FABRICATING WELL-DISPERSED NANOSIZED GOLD CATALYST ON TITANATE NANOWIRES SURFACE FOR 4-NITROPHENOL REDUCTION

GUANGLIANG CHEN,FEI XUE,ZHILI CHEN,XIAOLEI SI,JUN HUANG,XU ZHENG,SYLVAIN MASSEY 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2014 NANO Vol.9 No.3

In this paper, homogenous gold nanoparticles (AuNPs) with a high density and a narrow sizedistribution were successfully fabricated on titanate nanowires (TNWs) sca®olds in the absenceof organic capping agents. An ameliorated low-temperature hydrothermal method was used toprepare the TNWs sca®olds like bird's nest on the Ti substrate, and the nanowires diameter wasabout 30 – 80nm. Then, AuNPs were synthesized on the TNWs sca®olds with a deposition –precipitation urea (DPU) method. The TEM and XRD measurements indicated that well-crys-tallized face-centered cubic (fcc) AuNPs were homogeneously dispersed on TNWs, and AuNPswith average sizes of 2.7 nm and 4 nm were obtained, respectively for the theoretical gold loading5 wt.% and 8 wt.%. Inspiringly, the 8%-AuNPs/TNWs catalyst could reduce 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) within 210 s, and exhibited better catalytic reduction performancethan that of 5%-AuNPs/TNWs.

Design and analysis of RIF scheme to improve the CFD efficiency of rod-type PWR core

Chen, Guangliang,Qian, Hao,Li, Lei,Yu, Yang,Zhang, Zhijian,Tian, Zhaofei,Li, Xiaochang Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.10

This research serves to advance the development of engineering computational fluid dynamics (CFD) computing efficiency for the analysis of pressurized water reactor (PWR) core using rod-type fuel assemblies with mixing vanes (one kind of typical PWR core). In this research, a CFD scheme based on the reconstruction of the initial fine flow field (RIF CFD scheme) is proposed and analyzed. The RIF scheme is based on the quantitative regulation of flow velocities in the rod-type PWR core and the principle that the CFD computing efficiency can be improved greatly by a perfect initialization. In this paper, it is discovered that the RIF scheme can significantly improve the computing efficiency of the CFD computation for the rod-type PWR core. Furthermore, the RIF scheme also can reduce the computing resources needed for effective data storage of the large fluid domain in a rod-type PWR core. Moreover, a flow-ranking RIF CFD scheme is also designed based on the ranking of the flow rate, which enhances the utilization of the flow field with a closed flow rate to reconstruct the fine flow field. The flow-ranking RIF CFD scheme also proved to be very effective in improving the CFD efficiency for the rod-type PWR core.

Analysis of the performances of the CFD schemes used for coupling computation

Chen, Guangliang,Jiang, Hongwei,Kang, Huilun,Ma, Rui,Li, Lei,Yu, Yang,Li, Xiaochang Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.7

In this paper, the coupling of fine-mesh computational fluid dynamics (CFD) thermal-hydraulics (TH) code and neutronics code is achieved using the Ansys Fluent User Defined Function (UDF) for code development, including parallel meshing mapping, data computation, and data transfer. Also, some CFD schemes are designed for mesh mapping and data transfer to guarantee physical conservation in the coupling computation. Because there is no rigorous research that gives robust guidance on the various CFD schemes that must be obtained before the fine-mesh coupling computation, this work presents a quantitative analysis of the CFD meshing and mapping schemes to improve the accuracy of the value and location of key physical prediction. Furthermore, the effect of the sub-pin scale coupling computation is also studied. It is observed that even the pin-resolved coupling computation can also create a large deviation in the maximum value and spatial locations, which also proves the significance of the research on mesh mapping and data transfer for CFD code in a coupling computation.

Preliminary study on the thermal-mechanical performance of the U₃Si₂/Al dispersion fuel plate under normal conditions

Yang, Guangliang,Liao, Hailong,Ding, Tao,Chen, Hongli Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.11

The harsh conditions in the reactor affect the thermal and mechanical performance of the fuel plate heavily. Some in-pile behaviors, like fission-induced swelling, can cause a large deformation of fuel plate at very high burnup, which may even disturb the flow of coolant. In this research, the emphasis is put on the thermal expansion, fission-induced swelling, interaction layer (IL) growth, creep of the fuel meat, and plasticity of the cladding for the U₃Si₂/Al dispersion fuel plate. A detailed model of the fuel meat swelling is developed. Taking these in-pile behaviors into consideration, the three-dimensional large deformation incremental constitutive relations and stress update algorithms have been developed to study its thermal-mechanical performance under normal conditions using Abaqus. Results have shown that IL can effectively decrease the thermal conductivity of fuel meat. The high Mises stress region mainly locates at the interface between fuel meat and cladding, especially around the side edge of the interface. With irradiation time increasing, the stress in the fuel plate gets larger resulting from the growth of fuel meat swelling but then decreases under the effect of creep deformation. For the cladding, plasticity deformation does not occur within the irradiation time.

