Article
Mechanics
Fangcheng Shi, Zhenxun Gao, Chongwen Jiang, Chun-Hian Lee
Summary: This paper conducts direct numerical simulation of shock-turbulent mixing layer interaction to investigate the influence of shock-turbulent interaction on turbulence evolution and shock-associated noise. The results show changes in turbulent kinetic energy, pressure fluctuation, and Reynolds-stress anisotropy, as well as an increase in shock-associated noise level and high-frequency noise. The study identifies two generation mechanisms of shock-associated noise and explores the impact of shock strength on noise reduction.
Article
Mechanics
Emmanuel Hitimana, Rodney O. Fox, James C. Hill, Michael G. Olsen
Summary: This study investigates the coherent structures of turbulent swirling flow within the multi-inlet vortex reactor, revealing elliptical shapes of velocity and concentration fluctuations with positive correlations near basepoints and surrounded by negatively correlated regions. Linear stochastic estimation shows obliquely oriented counter-rotating vortical structures that depend on local concentration gradient.
Article
Nuclear Science & Technology
Angel Papukchiev, Zhi Yang
Summary: The trend in thermal-hydraulic codes is to couple them with computational fluid dynamics tools, and the validation of coupled 1D-3D numerical codes has received strong attention in international projects in recent years. By comparing with experimental data, the simulation results of different codes can be validated.
PROGRESS IN NUCLEAR ENERGY
(2021)
Article
Chemistry, Multidisciplinary
Yudong Li, Li Chen, Hongxun Li, Yungang Wu, Shuang Chen
Summary: The design of a supersonic-supersonic mixing layer facility was motivated by the need for a benchmark experimental platform to study the physical phenomena underlying supersonic mixing layers. The facility was calibrated and optical diagnosis measurements were performed to validate the experimental data, and large-eddy simulation was conducted to provide a comprehensive view of the flow field.
APPLIED SCIENCES-BASEL
(2022)
Article
Mechanics
Tie Wei, Zhaorui Li, Daniel Livescu
Summary: Proper scales for the mean flow and Reynolds shear stress in planar turbulent mixing layers are determined and self-similar equations are derived in this study. The derived equations are found to agree well with experimental data.
Article
Mechanics
Gen Wu, Le Fang, Jin Zhang
Summary: This paper introduces a new synthetic turbulence method called AEM and applies it to generate inlet conditions in the open-source software code_saturne. By comparing with direct numerical simulation and synthetic eddy method, the ability of AEM to accurately predict turbulent kinetic energy profiles is validated. Parametric analysis is also conducted to discuss the specific effect of each factor.
Article
Engineering, Aerospace
Jaewon Lee, Sang Gon Lee, Sang Hun Kang, Hyuck-Joon Namkoung
Summary: In this study, the flow characteristics of non-oscillatory unstarted flow in a scramjet inlet-isolator model are investigated using numerical analysis. It is found that the direction-changing processes within the boundary layers and the recirculation zones near the rear part of the model irregularly influence the non-oscillatory unstarted flow.
Article
Mechanics
Joseph Amponsah, Pius Ohene Darko
Summary: This study investigates the radial velocity profiles near the impeller tip in a baffled stirred tank through experimental measurements and computational fluid dynamics (CFD) simulations. The results show that double turbine impellers generate localized turbulence, while pitched blade turbines with down-pumping produce high-intensity turbulence zones throughout the tank. The CFD simulations align closely with experimental data and provide further insight into flow patterns.
Article
Mechanics
Zhaomiao Liu, Kai Shi, Fanming Cai, Yanlin Ren
Summary: In this paper, the ternary dilute solute lattice Boltzmann model is used to study the mixing processes and mechanisms of solutes inside Janus droplets. The results show that there is a main circulation and a dead zone inside the droplet, and the mixing efficiency is affected by factors such as droplet velocity, tilt angle, and volume ratio. This study provides theoretical support for further improvement of droplet micro-mixer efficiency.
Article
Biotechnology & Applied Microbiology
Soroush Dabiri, Johannes Sappl, Prashant Kumar, Michael Meister, Wolfgang Rauch
Summary: Sludge recirculation mixing is crucial for the stable operation of anaerobic digesters, with the configuration of the sludge inlet significantly influencing process efficiency. Computational fluid dynamics was used to investigate the effect of inlet configuration, with single-phase and multi-phase models applied for submerged and splashing inlets. A surrogate single-phase model was developed to reduce computational demand, showing promising results in terms of reducing dead volume and simulation clock time.
