Article
Thermodynamics
Jundi He, Wei Wang, Junjie Yan, Andrea Pucciarelli, Peixue Jiang, Walter Ambrosini, Shuisheng He
Summary: Fluid-to-fluid scaling is a widely applied method in experiments of supercritical fluid flows to reduce cost and technical difficulties. In this study, direct numerical simulations are used to assess a scaling scheme and establish further understanding of the conditions and parameters that determine the similarity in upward heated flows of supercritical fluids.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Sara Kassem, Andrea Pucciarelli, Walter Ambrosini
Summary: The study establishes a similarity theory for heat transfer at supercritical pressures, solving the problem of finding similar behavior between different fluids using original definitions. Further evidence from numerical simulations supports the theory's choices and comparisons of four different fluids under varying conditions.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Thermodynamics
Jiangtao Wang, Zhouhang Li, Yuling Zhai, Hua Wang
Summary: In this study, a two-phase numerical method was validated and optimized for heat transfer processes of supercritical fluids. The mixture model outperformed the volume of fluid model in predicting heat transfer deterioration (HTD) phenomena. The saturation temperature and condensation frequency were found to significantly impact the calculation results. The analysis revealed a link between the average gas volume fraction and HTD, and two types of pseudo-film boiling were identified in supercritical fluids.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
Alireza Rezvanpour, Ronald E. Miller
Summary: This work focuses on the journal bearing chamber of a gas turbine engine and explores the influence of rotor rotational speed on the velocity, pressure, and temperature distribution in the bulk oil. A CFD model and scaling analysis were used to verify and simplify the governing equations. The study confirmed the physical validity of the CFD model and demonstrated the effectiveness of scaling analysis in substituting experimental measurements to validate the simulation results.
THERMAL SCIENCE AND ENGINEERING PROGRESS
(2022)
Article
Thermodynamics
Kizuku Kurose, Naoto Watanabe, Kazushi Miyata, Hideo Mori, Yoshinori Hamamoto, Shuichi Umezawa
Summary: A computational fluid dynamics model was developed to predict the cooling heat transfer coefficient and pressure drop of supercritical pressure refrigerants in a chevron-type PHE, with good agreement with experimental results. The model can be applied to existing and new refrigerants, as well as used to optimize the plate shape of chevron-type PHEs. Discussions on flow behavior and heat transfer characteristics of refrigerants in the PHE were based on simulation results.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Thermodynamics
Krishnamoorthy Viswanathan, Gautham Krishnamoorthy
Summary: This study uses numerical simulations to demonstrate that heat transfer of supercritical CO2 under constant wall heat flux conditions is significantly influenced by the magnitude of the imposed heat flux, while being independent of the inlet Reynolds number.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2021)
Article
Thermodynamics
Kwun Ting Lau, Shahid Ali Khan, Chika Eze, Bing Tan, Jiyun Zhao
Summary: This study numerically investigates the effect of tubes with variable cross-sectional geometries on the deteriorated heat transfer of upward flow supercritical water. It is found that converging channels can suppress and delay the heat transfer deterioration, while diverging channels have the opposite effect. Periodic geometries, with alternating convergent and divergent sections, can alleviate the heat transfer deterioration with minimal pressure drop.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2022)
Article
Nuclear Science & Technology
Andrea Pucciarelli, Walter Ambrosini
Summary: This paper presents a novel approach to predicting deteriorated heat transfer to supercritical pressure fluids. By considering the experimental trends and using CFD RANS models, the study interprets the effects of flow laminarization as a form of entry length problem applicable to supercritical pressure fluids. The prediction of these effects is addressed using an iterative procedure based on observed trends of Nusselt number and wall temperature. The methodology may have practical implications for predicting heat transfer deterioration in supercritical water nuclear reactor conditions.
NUCLEAR ENGINEERING AND DESIGN
(2022)
Article
Thermodynamics
Haisong Zhang, Jinliang Xu, Qingyang Wang
Summary: Supercritical fluids are widely used in power generation systems and the heat transfer deterioration phenomenon is of great importance to their design and operation. However, there is a lack of quantitative models to determine the position of the wall temperature peak during heat transfer deterioration and accurately predict the characteristics. In this study, two correlations were developed based on experimental results for supercritical CO2 in vertical upward tubes. These correlations provide quantitative models for the heat transfer deterioration phenomenon and can benefit the engineering application of supercritical power cycles.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Engineering, Chemical
Tianning Zhang, Youjun Lu
Summary: This paper investigates the heat transfer characteristics between the wall and bed in SCWFB, comparing the accuracy of different methods in predicting heat transfer coefficients, and studying the influence of factors such as temperature, pressure, and velocity on heat transfer characteristics.