Direct Synthesis of H2O2 over Ti-Containing Molecular Sieves Supported Gold Catalysts: A Comparative Study for In-situ-H2O2-ODS of Fuel

Han Zhang,Guangliang Liu,Haiyan Song,Chunxia Chen,Fuqin Han,Ping Chen,Zhixi Zhao,Shaozheng Hu 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.10

Direct synthesis of H2O2 and in situ oxidative desulfurization of model fuel over Au/Ti-HMS and Au/TS-1 catalysts has been comparatively investigated in water or methanol. Maximum amount (82%) of active Au0 species for H2O2 synthesis was obtained. Au/Ti-HMS and Au/TS-1 exhibited the contrary performances in H2O2 synthesis as CH3OH/H2O ratio of solvent changed. H2O2 decomposition and hydrogenation in water was inhibited by the introduction of methanol. Effect of O2/H2 ratio on H2O2 concentration, H2 conversion and H2O2 selectivity revealed a relationship between H2O2 generation and H2 consumption. The highest dibenzothiophene removal rate (83.2%) was obtained over Au/Ti-HMS in methanol at 1.5 of O2/H2 ratio and 60 oC. But removal of thiophene over Au/TS-1 should be performed in water without heating to obtain a high removal rate (61.3%). Meanwhile, H2 conversion and oxidative desulfurization selectivity of H2 were presented.

HIGHLY CATALYTIC Ag/Co3O4 NANOCATALYSTS FABRICATED FOR RhB DYE DEGRADATION THROUGH A SIMPLE SILVER-MIRROR REACTION UNDER VISIBLE LIGHT

XIAOLEI SI,GUANGLIANG CHEN,Zhili Chen,JUN HUANG 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2014 NANO Vol.9 No.8

In this paper, a highly catalytic and nanosized Ag/Co3O4 composite for rhodamine B (RhB) degradation was fabricated by using the co-precipitation method at room temperature. The Ag/Co3O4 structure and catalytic properties were characterized through scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET) gassorption measurements, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV-Vis spectroscopy. The results showed that the Co3O4 nanosheets prepared by hydrothermal synthesis mainly exposed (2 2 0) and (1 1 1) facets, which played an important role in determining its catalytic oxidation performance. The Co3O4 nanosheets doped with Ag nanoparticles by a simple silver-mirror reaction exhibited a stable and well-dispersed property in dye solution. Compared to the Ag and Co3O4 nanostructure, the Ag nanoparticles with bigger diameter (10 nm) on Co3O4 surface also readily produced surface-active oxygen species and exhibited a higher catalytic activity for the degradation of RhB solution (5 mg·L-1) under the visible light. The kinetic constant K of Ag/Co3O4 catalyst for RhB degradation reaction was evaluated to0.02724 min-1, which is relatively higher than those reported in the literatures.

Development of supporting platform for the fine flow characteristics of reactor core

Qian Hao,Chen Guangliang,Li Lei,Zhang Lixuan,Yin Xinli,Zhang Hanqi,Su Shaomin 한국원자력학회 2024 Nuclear Engineering and Technology Vol.56 No.5

This study presents the Supporting platform for reactor fine flow characteristics calculation and analysis (Cilian platform), a user-friendly tool that supports the analysis and optimization of pressurized water reactor (PWR) cores with mixing vanes using computational fluid dynamics (CFD) computing. The Cilian platform allows for easy creation and optimization of PWR’s main CFD calculation schemes and autonomously manages CFD calculation and analysis of PWR cores, reducing the need for human and computational resources. The platform’s key features enable efficient simulation, rapid solution design, automatic calculation of core scheme options, and streamlined data extraction and processing techniques. The Cilian platform’s capability to call external CFD software reduces the development time and cost while improving the accuracy and reliability of the results. In conclusion, the Cilian platform exemplifies an innovative solution for efficient computational fluid dynamics analysis of pressurized water reactor (PWR) cores. It holds great promise for driving advancements in nuclear power technology, enhancing the safety, efficiency, and cost-effectiveness of nuclear reactors. The platform adopts a modular design methodology, enabling the swift and accurate computation and analysis of diverse flow regions within core components. This design approach facilitates the seamless integration of multiple computational modules across various reactor types, providing a high degree of flexibility and reusability

Direct Synthesis of H₂O₂ over Ti-Containing Molecular Sieves Supported Gold Catalysts: A Comparative Study for In-situ-H₂O₂-ODS of Fuel

