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Numerical Simulation of Transient 3-D Turbulent Hested Jet into Crossflow in a Thick-Wall T-Junction Pipe

Journal of Thermal Science 2001年第1期10卷 46-51页

作者： Wu Hailing, Chen Tingkuan, Luo Yushan, Wang Haijun (state key laboratory of multiphase flow in power engineering,Xi’an Jiaotong University, Xi’an 710049, China) State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an China

The present work is to investigate the transient three-dimensional heated turbulent jet into crossflow in a thickwall T-junction pipe using CFD package. Two cases with the jet-to-crossflow velocity ratio of 0.05 and 0.5 are computed, with a finite-volume method utilizing κ-ε model. Comparison of the steady-state computations with measured data shows good qualitative agreement. Transient process of injection is simulated to examine the thermal shock on the T-junction component. Temporal temperature of the component is acquired by thermal coupling with the fluid. Via analysis of the flow and thermal characteristics, factors causing the thermal shock are studied. Optimal flow rates are discussed to reduce the thermal shock.

关键词： numerical simulation low jet-to-crossflow velocity ratio thick-wall T-junction pipe thermal shock

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Neural network-based interface reconstruction algorithm for two-phase fluid flow

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Fundamental Research 2025年

作者： Gong, Junhua Chen, Yujie Yu, Bo Sun, Dongliang Wang, Bohong Shi, Guoyun Chen, Bin State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 China School of Mechanical Engineering Beijing Institute of Petrochemical Technology Beijing 102617 China School of Petroleum Engineering Yangtze University Wuhan 430100 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 Zhoushan 316022 China Kunlun Digital Intelligence Technology Company Beijing 102266 China

In two-phase fluid flow, the vapor-liquid interface tends to behave as a curved shape under the influence of surface tension. Curve reconstruction favors improving the resolution of bubbles or droplets in numerical studies. Based on artificial neural network (ANN) and convolutional neural network (CNN), two curve reconstruction algorithms, namely CIR-ANN and CIR-CNN, are proposed in this study. Both algorithms can achieve high-precision prediction of the center and radius when reconstructing interfaces using a portion of a standard circle, especially for the CIR-CNN algorithm. A strict mass conservation strategy is also proposed to ensure the reliability of the neural network predictions. In comparison with interface reconstruction algorithms such as piecewise linear interface construction (PLIC) algorithm, efficient least squares volume-of-fluid interface reconstruction algorithm (ELVIRA), quadratic spline based interface (QUASI) reconstruction algorithm after the first interface correction, Circle-based Interface Reconstruction (CIR), and CIR-ANN algorithm, the proposed CIR-CNN demonstrates good advantages in static interface reconstruction, with average accuracy ratios of 48.40, 86.69, 26.34, 4.07 and 2.26. However, when capturing the bubble under a complex rotation and shear recovery flow field, the advantage of the proposed algorithms decreases due to the increased complexity of the fluid volume fraction distributions. Regarding the computational time cost of reconstructing random circular interfaces, the proposed algorithms achieve average reduction ratios of 4.16, 7.86, and 34.14, respectively, compared to the CIR, ELVIRA, and QUASI algorithms. © 2025

关键词： ANN CNN Curve reconstruction Neural network Two-phase flow

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High-Quality Critical Heat Flux in Horizontally Coiled Tubes

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Journal of Thermal Science 1995年第3期4卷 205-211页

作者： Weimin Ma Mingyuan Zhang Xuejun Chen (state key laboratory of multiphase flow in power engineering, Xi’an Jiaotong Universityt Xi’an 710049, China) State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an China

An investigation on the high-quality dryout in two electrically heated coiled tubes with horizontally helix axes is reported. The temperature profiles both along the tube and around the circumference are measured, and it is found that the temperature profiles around the circumference are not idelltical for the cross-sections at different parts of the coil. The 'local condition hypothesis' seems applicable under present conditions, and the critical heat flux qcr decreases with increasing critical quality xcr The CHF increases as mass velocity and ratio of tube diameter to coil diameter (d/D) increases, and it seems not to be effected by the system pressure. The CHF is larger with coils than that with straight tubes, and the difference increases with increasing mass velocity and d/D.

关键词： horizoatally coiled tube critical heat flux.

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Preparation of biochar adsorption material from walnut shell by supercritical CO_(2)pretreatment

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Biochar 2024年第1期6卷 168-185页

作者： Zitong Zhuang Yanbing Liu Wenwen Wei Jinwen Shi Hui Jin State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049People’s Republic of China.