Article
Thermodynamics
Fatih Demir, Oguz Turgut, Tamer Calisir
Summary: The flow field and heat transfer of a swirling jet under low nozzle-to-plate distances were numerically investigated using various turbulence models. The effects of Reynolds number and dimensionless nozzle-to-plate distance on the flow field and heat transfer were analyzed. The results showed that the height of the computational domain defined on the impingement plate significantly influenced the results, particularly at low nozzle-to-plate distances. The agreement between one of the cases and experimental results was observed when using the Realizable k-e turbulence model. The parametric analysis revealed that the theoretical swirl number decreased as Reynolds number increased at a constant nozzle-to-plate distance, but increased for nozzle-to-plate distances below 0.75. The pressure peaks and subatmospheric pressure on the impingement plate varied with the nozzle-to-plate distance and Reynolds number.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2023)
Article
Thermodynamics
D. J. Cerantola, P. Gareau, A. Hutchison, C. D. Lane
Summary: This paper presents a study on rock pile heat exchangers, validating a numerical methodology and proposing guidelines for improving performance. It suggests that increasing pile flatness and hemispericality can benefit damping and phase shifting, respectively. A case study shows that a rock pile constructed using traditional methods can achieve good damping with a pressure penalty.
APPLIED THERMAL ENGINEERING
(2022)
Article
Thermodynamics
R. Siddharth, Shaik Subhani, Rajendran Senthil Kumar
Summary: The study investigates the flow and heat transfer characteristics of two hot circular bodies in a 2D simulation. By optimizing the geometry, maximum heat dissipation can be achieved. The positioning of the cylinders in the enclosure has a significant impact on heat transfer rate.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2022)
Review
Nuclear Science & Technology
Gaurav Kumar, Raj Kumar Singh
Summary: This review article provides a comprehensive understanding of the heat transfer features of supercritical water in tubes with wire-wrapped rod bundles. It discusses the effects of supercritical pressure, thermo-physical properties of water, and relevant parametric effects on heat transfer performance. The challenges of turbulence models and the simulation of buoyancy and turbulent heat flux are highlighted.
PROGRESS IN NUCLEAR ENERGY
(2023)
Article
Thermodynamics
Jian Wang, Xin-ping Yan, Bendiks J. Boersma, Ming-jian Lu, Xiaohua Liu
Summary: Printed circuit heat exchangers (PCHE) are proposed to improve heat recovery and energy saving in supercritical CO2 (S-CO2) power cycles. A modified channel PCHE is investigated to enhance the thermal-hydraulic performance. The results show that the inserted straight section reduces pressure loss and improves flow uniformity, leading to a significant improvement in performance.
APPLIED THERMAL ENGINEERING
(2023)
Article
Nuclear Science & Technology
F. Galleni, G. Barone, D. Martelli, A. Pucciarelli, P. Lorusso, M. Tarantino, N. Forgione
NUCLEAR ENGINEERING AND DESIGN
(2020)
Article
Nuclear Science & Technology
F. Buzzi, A. Pucciarelli, F. Galleni, M. Tarantino, N. Forgione
ANNALS OF NUCLEAR ENERGY
(2020)
Article
Thermodynamics
Andrea Pucciarelli, Shuisheng He, Walter Ambrosini
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2020)
Article
Thermodynamics
Andrea Pucciarelli, Walter Ambrosini
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2020)
Article
Chemistry, Multidisciplinary
Pucciarelli Andrea, Galleni Francesco, Moscardini Marigrazia, Martelli Daniele, Forgione Nicola
APPLIED SCIENCES-BASEL
(2020)
Article
Chemistry, Multidisciplinary
Moscardini Marigrazia, Galleni Francesco, Pucciarelli Andrea, Martelli Daniele, Forgione Nicola
APPLIED SCIENCES-BASEL
(2020)
Article
Nuclear Science & Technology
A. Pucciarelli, F. Galleni, M. Moscardini, D. Martelli, N. Forgione
NUCLEAR ENGINEERING AND DESIGN
(2020)
Article
Nuclear Science & Technology
A. Pucciarelli, A. Toti, D. Castelliti, F. Belloni, K. Van Tichelen, M. Moscardini, F. Galleni, N. Forgione
Summary: This article reviews the general guidelines for conducting coupled System Thermal Hydraulics (STH)/CFD calculations, discussing the necessity and advantages of coupled analysis, analyzing different coupling methods and application fields, and summarizing a set of good practice guidelines.