BIOPROCESS AND BIOSYSTEMS ENGINEERING
(2021)
Article
Thermodynamics
Cenk Evrim, Eckart Laurien
Summary: This study presents wall-resolved Large-Eddy Simulations of thermal mixing mechanisms in both horizontal and vertical T-junctions. The influence of the inflowing cold water stream on the mixing mechanism in various T-junction configurations is investigated, showing a stable stratification in the horizontal configuration may transform into an unstable stratified flow behavior in the vertical configuration. Additionally, a spectral analysis of the fluid temperature signal near the piping material reveals good agreement between predicted LES results and experimental data.
APPLIED THERMAL ENGINEERING
(2021)
Article
Energy & Fuels
Yanwen Gong, Xueni Cheng
Summary: Electroosmotic micromixing is a valuable technique in microanalysis systems, and a contraction-expansion microchannel is used to study the mixing caused by AC electroosmotic. The flow and concentration field distributions in the microchannel are analyzed, and the influence of AC electric fields on circulation flows and rotating vortices is observed. The study shows that the mixing quality is dependent on the relative magnitudes of the electroosmotic force and inertia force, and factors such as inlet velocity, frequency, and voltage also affect the vortex formation and mixing performance.
CHEMICAL ENGINEERING AND PROCESSING-PROCESS INTENSIFICATION
(2023)
Article
Mechanics
R. Boukharfane, A. Er-raiy, M. Elkarii, M. Parsani
Summary: This study systematically investigates the turbulent flow of spatially developing and high-speed hydrogen/air mixing layers subject to small skew angle ζ using direct numerical simulation. The analysis reveals that skewing leads to faster growth of the inlet structures, enhancing mixing in the process. Through transport equations of Reynolds stresses, the underlying mechanisms responsible for turbulence modulation are analyzed.
Article
Multidisciplinary Sciences
Aamir Ali, Tasmia Kanwal, Muhammad Awais, Zahir Shah, Poom Kumam, Phatiphat Thounthong
Summary: The study investigates the impacts of thermal radiations and non-uniform heat flux on magnetohydrodynamic hybrid nanofluid flow along a stretching cylinder. By using numerical methods, changes in velocity and temperature fields are analyzed. Results show that adding hybrid nanofluid particles decreases fluid velocity but increases temperature, while considering magnetic field and slip effects also leads to a decrease in fluid velocity.
SCIENTIFIC REPORTS
(2021)
Article
Engineering, Aerospace
Yilun Yan, Jiangfeng Wang
Summary: This study investigates the use of active flow control using nanosecond surface dielectric barrier discharge (NS-SDBD) as a solution to the performance decline of a scramjet inlet in off-design mode. The results show that NS-SDBD actuators can increase static pressure and total pressure, providing a numerical basis for the control of a hypersonic inlet.
Article
Nuclear Science & Technology
A. Kovtonyuk, S. Lutsanych, F. Moretti, F. D'Auria
NUCLEAR ENGINEERING AND DESIGN
(2017)
Article
Nuclear Science & Technology
S. Lutsanych, F. Moretti, F. D'Auria
NUCLEAR ENGINEERING AND DESIGN
(2017)
Article
Nuclear Science & Technology
S. Lutsanych, F. Moretti, F. D'Auria
NUCLEAR ENGINEERING AND DESIGN
(2017)
Article
Nuclear Science & Technology
A. Bucalossi, A. Del Nevo, F. Moretti, F. D'Auria, I. V. Elkin, O. I. Melikhov
NUCLEAR ENGINEERING AND DESIGN
(2012)
Article
Nuclear Science & Technology
F. Moretti, D. Melideo, A. Del Nevo, F. D'Auria, T. Hoehne, E. Lisenkov
SCIENCE AND TECHNOLOGY OF NUCLEAR INSTALLATIONS
(2009)
Article
Nuclear Science & Technology
Maria Cristina Galassi, Pierre Coste, Christophe Morel, Fabio Moretti
SCIENCE AND TECHNOLOGY OF NUCLEAR INSTALLATIONS
(2009)
Review
Nuclear Science & Technology
D. Bestion, H. Anglart, D. Caraghiaur, P. Peturaud, B. Smith, M. Andreani, B. Niceno, E. Krepper, D. Lucas, F. Moretti, M. C. Galassi, J. Macek, L. Vyskocil, B. Koncar, G. Hazi
SCIENCE AND TECHNOLOGY OF NUCLEAR INSTALLATIONS
(2009)
Article
Nuclear Science & Technology
Dino Araneo, Paolo Ferrara, Fabio Moretti, Andrea Rossi, Andrea Latini, Francesco D'Auria, Oscar A. Mazzantini
SCIENCE AND TECHNOLOGY OF NUCLEAR INSTALLATIONS
(2011)
Article
Nuclear Science & Technology
A. Del Nevo, D. Rozzia, F. Moretti, F. D'Auria
SCIENCE AND TECHNOLOGY OF NUCLEAR INSTALLATIONS
(2012)
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)