Zhang, Han,Liu, Guangliang,Song, Haiyan,Chen, Chunxia,Han, Fuqin,Chen, Ping,Zhao, Zhixi,Hu, Shaozheng Korean Chemical Society 2013 Bulletin of the Korean Chemical Society Vol.34 No.10

Direct synthesis of $H_2O_2$ and in situ oxidative desulfurization of model fuel over Au/Ti-HMS and Au/TS-1 catalysts has been comparatively investigated in water or methanol. Maximum amount (82%) of active $Au^0$ species for $H_2O_2$ synthesis was obtained. Au/Ti-HMS and Au/TS-1 exhibited the contrary performances in $H_2O_2$ synthesis as $CH_3OH/H_2O$ ratio of solvent changed. $H_2O_2$ decomposition and hydrogenation in water was inhibited by the introduction of methanol. Effect of $O_2/H_2$ ratio on $H_2O_2$ concentration, $H_2$ conversion and $H_2O_2$ selectivity revealed a relationship between $H_2O_2$ generation and $H_2$ consumption. The highest dibenzothiophene removal rate (83.2%) was obtained over Au/Ti-HMS in methanol at 1.5 of $O_2/H_2$ ratio and $60^{\circ}C$. But removal of thiophene over Au/TS-1 should be performed in water without heating to obtain a high removal rate (61.3%). Meanwhile, $H_2$ conversion and oxidative desulfurization selectivity of $H_2$ were presented.

Application of POD reduced-order algorithm on data-driven modeling of rod bundle

Huilun Kang,Zhaofei Tian,Guangliang Chen,Lei Li,Tianyu Wang 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.1

As a valid numerical method to obtain a high-resolution result of a flow field, computational fluid dynamics (CFD) have been widely used to study coolant flow and heat transfer characteristics in fuel rod bundles. However, the time-consuming, iterative calculation of Navier-Stokes equations makes CFD unsuitable for the scenarios that require efficient simulation such as sensitivity analysis and uncertainty quantification. To solve this problem, a reduced-order model (ROM) based on proper orthogonal decomposition (POD) and machine learning (ML) is proposed to simulate the flow field efficiently. Firstly, a validated CFD model to output the flow field data set of the rod bundle is established. Secondly, based on the POD method, the modes and corresponding coefficients of the flow field were extracted. Then, an deep feed-forward neural network, due to its efficiency in approximating arbitrary functions and its ability to handle high-dimensional and strong nonlinear problems, is selected to build a model that maps the non-linear relationship between the mode coefficients and the boundary conditions. A trained surrogate model for modes coefficients prediction is obtained after a certain number of training iterations. Finally, the flow field is reconstructed by combining the product of the POD basis and coefficients. Based on the test dataset, an evaluation of the ROM is carried out. The evaluation results show that the proposed POD-ROM accurately describe the flow status of the fluid field in rod bundles with high resolution in only a few milliseconds.

Investigation on the nonintrusive multi-fidelity reduced-order modeling for PWR rod bundles

Huilun Kang,Zhaofei Tian,Guangliang Chen,Lei Li,Tianhui Chu 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.5

Performing high-fidelity computational fluid dynamics (HF-CFD) to predict the flow and heat transferstate of the coolant in the reactor core is expensive, especially in scenarios that require extensiveparameter search, such as uncertainty analysis and design optimization. This work investigated theperformance of utilizing a multi-fidelity reduced-order model (MF-ROM) in PWR rod bundles simulation. Firstly, basis vectors and basis vector coefficients of high-fidelity and low-fidelity CFD results areextracted separately by the proper orthogonal decomposition (POD) approach. Secondly, a surrogatemodel is trained to map the relationship between the extracted coefficients from different fidelity results. In the prediction stage, the coefficients of the low-fidelity data under the new operating conditions areextracted by using the obtained POD basis vectors. Then, the trained surrogate model uses the lowfidelity coefficients to regress the high-fidelity coefficients. The predicted high-fidelity data is reconstructed from the product of extracted basis vectors and the regression coefficients. The effectiveness ofthe MF-ROM is evaluated on a flow and heat transfer problem in PWR fuel rod bundles. Two data-drivenalgorithms, the Kriging and artificial neural network (ANN), are trained as surrogate models for the MFROM to reconstruct the complex flow and heat transfer field downstream of the mixing vanes. The results show good agreements between the data reconstructed with the trained MF-ROM and the highfidelity CFD simulation result, while the former only requires to taken the computational burden oflow-fidelity simulation. The results also show that the performance of the ANN model is slightly betterthan the Kriging model when using a high number of POD basis vectors for regression. Moreover, theresult presented in this paper demonstrates the suitability of the proposed MF-ROM for high-fidelityfixed value initialization to accelerate complex simulation