In order to treat dyes in the wastewater of the printing industry and to reutilize walnut shell(WS)waste gener-ate economic benefits,supercritical carbon dioxide(SC-CO_(2))pretreatment technology was developed to prepare porous biochar as a precursor for adsorption *** experiments were conducted at the temperatures of 200,300,and 400℃with durations of 20,40,and 60 min,and a control group was set up using N_(2)***,KOH activation was employed to prepare biochar adsorption *** biochars were analyzed and characterized using TGA,BET,SEM,FT-IR,and XRD,and the liquid and gas phase products of the pretreatment process were analyzed semi-quantitatively and quantitatively using GC-MS and gas *** blue(MB)dye was selected as an indicator to measure the adsorption capacity of biochar,and adsorption kinetics were analyzed based on the *** results indicate that pretreatment with SC-CO_(2)effectively enhanced the performance and yield of the activated *** highest specific surface area increased by 18%,and the maximum adsorption of MB increased by 23%compared to the N_(2)control *** yield increased by 8-262%and the specific surface area increased by 50-192%compared to the direct activation of walnut shell(WS).During the pretreatment processes for the preparation of biochar adsorption material with the best specific surface area,phenol-enriched bio-oil was produced as a by-product which has economic value.

关键词： Supercritical carbon dioxide Walnut shell Biochar Methylene blue adsorption

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Numerical Investigation of Developing Turbulent flow in a Helical Square Ductwith Large Curvature

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Journal of Thermal Science 2001年第1期10卷 1-6页

作者： Gao Hui,Guo Liejin (state key laboratory of multiphase flow in power engineering, Xi’an Jiaotong University, Xi’an 710049, China ) State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an China

A fully elliptic numerical study has been carried out to investigate the three-dimensional turbulent developing flow in a helical square duct with large curvature. A two-layer zonal model is proposed and used, in which the whole region is divided into a viscosity-affected near wall layer and a fully turbulent region. A DSM closure is applied in the former, and a one-equation model is solved in the latter. The results presented in this paper cover a Reynolds number range of (l- 10) x 104. The development of flow is found to be dominated by radial pressure gradient and Dean-type secondary motion. The distribution of Reynolds stresses in fully developed flow exhibit a complex pattern of turbulence anisotropy The development of peripherally averaged friction factor and the distribution of local friction factor in fully developed flow are given and discussed.

关键词： curved pipe developing flow turbulence model numerical simulation.

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Recent advances in nonmetallic atom-doped metal nanocrystals:Synthesis and catalytic applications

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Chinese Chemical Letters 2021年第9期32卷 2679-2692页

作者： Ruiyun Guo Ke Zhang Shangdong Ji Yangzi Zheng Mingshang Jin Frontier Institute of Science and Technology and State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an 710049China

Metal nanocrystals have been recognized as the main catalytic materials in many fields,but insufficient activity and stability,as well as high prices,have limited their large-scale potential *** one of the extremely promising alternatives toward metal in boosting their catalytic performance,nonmetallic atoms-doped metal nanocrystals have recently received extensive attention because of their high efficiency,chemical and structural durability,abundant reserve,and low *** this review,we highlight the most recent progress in this field and provide insights into their catalytic *** metalnonmetal nanocrystals prepared by doping metal nanocrystals with nonmetallic atoms are introduced and classified based on the types of nonmetallic atoms,including metal hydrides,borides,carbides,nitrides,oxides,phosphides,and ***,their applications in catalysis,especially in electrocatalysis and organic catalysis,have been summarized and ***,the conclusions and perspectives are given for the catalysis-driven rational design of metal-nonmetal nanocrystals in this minireview.

关键词： Nonmetallic atom-doping Metal-nonmetal nanocrystals Organic catalysis Electrocatalysis Catalyst design

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Improving sampling depth of laser speckle imaging by topical optical clearing:A theoretical and in vivo study

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Journal of Innovative Optical Health Sciences 2020年第2期13卷 33-43页

作者： D.Li Y.Zhang B.Chen State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an Shaanxi 710049P.R.China

The effect of optical cleaning method combined with laser speckle imaging(LSI)was discussed to improve the detection depth of LSI due to high scattering characteristics of skin,which limit its clinical application.A double-layer skin tissue model embedded with a single blood vessel was established,and the Monte Carlo method was used to simulate photon propagation under the action of light-permeating agent.808 nm semiconductor and 632.8 nm He–Ne lasers were selected to study the e®ect of optical clearing agents(OCAs)on photon deposition in *** show that the photon energy deposition density in the epidermis increases with the amount of tissue°uid replaced by *** with glucose solution,polyethylene glycol 400(PEG 400)and glycerol can considerably increase the average penetration depth of photons in the skin tissue,thereby raising the sampling depth of the *** the action of glycerol,PEG 400,and glucose,the average photon penetration depth is increased by 51.78%,51.06%,and 21.51%for 808nm,68.93%,67.94%,and 26.67%for 632.8 nm lasers,*** vivo experiment by dorsal skin chamber proves that glycerol can cause a substantial decrease in blood°ow rate,whereas PEG 400 can signicantly improve the capability of light penetration without a®ecting blood velocity,which exhibits considerable potential in the monitoring of blood°ow in skin tissues.

