Article
Thermodynamics
Ni Li, Hang Pu, Lin Zhou, Hangchen Qu, Yining Zhang, Ming Dong
Summary: This study investigates the influence of buoyancy force on heat transfer to supercritical carbon dioxide flowing in horizontal minichannels. Numerical simulations are conducted to analyze the heat transfer mechanism in different channels and the effect of heat flux. It is found that the heat transfer in the bottom wall is stronger than that in the top wall due to the buoyancy force. The study also evaluates the applicability of three existing buoyancy parameters and identifies the BuP buoyancy criterion as the most accurate. Above a certain threshold value, natural convection significantly affects forced turbulent heat transfer.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
Xiao-jing Zhu, Rui-zeng Zhang, Xin Du, Xiao Yu, Qing-gang Qiu
Summary: An experimental investigation on heat transfer in vertical upward supercritical CO2 flow was conducted, and correlations and buoyancy parameters were evaluated based on the experimental data. A segmented correlation considering buoyancy was proposed to predict the heat transfer behavior.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Han Wang, Shunqi Wang, Jinguang Zang, Junfeng Wang, Yanping Huang
Summary: Direct numerical simulation was used to study the heat transfer of SCO2 in a semicircular pipe under mixed and forced convection. The study revealed significant effects of secondary flow, thermal acceleration, corner effect, and geometric orientation on heat transfer.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Thermodynamics
Xiaocheng Du, Yuanyuan Song, Yanjun Zhou, Yuxuan Xiang, Aoyu Wang, Dong Yang
Summary: The influence of varying buoyancy effects on heat transfer characteristics was investigated experimentally and numerically. Different operating parameters were used to alter the buoyancy effect, and comparisons were made to analyze the heat transfer characteristics. A 3-D numerical model was also built to predict the heat transfer characteristics in inclined tubes, and the influence of buoyancy effects induced by different inclination angles was investigated numerically.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Dingchen Wu, Mingshan Wei, Jundi He, Shuisheng He, Ran Tian
Summary: This paper investigates the flow and heat transfer mechanisms of supercritical carbon dioxide in the supercritical CO2 Brayton Cycle coupled with solar energy under cooling conditions using direct numerical simulation. The effects of property variation, buoyancy, and thermal deceleration under different flow conditions are studied. Buoyancy plays a dominant role in upward flow, enhancing heat transfer, while in downward flow, buoyancy leads to flow laminarization and heat transfer deterioration. Heat transfer recovery is purely due to the increase in turbulence components.
APPLIED THERMAL ENGINEERING
(2023)
Article
Nuclear Science & Technology
Tanuj Srivastava, Dipankar N. Basu
Summary: The thermalhydraulics of a supercritical natural circulation loop (sNCL) are heavily influenced by the operating conditions and geometric configurations chosen. This study focuses on the identification of a quantifiable criterion for the deterioration in a rectangular loop driven by carbon dioxide. The study identifies four operation regimes based on temperature levels and suggests operating within the enhanced heat transfer regime for better heat transfer. The study also observed the impact of loop inclination on circulation rate and heat transfer deterioration, as well as proposing a buoyancy parameter to predict the appearance of deterioration.
NUCLEAR ENGINEERING AND DESIGN
(2022)
Article
Thermodynamics
Zhengming Yi, Yong Xu, Xiaolin Chen
Summary: This study investigates the effects of mass flux and heat flux on heat transfer in a vertical serpentine micro-tube, as well as the different influences of buoyancy and centrifugal force in the liquid-like and gas-like regions. The results show that the heat transfer coefficient decreases with increasing heat flux and increases with increasing mass flux. The liquid-like region is more affected by buoyancy, resulting in significant differences between upward and downward flow heat transfer coefficients, while the gas-like region is less affected, with smaller differences between the coefficients. At the turning point of the micro-tube, centrifugal force weakens heat transfer, with a larger effect in the liquid-like region. These findings provide important insights into the effects of buoyancy and centrifugal force on flow and heat transfer in different regions.
APPLIED THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Jingzhe Xie, Gongnan Xie
Summary: The present study reproduces the direct numerical simulation (DNS) of supercritical carbon dioxide flow in heated circular tubes using large eddy simulation (LES). The simulation captures heat transfer deterioration and recovery, and shows excellent agreement with DNS data. Buoyancy effect, mean flow characteristics, and turbulence statistics are analyzed for different conditions. LES is found to be a reliable and feasible means to explore supercritical heat transfer, considering the significant cost of DNS in terms of computing resources and time consumption.
INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW
(2022)
Article
Thermodynamics
Xinxin Liu, Xiaoxiao Xu, Youzhou Jiao, Chao He, Liang Liu, Chaobin Dang
Summary: The study investigates the mixed turbulent convection heat-transfer characteristics of S-CO2 heated in both vertical and horizontal oriented HC-tube, finding that the coupling effects of buoyancy and centrifugal forces mainly affect heat transfer on the inside of a cross-section and the M-type velocity pattern in HC-tube is different from that in straight tube.
APPLIED THERMAL ENGINEERING
(2021)
Article
Nuclear Science & Technology
Pengfei Wang, Peng Ding, Wenhuai Li, Rongshun Xie, Chengjie Duan, Gang Hong, Yaoli Zhang
Summary: An experimental study on the heat transfer characteristics of supercritical carbon dioxide (sCO(2)) uniformly heated in a horizontal circular smooth tube was conducted. The study found that there was a significant difference in heat transfer between the top wall and bottom wall due to buoyancy. Bulk flow acceleration in the high heat flux region was found to cause heat transfer deterioration. A new heat transfer correlation that accounted for the buoyancy parameter and bulk flow acceleration was proposed. The comparison of the new correlation and six classic correlations showed that the new correlation performed better for sCO(2) flowing through a horizontal heating tube under natural circulation conditions.