ANNALS OF NUCLEAR ENERGY
(2021)
Article
Thermodynamics
Sara Kassem, Andrea Pucciarelli, Walter Ambrosini
Summary: The study establishes a similarity theory for heat transfer at supercritical pressures, solving the problem of finding similar behavior between different fluids using original definitions. Further evidence from numerical simulations supports the theory's choices and comparisons of four different fluids under varying conditions.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Energy & Fuels
Andrea Pucciarelli, Sara Kassem, Walter Ambrosini
Summary: Recent advancements in the development of a fluid-to-fluid similarity theory for heat transfer with fluids at supercritical pressures are summarized, with a focus on the application in Supercritical Water nuclear Reactors. The developed rationale, based on a specific definition of similarity, aims to achieve similar distributions of enthalpies and fluid densities in a duct containing fluids at supercritical pressure, providing assurance for representing complex heat transfer phenomena. The theory can be used for planning experiments and setting up correlations for heat transfer in different regimes, enhancing our understanding and predictive capabilities in this challenging area.
Article
Nuclear Science & Technology
M. Moscardini, F. Galleni, A. Pucciarelli, M. Eboli, A. Del Nevo, S. Paci, N. Forgione
Summary: The study aims to develop a numerical model to simulate the thermo-hydraulic behavior of the PbLi ancillary system under normal operation and accidental scenarios, investigating the propagation of pressure waves resulting from an in-box LOCA.
FUSION ENGINEERING AND DESIGN
(2021)
Article
Energy & Fuels
Francesco Galleni, Marigrazia Moscardini, Andrea Pucciarelli, Maria Teresa Porfiri, Nicola Forgione
Summary: This work presents a thermohydraulic analysis of a postulated accident involving the rupture of the breeder primary cooling loop inside a heat exchanger. The results show that the pressures and temperatures inside the whole system remain below the safety thresholds for the whole transient, demonstrating effective control of the system throughout the entire transition.
Article
Thermodynamics
Jundi He, Wei Wang, Junjie Yan, Andrea Pucciarelli, Peixue Jiang, Walter Ambrosini, Shuisheng He
Summary: Fluid-to-fluid scaling is a widely applied method in experiments of supercritical fluid flows to reduce cost and technical difficulties. In this study, direct numerical simulations are used to assess a scaling scheme and establish further understanding of the conditions and parameters that determine the similarity in upward heated flows of supercritical fluids.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Nuclear Science & Technology
Andrea Pucciarelli, Afaque Shams, Nicola Forgione
Summary: The present paper investigates the capabilities of selected RANS turbulence models in reproducing DNS data for liquid metals thermal hydraulics. Forced and mixed convection conditions, addressing buoyancy-aided and buoyancy-opposed flow, are considered. The paper focuses on velocity and temperature fields estimation, comparing RANS and DNS computations. The results show that the AHFM model provides better predictions for the phenomena considered, particularly for temperature fields, supporting its use as a valuable tool for predicting turbulent heat fluxes.
ANNALS OF NUCLEAR ENERGY
(2023)
Article
Nuclear Science & Technology
S. Kassem, A. Pucciarelli, W. Ambrosini
Summary: In this paper, the authors use a low-Reynolds number turbulence model to predict heat transfer at supercritical pressure with different degrees of surface finishing. The model is able to reproduce friction factors and is based on a simple description of the effect of wall protrusions on turbulence production in the boundary layer. Sensitivity analysis is conducted to characterize the predictions at different roughness parameter values, especially with respect to the possibility of suppressing deteriorated heat transfer by roughened surfaces. Experimental data on carbon dioxide are used to validate the model's capability to predict wall temperature values with different boundary conditions. The described model shows promise not only in predicting experimentally measured effects, but also in studying the behavior of purposely roughened surfaces to reduce the occurrence of deteriorated heat transfer.
