article
Nuclear Science & Technology
Liwei Chen, Cong Zhou, Yu Wang, Yiran Zong, Tingting Lu, Chunhua Chen
Summary: This paper proposes an autonomous search method for leakage sources in nuclear emergency rescue based on the updated Infotaxis method. By considering factors such as radioactive decay and wet deposition, the method improves search efficiency and accuracy. Experimental results show that the method is particularly effective in searching for leakage sources under high emission rates and provides scientific information for early emergency response and consequence assessment.
NUCLEAR ENGINEERING AND DESIGN
(2024)
Article
Nuclear Science & Technology
Kirill S. Dolganov
Summary: This paper is the first part of a summary overview of IBRAE's work on the severe accident at Unit 1 of Fukushima Daiichi Nuclear Power Station. It focuses on the integral model of Unit 1 and its qualification with available data, including the comparison of simulation results with measurements for the initial phase of the accident. Important issues discussed include the direct modeling of isolation condenser performance and verification of the possibility to use an integral approach to estimate the nuclide inventory in the core.
NUCLEAR ENGINEERING AND DESIGN
(2024)
Article
Nuclear Science & Technology
F. Feria, C. Aguado, J. Benavides, J. Benavides, R. Canencia-Hernanz, M. Cristobal-Beneyto, J. Fernandez Garcia, H. Galan, C. Gonzalez, A. Hernandez-Avellaneda, L. E. Herranz, G. Jimenez, L. Martinez, J. C. Martinez-Murillo, A. Milena-Perez, A. Palacio Alonso, J. Penalva, R. Plaza, D. Perez-Gallego, L. Rey, N. Rodriguez-Villagra, J. Ruiz-Hervias, J. Saiz de Omenaca Tijero, P. Vinas-Pena
Summary: The Spanish R&D efforts in dry interim storage of spent nuclear fuel mainly focus on supporting safety under storage and transportation. Experimental and modelling activities are carried out to understand and predict the fuel response, with major outcomes being improvements in the characterization of dry stored fuel, essential for safety assessment of the back-end fuel cycle.
NUCLEAR ENGINEERING AND DESIGN
(2024)
Article
Nuclear Science & Technology
Ang Li, Yuqing Chen, Yuxian Rao, Qi Cai, Cong Wang
Summary: This paper focuses on the boiling heat transfer model of mini-channels casing-pipes once-through steam generator (MCOTSG). By calibrating and analyzing the different nucleate boiling heat transfer models based on steady state experimental results, the secondary loop heat transfer characteristics and overall operating characteristics of OTSG under feedwater flow rate reduction are simulated. The results can provide a basis for the safety analysis and optimal design of MCOTSG and small modular reactor under low flow rate conditions.
NUCLEAR ENGINEERING AND DESIGN
(2024)
Article
Nuclear Science & Technology
Shu Soma, Masahiro Ishigaki, Satoshi Abe, Yasuteru Sibamoto
Summary: In this paper, the analytical wall function approach was applied to analyze the condensation flow of steam/air mixtures, and good predictions were obtained through CFD analysis.
NUCLEAR ENGINEERING AND DESIGN
(2024)
Article
Nuclear Science & Technology
Jinho Song, Sungjoong Kim
Summary: In this study, a machine learning platform is proposed to assist operators in diagnosing the progression of severe accidents and predicting key parameters using long short term memory networks and MELCOR simulation data. The platform shows reasonable accuracy in predicting both similar and unseen test data, as well as lost signals and key parameters for accident management.
NUCLEAR ENGINEERING AND DESIGN
(2024)
Article
Nuclear Science & Technology
Liang Zhao, Zhengbai Chang, Chulin Mai, Hong Ran, Jin Jiang
Summary: This study investigates the dynamic characteristics, valve disc motion, and flow field of a nozzle check valve under different spring stiffness and fluid deceleration rates. Experimental tests and numerical simulations were performed to analyze the effects on various parameters during the dynamic closing process of the valve. The results provide insights for the optimization design of check valves and more accurate calculation of their dynamic characteristic curves.
NUCLEAR ENGINEERING AND DESIGN
(2024)
Article
Nuclear Science & Technology
Xun Lan, Yanbo Jiang, Dan Sun, Wenbo Liu, Wenjie Li
Summary: In this study, a three-dimensional phase-field model was developed to investigate the evolution of intergranular bubbles during irradiation. The study examined the dependency of bubble percolation on bubble shape, fission rate, and average grain size. The simulation results revealed the significant effects of these factors on the shape of GB bubbles, the percolation rate, and the connectivity threshold of GB bubbles.
NUCLEAR ENGINEERING AND DESIGN
(2024)
Article
Nuclear Science & Technology
J. M. S. Mendes, A. Heimlich, A. M. M. De Lima, F. C. Silva
Summary: An algorithm for solving the constitutive equations of the fourth-order Nodal Expansion Method (NEM) in parallel using GPU with quadratic transverse leakage has been proposed. The algorithm, implemented in CUDA language, showed comparable accuracy and reduced execution time compared to the CNFR code. This algorithm and the developed program have potential use in the optimization process of nuclear fuel reload patterns.
NUCLEAR ENGINEERING AND DESIGN
(2024)
Article
Nuclear Science & Technology
M. Jafari, H. Jafari, M. H. Choopan Dastjerdi, J. Mokhtari
Summary: This study investigates the ability of the PGNAA facility of the Isfahan MNSR reactor to measure boron concentration in solution samples. A measurement system model is developed using Monte Carlo calculation, and a cadmium sheet is used to reduce the effect of boron in the shield. The accuracy of the model is verified through experimental tests, resulting in a calibration curve.
NUCLEAR ENGINEERING AND DESIGN
(2024)
Article
Nuclear Science & Technology
Ibrahim Gad-el-Hak, Njuki Mureithi, Kostas Karazis, Brian Painter
Summary: This study investigates the risk of fluidelastic instability induced by degraded baffle-former bolts in a nuclear fuel assembly. Experimental results show that the stability threshold of the mock-up array strongly depends on the relative position of the jet flow with respect to the array centerline, and axial flow velocity also has a significant effect on the jet-induced instability.
NUCLEAR ENGINEERING AND DESIGN
(2024)
Article
Nuclear Science & Technology
Yuhang Niu, Scolaro Alessandro, Carlo Fiorina, Hao Qin, Gauthier Lazare, Yingwei Wu, Wenxi Tian, G. H. Su
Summary: This paper presents the incorporation of DNB prediction into the GeN-Foam code, which is based on OpenFOAM. The accuracy of GeN-Foam in modeling DNB conditions in PWR was assessed through validation against experimental data and other codes. The results show that GeN-Foam exhibits good performance in simulating two-phase flow boiling conditions and accurately predicts the occurrence of DNB.
NUCLEAR ENGINEERING AND DESIGN
(2024)