关键词： Laser speckle image topical optical clearing imaging depth Monte-Carlo simulation dorsal skin experiment

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Dynamic simulation of a space gas-cooled reactor power system with a closed Brayton cycle

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Frontiers in Energy 2021年第4期15卷 916-929页

作者： Chenglong WANG Ran ZHANG Kailun GUO Dalin ZHANG Wenxi TIAN Suizheng QIU Guanghui SU Department of Nuclear Science and Technology State Key Laboratory of Multiphase Flow in Power EngineeringShaanxi Key Laboratory of Advanced Nuclear Energy and TechnologyXi’an Jiaotong UniversityXi’an 710049China

Space nuclear reactor power(SNRP)using a gas-cooled reactor(GCR)and a closed Brayton cycle(CBC)is the ideal choice for future high-power space *** investigate the safety characteristics and develop the control strategies for gas-cooled SNRP,transient models for GCR,energy conversion unit,pipes,heat exchangers,pump and heat pipe radiator are established and a system analysis code is developed in this ***,analyses of several operation conditions are performed using this *** full-power steady-state operation,the core hot spot of 1293 K occurs near the upper part of the *** 0.4$reactivity is introduced into the core,the maximum temperature that the fuel can reach is 2059 K,which is 914 K lower than the fuel melting *** system finally has the ability to achieve a new steady-state with a higher reactor *** the GCR is shut down in an emergency,the residual heat of the reactor can be removed through the conduction of the core and radiation heat *** results indicate that the designed GCR is inherently safe owing to its negative reactivity feedback and passive decay heat *** paper may provide valuable references for safety design and analysis of the gas-cooled SNRP coupled with CBC.

关键词： gas-cooled space nuclear reactor power closed Brayton cycle system startup and shutdown positive reactivity insertion accident

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Experimental and modeling investigation of zero net liquid flow in hilly terrain pipeline

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Petroleum Science 2025年

作者： Bo Huang Qiang Xu Ying-Jie Chang Ye-Qi Cao Hai-Yang Yu Yu-Wen Li Lie-Jin Guo State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 Shaanxi China College of Petroleum Engineering Xi’an Shiyou University 710065 Shaanxi China

Hilly terrain pipeline is a common form of pipeline in oil and gas storage and transportation industry. Due to the hilly terrain influence, the liquid at the elbow of the gathering pipeline is easy to flow back and accumulate to form slug flow, so it is necessary to remove the accumulated liquid by gas purging. In this paper, experiment is carried out in hilly terrain pipelines. Three flow patterns of stratified flow, slug flow and stratified entrained flow are observed. The process of gas purging accumulated liquid is divided into four stages, namely liquid accumulation, liquid rising; continuous outflow and tail outflow. At the same time, the flow pattern maps of each stage are drawn. The pressure drop signal is analyzed in time domain and frequency domain, and the contour map of pressure drop distribution is drawn. It is found that the ratio of range to average value can well distinguish the occurrence range of each flow pattern. Based on visualization, the transition process of slug flow to stratified flow and stratified entrained flow is studied, and the transition boundary prediction model is established. An image processing method is proposed to convert the image signal into a similarity curve, and PSD analysis is performed to calculate the slug frequency. The normal distribution is used to fit the slug frequency, and the predicted correlation is in good agreement with the experimental data.

关键词： Hilly terrain pipeline Zero net liquid flow Slug flow flow pattern transition Quantitative image processing

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Toward the influence of fluid convection on filtered drag force in fluidized gas-particle flows

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Powder Technology 2025年 460卷

作者： Jiang, Ju Yuan, Shouzheng Chen, Xiao Yang, Bolun Zhou, Qiang School of Chemical Engineering and Technology Xi'an Jiaotong University Xi'an710049 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

Mesoscale drag modeling for gas-solid flows is typically based on fully-periodic systems where fluid convection is insignificant. This study examines a series of 2D sudden-expanded fluidized beds (SEFBs) to investigate the effects of fluid convection on the filtered drag force. A priori analysis indicates that the volumetric force induced by convection has a notable impact on the filtered drag force, and correlations of drag force using traditional markers (such as solid volume fraction, slip velocity, and filter size) fail to provide accurate predictions. In contrast, the gas-phase pressure gradient shows a good correlation with drag force when strong convection is present. Posterior tests in the SEFBs with several existing drag models reveal that the predictive capacity of drag models constructed with traditional markers declines under conditions with strong convection, whereas the drag model incorporating the gas-phase pressure gradient still performs well. © 2025 Elsevier B.V.

关键词： Drag coefficient

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