ANNALS OF NUCLEAR ENERGY
(2023)
Article
Nuclear Science & Technology
Kecheng Jiang, Jinzhao Yang, Xueli Zhao, Lei Chen, Fujun Gou, Songlin Liu
Summary: The blanket, as a key component of the fusion reactor, plays important roles in breeding tritium, shielding neutrons, and extracting thermal energy for electricity generation. Understanding the characteristics of gas-liquid two-phase flow and mass transfer is essential for optimizing the design of tritium extraction units in the blanket.
ANNALS OF NUCLEAR ENERGY
(2024)
Article
Nuclear Science & Technology
Anna-Elina Pasi, Teemu Karkela, Fredrik Borjesson Sanden, Unto Tapper, Tuula Kajolinna, Christian Ekberg
Summary: This study investigates the gas-phase interactions between tellurium and organic material under severe nuclear accident conditions. The results show that there is interaction between tellurium aerosols and organic material, leading to an increase in the gaseous fraction and changes in XPS spectra. Although the exact species are not identified, these findings raise questions about the behavior of tellurium and its reactions with organic material in severe accident conditions.
ANNALS OF NUCLEAR ENERGY
(2024)
Article
Nuclear Science & Technology
Ao Zhang, Qingye Li, Chaoyong Zong, Fuwen Liu, Tianhang Xue, Jian Xiao, Xueguan Song
Summary: In this study, a high-fidelity computational fluid dynamics model was established to investigate the flow characteristics of a novel balanced globe valve. The study found that the size of the throttle orifice and valve disc displacement have a significant impact on fluid force. The findings provide a basis for the design and dynamic control of globe valves, and also have potential value for energy utilization.
ANNALS OF NUCLEAR ENERGY
(2024)
Article
Nuclear Science & Technology
Wenbo Li, Yunqing Bai, Shuai Zhang, Yang Li, Ming Jin, Chunjing Li
Summary: In this study, a 3D-CFD model based on the SUPERCAVNA facility was established to analyze thermal stratification in liquid-metal-cooled nuclear reactors. The results show that the SKE model is the most accurate in predicting temperature distribution, and further parametric studies were conducted.
ANNALS OF NUCLEAR ENERGY
(2024)
Article
Nuclear Science & Technology
Song Jin, Di Jiang, Dongmei Wang, Shaojie Wang, Zhen Wang
Summary: This study presents the fragility evaluation of a nuclear containment structure subjected to earthquake and subsequent internal pressure sequence. Nonlinear finite element model and ground motion records are used to analyze the nonlinear response and fragility of the structure. Results show that the distribution of maximum strain and displacement of the structure under earthquake and subsequent pressure are significantly different, with displacement distribution related to ground motion intensity levels.
ANNALS OF NUCLEAR ENERGY
(2024)
Article
Nuclear Science & Technology
Kazumasa Shimada, Tatsuya Sakurahara, Pegah Farshadmanesh, Seyed Reihani, Zahra Mohaghegh
Summary: This research improves the realism of Level 3 probabilistic risk assessment for nuclear power plants by modeling the evacuation behavior of residents and incorporating two advancements. The first advancement uses evacuation speed from a transportation simulation code as input to the Level 3 PRA code, enabling explicit incorporation of spatiotemporal evacuation processes. The second advancement incorporates the probability of seismic damage to roadway bridges into Level 3 PRA and calculates evacuation routes and speeds considering the impact of seismic damage.
ANNALS OF NUCLEAR ENERGY
(2024)
Article
Nuclear Science & Technology
F. Mascari, A. Bersano, M. Massone, G. Agnello, O. Coindreau, S. Beck, L. Tiborcz, S. Paci, M. Angelucci, L. E. Herranz, R. Bocanegra, Y. Pontillon, M. Berdai, O. Cherednichenko, A. Iskra, M. Nudi, P. Groudev, P. Petrova, F. Kretzschmar, F. Gabrielli, Z. Kanglong, V. Vileiniskis, T. Kaliatka, J. Kalilainen, M. Malicki, D. Gumenyuk, Y. Vorobyov, O. Kotsuba, P. Dejardin, M. Di Giuli, R. Thomas, I. V. Ivanov, F. Giannetti, M. D'Onorio, G. Caruso, M. Salay, T. Sevon
Summary: The MUSA project aims to analyze uncertainties and sensitivities associated with severe accidents using a harmonized approach, particularly focusing on source term figures of merit. The project applied and tested uncertainty quantification methodologies using the PHEBUS FPT1 test. The study found that scripting for coupling SA codes and uncertainty tools can increase flexibility, and careful consideration should be given to selecting the input uncertain parameters.