NUCLEAR ENGINEERING AND TECHNOLOGY
(2022)
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
Energy & Fuels
Litao Zhou, Hong Xu, Yaoli Zhang, Gang Hong
Summary: This paper presents a numerical simulation of Rayleigh-Benard convection with supercritical carbon dioxide. A shallow cavity with an aspect ratio of 4 is selected as the container which is fully filled with supercritical carbon dioxide. The influences of the bottom heat flux on the stability, flow pattern evolution, and heat transfer ability of the convection are analyzed. The results show that the bottom heat flux plays a dominating role in the stability of the convection, and a transition from stable evolution to significant oscillation is observed with the increase of heat flux.
FRONTIERS IN ENERGY RESEARCH
(2023)
Article
Thermodynamics
Feng Jin, Deqi Chen, Lian Hu, Yanping Huang, Shanshan Bu
Summary: This paper investigates the flow distribution and thermohydraulic characteristics of printed circuit heat exchanger (PCHE) with different channel configurations. It is found that PCHE with larger flow resistance in the core region shows better flow uniformity and heat transfer performance. A modified manifold with bent fins and airfoil fins is proposed to improve the flow maldistribution of PCHE, reducing the flow non-uniformity by 39.4% to 61.8% and increasing the overall performance by 5% to 8.5% compared to the original manifold.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Shunqi Wang, Han Wang, Jinguang Zang, Junfeng Wang, Yanping Huang
Summary: This study numerically investigated the turbulent flow and heat transfer of SCO2 in a rod bundle, focusing on the effects of wire shape, wire pitch, and number of wire thread on heat transfer and pressure drop. It was found that the trapezoid-shaped wire showed the best performance among different wire shapes.
APPLIED THERMAL ENGINEERING
(2021)
Article
Thermodynamics
Shaogeng Zhong, Yan Ren, Weidong Wu, Yingying Yang, Qiguo Yang
Summary: In this study, a mathematic-physical model was established to investigate the local heat transfer characteristics of supercritical CO2 in semicircular and circular channels under cooling condition. The model was validated with experimental data, yielding a maximum error of 12.44%. The results showed that the local heat transfer coefficient of SCO2 exhibited an initial increase and then a decrease along the flow direction, regardless of the channel shape. The heat transfer performance of the horizontal semicircular channel was weaker than that of the circular channel due to the influence of buoyancy effect. A heat transfer correlation for the supercritical CO2 cooling process in the horizontal semicircular channel was modified by considering the influence of the dimensionless buoyancy effect and hydraulic diameter, yielding prediction errors within +/- 13.5%.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Review
Nanoscience & Nanotechnology
Yuxiu Li, Jinliang Xu, Dongqing Li
MICROFLUIDICS AND NANOFLUIDICS
(2010)
Article
Engineering, Chemical
Yuxiu Li, Shashank S. Tiwari, Geoffrey M. Evans, Krishnaswamy Nandakumar, Jyeshtharaj B. Joshi
Summary: Direct Numerical Simulations (DNS) using a non-Lagrangian multiplier based fictitious domain (FD) method were conducted to study the behavior of freely falling/rising rigid particles in a quiescent fluid. The simulations validated well against experimental results and identified several distinct flow regimes, including helical and zig-zagging trajectories for different solid-to-fluid density ratios. Fast Fourier Transform (FFT) analysis revealed a bimodal frequency pattern similar to flow past an isolated stationary bluff body.
INTERNATIONAL JOURNAL OF CHEMICAL REACTOR ENGINEERING
(2021)
Article
Thermodynamics
Yuxiu Li, Lin Diao, Ying Chen
Summary: This study analyzed the flow and heat transfer characteristics of supercritical CO2 heated in a helical coiled channel under one-side condition. The results showed that high heat transfer coefficient can be achieved by appropriate matching of heat flux and mass flux, with the CO2 fluid staying near pseudo-critical state. The semicircular heating mode enhanced the centrifugal effect and resulted in a crescent-shaped flow pattern with a large velocity gradient.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2022)
Proceedings Paper
Thermodynamics
Meiling Cai, Yuxiu Li, Ying Chen, Jinliang Xu, Longyan Zhang, Junpeng Lei
PROCEEDINGS OF THE ASME 6TH INTERNATIONAL CONFERENCE ON MICRO/NANOSCALE HEAT AND MASS TRANSFER, 2019
(2019)
Article
Physics, Multidisciplinary
Zheng Lin, Mo Song-Ping, Li Yu-Xiu, Chen Ying, Xu Jin-Liang
ACTA PHYSICA SINICA
(2019)
Article
Thermodynamics
Jinliang Xu, Yuxiu Li
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2007)
Article
Thermodynamics
Yuxiu Li, Jinliang Xu
NANOSCALE AND MICROSCALE THERMOPHYSICAL ENGINEERING
(2006)
Article
Thermodynamics
JL Xu, Y Li, TN Wong
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2005)
Article
Engineering, Electrical & Electronic
JL Xu, S Shen, YH Gan, YX Li, W Zhang, QC Su
JOURNAL OF MICROMECHANICS AND MICROENGINEERING
(2005)
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)
