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Verification and validation plus uncertainty quantification of heat transfer simulation for liquid metal in wire-wrapped rod assembly

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International Communications in Heat and Mass Transfer 2025年 165卷

作者： Zhenglong Liu Peiling Zhong Hanrui Qiu Mingjun Wang Wenxi Tian Guanghui Su State Key Laboratory of Multiphase Flow in Power Engineering Department of Nuclear Science and Technology Xi'an Jiaotong University Xi'an 710049 China

A complete CFD best practice process is proposed, including Phenomena Identification and Ranking Table (PIRT), Verification and Validation (V&V), and Uncertainty Quantification (UQ). The heat transfer of liquid metal within a rod assembly under both normal and blocked conditions is used as an example to demonstrate the full CFD process. key flow and heat transfer phenomena are identified, and model sensitivity analyses are performed based on these phenomena. Turbulent Prandtl models, porous blockage models and different meshing strategies sensitivity analysis are conducted. Uncertainty quantification is performed. The discretization uncertainty is calculated using the Grid Convergence Index (GCI). The convergence orders are greater than unity for all cases except the fluid temperature in the blocked condition using meshing strategy 2. The input parameter uncertainty is estimated using finite difference. The model uncertainty is derived. Under normal condition, the model uncertainty of the wall and fluid temperatures are 2.88 K and 3.37 K, respectively. Under blocked condition, the model uncertainty of wall temperature is slightly higher than fluid temperature. The wall temperature uncertainty for strategies 1 and 2 are 8.46 K and 9.03 K, while the fluid uncertainty of strategy 1 and 2 are 3.57 K and 3.06 K, respectively.

关键词： Liquid metals

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Simulation of flow across complicated domain between tube bundles by the discrete vortex method

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自然科学进展(英文版) 2003年第3期13卷 213-218页

作者： CHEN Bin Guo Liejin Yang Xiaogang State Key Laboratory of Multiphase Flow in Power Engineering Xi'an J iaotong University Xi'an 710049 China

On the basis of the analysis of numerical simulation methods for the complicated domain between tube bundles, an improved Lagragian discrete vortex method (DVM) and corresponding algorithm are put forward to solve the practical difficulties of flow across tube bundles. With this method the amount of vortices can be reduced considerably, which makes quick calculation possible. Applied to the practical configuration of horizontal tube bundles, the DVM simulation is carried out and compared with the experimental results. Both the transient flow field and the profile of mean velocity and fluctuations are in good agreement with experimental results, which indicate that the DVM is suitable for the simulation of single-phase flow across tube bundles.

关键词： tube bundles discrete vortex method numerical simulation

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Rapid modeling of transient processes in hydrogen-blended natural gas pipelines featuring injection and withdrawal points

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International Journal of Hydrogen Energy 2025年

作者： Gong, Junhua Zhou, Chaoqun Wang, Yanxin Deng, Yajun Chen, Yujie Wang, Peng Yu, Bo Chen, Bin Yu, Zhipeng Wang, Bohong School of Mechanical Engineering Beijing Institute of Petrochemical Technology Beijing102617 China Changqing Oil and Gas Transportation Branch of Northwest Company of PipeChina Xingqing District Ningxia Yinchuan City750004 China PipeChina Engineering Technology Innovation Co.Ltd Tianjin300450 China School of Petroleum Engineering Yangtze University Wuhan430100 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China National & Local Joint Engineering Research Center of Harbor Oil & Gas Storage and Transportation Technology/Zhejiang Key Laboratory of Pollution Control for Port-Petrochemical Industry Zhejiang Ocean University Zhoushan316022 China

Blending hydrogen into natural gas pipelines enables the large-scale delivery and application of hydrogen, contributing to carbon emission reduction and promoting the transition to cleaner energy sources. Accurate and efficient predictions of transient processes in such pipelines are critical for effective management and operation. This study proposes a Fourier Neural Operator (FNO)-based model for the rapid prediction of transient processes in hydrogen-blended pipelines with injection and withdrawal points. The model is trained using numerical simulation data of pressure and flow dynamics, with initial conditions, boundary conditions, and the hydrogen blending ratio as inputs to predict hydraulic parameters along the pipeline over time. By optimizing data preprocessing and neural network hyperparameters, the model achieves high accuracy and efficiency in predicting hydraulic states. The FNO model achieves average Root Mean Squared Errors (RMSEs) of 1.06 × 10−3, 1.64 × 10−3, and 7.40 × 10−4 for pressure, flow rate, and density, respectively, with the Coefficient of Determination (R2) exceeding 0.99 for all three variables. Furthermore, the model demonstrates strong generalization capabilities, accurately predicting hydraulic states for pipeline topologies and scenarios beyond the training data. In these cases, the RMSE remains in the order of 10−3 or smaller. For a 100 km pipeline, the computational efficiency of the FNO model is at least 969 times higher than that of traditional numerical methods, with the maximum efficiency improvement reaching 5168 times as the number of pipeline cases simultaneously predicted increases. These results highlight the potential of the FNO model for real-time applications in hydrogen-blended natural gas pipeline management. © 2025 Hydrogen Energy Publications LLC