ANNALS OF NUCLEAR ENERGY
(2024)
Article
Nuclear Science & Technology
Ian Greenquist, Nathan Capps
Summary: The US nuclear energy industry is investigating strategies to increase reactor operating cycle to 24 months. Multiphysics simulations tools and methodologies are being developed to predict the effects of this change during transient events such as loss-of-coolant accidents (LOCAs).
ANNALS OF NUCLEAR ENERGY
(2024)
Article
Nuclear Science & Technology
Guangchun Zhang, Hu Zhang
Summary: In this study, a neutron transport code called TARS is introduced, which is based on the discrete-ordinates discontinuous finite element method. TARS provides accurate and efficient solutions to the neutron transport equation, addressing existing challenges in the field. The evaluation results demonstrate that TARS generates highly accurate solutions and achieves high parallel computation efficiency.
ANNALS OF NUCLEAR ENERGY
(2024)
Article
Nuclear Science & Technology
J. R. Daniels, M. M. R. Williams, M. D. Eaton
Summary: This paper presents the development and verification of a collision probability (CP) code for neutron transport in slabs and cylinders. The CP code is particularly useful for modelling layered systems of aqueous and organic plutonium nitrate. The code provides a computationally inexpensive alternative to higher fidelity codes like MCNP. It is effective for slab geometries with at least 0.7 g cm-2 plutonium, but its approximation for heterogeneous cylinders can lead to overestimation of neutron leakage. Increasing the cylinder radius to 40.0 cm improves the accuracy for systems with at least 2.75 kg plutonium. However, the code's accuracy decreases when modelling cylindrical geometries with dished ends and low plutonium content.
ANNALS OF NUCLEAR ENERGY
(2024)
Article
Nuclear Science & Technology
Alexander A. Ryzhkov, Georgy V. Tikhomirov, Mikhail Yu. Ternovykh
Summary: This paper analyzes the impact of nuclear data uncertainties on the safety of advanced reactors, with a specific focus on angular distribution uncertainties. Through sensitivity and uncertainty analysis, key parameters for MOX3600 are identified, and a comparison of different libraries' uncertainties on the eigenvalue is performed.
ANNALS OF NUCLEAR ENERGY
(2024)
Article
Nuclear Science & Technology
Y. Fontenla, A. Vidal-Ferrandiz, A. Carreno, D. Ginestar, G. Verdu
Summary: FEMFFUSION is an open source code that solves the multigroup neutron transport equation using the diffusion and the SPN approximations. It uses the finite element method to handle various geometries and problem dimensions, and has been verified against the C5G7 benchmark.
ANNALS OF NUCLEAR ENERGY
(2024)
Article
Nuclear Science & Technology
J. Tyler Gates, Pavel V. Tsvetkov
Summary: The Optical Fiber Based Gamma Thermometer utilizes optical fiber as a distributed temperature sensor to measure the temperature of a thermal mass undergoing gamma heating and calculate the gamma flux data. This technology shows promise in determining the local power density within a nuclear reactor core and provides an unparalleled level of precision in reactor power measurement.
ANNALS OF NUCLEAR ENERGY
(2024)
Article
Nuclear Science & Technology
A. de Lara, A. Schubert, E. Shwageraus, P. Van Uffelen
Summary: This study presents a new methodology to derive the radial form factor in the TRANSURANUS burnup model using simulations. The proposed methodology can be applied to different types of reactors, including LWRs and HWRs, and is suitable for advanced technology fuels.
ANNALS OF NUCLEAR ENERGY
(2024)
Article
Nuclear Science & Technology
A. Bousbia Salah, M. Di Giuli, P. Foucaud, R. Iglesias, A. Malkhasyan, M. Salmaoui, L. E. Herranz
Summary: In the framework of the R2CA project, the application of advanced codes for evaluating radiological release under design basis accidents was considered. The study focused on a specific scenario and assessed the results obtained by different organizations using different computational tools and approaches. The outcomes highlighted modeling differences and challenges in carrying out such analysis.
ANNALS OF NUCLEAR ENERGY
(2024)