关键词： Mean square error

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Morphology Structure Evolution and Combustion Reactivity of Bituminous Char at Around Ash Melting Temperature

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Journal of Thermal Science 2022年第6期31卷 2189-2202页

作者： ZHANG Yandi YANG Huan WANG Bo HMShahzaib KHAN DUAN Xiaoli LIU Yinhe State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi'an Jiaotong UniversityXi'an 710049China

In slag tapping furnaces, char particles undergo a series of complex structural evolution before and after being captured by the liquid slag layer. The evolution results affect the carbon conversion rate and are affected by temperature fluctuations, especially in the ash melting temperature zone. Experimental study on structure evolution of bituminous char prepared at around ash melting temperature was carried out on a fixed bed. The morphology, specific surface area and mineral chemical composition were measured at different temperatures. Experimental results show that the number density and the size of ash droplets exuded on the char surface increased significantly with the increasing temperature. The ash specific surface area from gasification was slightly greater than that from combustion. The residual content of chloride in the char become 1% and the contents of Fe, K, Mg and Na decrease significantly during the pyrolysis process across the ash melting temperature zone. The diffraction intensity of oldhamite increase which indicates the reaction of carbon substrate with minerals during the evolution;the diffraction intensity of quartz dramatically decreases for the reason of anorthite generation. The ignition and burnout temperatures of char were found to increase and the combustion stability decreased with the increasing pyrolysis temperature.

关键词： coal char structure evolution carbothermal reaction combustion

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Wall-to-bed heat transfer in supercritical water fluidized bed using CFD-DEM

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Particuology 2021年第3期19卷 113-123页

作者： Tianning Zhang Youjun Lu State Key Laboratory of Multiphase Flow in Power Engineering(SKLMFPE) Xi’an Jiaotong UniversityXi’anShaanxi 710049PR China

Supercritical water fluidized bed(SCWFB)reactors are designed to gasify biomass or coal with high *** this paper,the wall-to-bed heat transfer characteristics in SCWFB are studied using the computational fluid dynamics and discrete element method(CFD-DEM)coupled with a constant heat flux *** different methods are considered to deal with the multiphase heat flux boundary in CFD-DEM because there is currently no single widely accepted ***’s method predicts a more accurate wall-to-bed heat transfer coefficient in SCWFB than Lattanzi’s method according to comparisons of the simulation results with an empirical *** influences of temperature,pressure,velocity,and the solid phase properties,such as the particle diameter,particle heat capacity,particle thermal conductivity,and particle density,on the SCWFB wall-to-bed heat transfer characteristics are studied based on Zhang’s *** simulation results help reveal the SCWFB heat transfer characteristics.

关键词： Supercritical water Fluidized bed Heat transfer DEM-CFD Constant heat flux

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Operational efficiency improvement in a water supply network: Machine learning-enhanced leakage identification and water resource conservation

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Journal of Water Process engineering 2025年 75卷

作者： Liu, Hongbo Zhang, Junbo An, Wenhui Chen, Yang Yuan, Xiang Zhang, Guosheng Lichtfouse, Eric Ma, Jiale Huang, Jin Tu, Yiqian School of Environment and Architecture University of Shanghai for Science and Technology 516 Jungong Road Shanghai 200093 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Shaanxi Xi'an 710049 China Shanghai Urban Construction Design and Research Institute (Group) Co. Ltd. Shanghai 200125 China

Pipeline ruptures in water supply networks can induce significant water loss and may pose risks of water quality deterioration, including potential contamination by pathogens and pollutants. This issue can be addressed by predicting the location of leakage points in the pipeline network and controlling the leakage. Here we designed a hydraulic model for leakage localization using a genetic algorithm-backpropagation neural network, to predict the leakage points in the water supply system of an exposition area consuming 117,211 m³ of water per day in Eastern China. Then, using the model results, pressure-regulating valves were installed in areas with lower network safety. Results show that the error in predicting the leakage points localization ranged from 14.48 m to 121.69 m. The installation of pressure-regulating valves, reduced the average water pressure from 33.54 m to 32.64 m (2.7 %) and, in turn, decreased the simulated background leakage by 9684 m³ of water per day. Compared to traditional acoustic-based methods, the proposed machine learning approach enables more accurate leak localization by leveraging pressure variation features. © 2025 Elsevier Ltd

关键词： Pipeline leakage Point leakage model Pressure monitoring Pressure regulating valve Supply water

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Extension of the pressure correction method to zero-Mach number compressible flows

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Science China(Technological Sciences) 2009年第6期52卷 1583-1595页

作者： HE YaLing HUANG Jing TAO YuBing TAO WenQuan State Key Laboratory of Multiphase Flow in Power Engineering School of Energy&Power EngineeringXi’an Jiaotong UniversityXi’an 710049China

In the present paper,the classical pressure correction method was extended into low Mach number compressible flow regime by integrating equation of state into SIMPLE *** self-developed code based on this algorithm was applied to predicting the lid-driven cavity flow and shock tube prob-lems,and the results showed good agreement with benchmark solutions and the Mach number can reach the magnitude of as low as *** attenuation of sound waves in viscous medium was then *** results agree well with the analytical solutions given by theoretical *** demonstrated that the present method could also be implemented in acoustics field simulation,which is crucial for thermoacoustic simulation.

关键词： thermoacoustic engine pressure correction method low Mach number compressible flow

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Study on Liutex-driven reward for intelligent flow control by dynamic feature-based deep reinforcement learning

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AIP Advances 2025年第5期15卷

作者： Wang, Qi Dong, Xiangrui You, Sunyu Cai, Xiaoshu School of Energy and Power Engineering University of Shanghai for Science and Technology Shanghai200093 China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer for Power Engineering Shanghai200093 China

The issue of flow separation over an airfoil under weak turbulent conditions is addressed and resolved through the deep reinforcement learning (DRL) strategy. To suppress the generation of separation flow and the instability of the vortex shedding alley over an airfoil, a novel reward function named RLiutex, considering the suppression of the rigid rotation intensity and core size of the vortex, is first proposed in this paper. The great potential of this Liutex-driven reward for effective large eddy elimination and aerodynamic optimization is verified in this work. Furthermore, a dynamic feature-based DRL (DF-DRL) framework is redeveloped to markedly enhance the learning efficiency and convergence speed. The combination of the Liutex-driven reward function with the DF-DRL framework results in an exceptional aerodynamic performance, with minimal fluctuations in both drag and lift coefficients, highlighting the potential of this approach for advanced flow control strategies. © 2025 Author(s).

关键词： Deep reinforcement learning

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Numerical simulation of flow characteristics for a labyrinth passage in a pressure valve

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Journal of Hydrodynamics 2016年第4期28卷 629-636页

作者：王海民赵越汪建兴孔祥帅刘欢李科良王喜芳 School of Energy and Power Engineering University of Shanghai for Science and Technology Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering University of Shanghai for Science and Technology

A tortuous labyrinth passage consists of a series of right angle turns in a disk of high pressure control *** this paper,numerical simulations are made for the velocity and pressure distributions in this *** is shown that the “series passage” can induce a pressure dropping more *** main function of the “series passage” is to induce a pressure dropping while the “parallel passage” is mainly to regulate the *** a cross sectional area process,a series of reduction and expansion,the pressure will also see dropping and partial recovery,which is called the multistage pressure *** this way,the velocity can be controlled in a reasonable level anywhere in this tortuous labyrinth *** the fluid pressure dropping in a downwards serrated way,the pressure is higher than the local saturate vapor pressure,therefore,no cavitation is induced by the phase transition.

关键词： passage valve dropping multistage turns sectional anywhere regulate vortex inlet

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Ferrites boosting photocatalytic hydrogen evolution over graphitic carbon nitride: a case study of(Co, Ni)Fe_2O_4 modification

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Science Bulletin 2016年第4期61卷 292-301页

作者： Jie Chen Daming Zhao Zhidan Diao Miao Wang Shaohua Shen International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University

The charge cartier separation and surface catalytic redox reactions are of primary importance as elementary steps in photocatalytic hydrogen evolution. In this study, both of these two processes in photocatalytic hydrogen evolution over graphitic carbon nitride （g-C3N4） were greatly promoted with the earth-abundant ferrites （Co, Ni）Fe2O4 modification. CoFe2O4 was further demonstrated to be a better modifier for g-C3N4 as compared to NiFe2O4, due to the more efficient charge carrier transfer as well as superior surface oxidative catalytic activity. When together loading CoFe2O4 and reductive hydrogen production electrocatalyst Pt onto g-C3N4, the obtained Pt/g-C3N4/CoFe2O4 photocatalyst achieved visible-light （2 〉 420 nm） hydrogen production rate 3.5 times as high as Pt/g-C3N4, with the apparent quantum yield reaching 3.35 % at 420 nm.

关键词： Graphitic carbon nitride FerritesPhotocatalytic water splitting Solar hydrogenconversion

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