Monte Carlo shielding evaluation of a CSNS Multi-Physics instrument

Tairan Liang,Fei Shen,Wen Yin,Juping Xu,Quanzhi Yu,Tianjiao Liang 한국원자력학회 2019 Nuclear Engineering and Technology Vol.51 No.8

The Multi-Physics (MP) instrument is one of 20 neutron spectrometers planned in the China Spallation Neutron Source (CSNS). This paper presents a shielding calculation for the MP instrument using Monte Carlo codes MCNPX and FLUKA. First, the neutrons that escape from the CSNS decoupled water moderator and are delivered to the beam line of the MP instrument are calculated to use as the source term of the shielding calculation. Then, to validate the calculation method based on multiple variance reduction techniques, a cross check between MCNPX and FLUKA codes is performed by comparing the calculation results of the dose rate distribution on a simplified beam line model. Finally, a complete geometry model of the MP instrument is set up, and the primary parameters for the shielding design are obtained according to the calculated dose rate map considering different worst-case scenarios.

Effects of fluid thermophysical properties on cavitating flows

Tairan Chen,Biao Huang,Guoyu Wang,Kun Wang 대한기계학회 2015 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.29 No.10

We studied the thermo-fluid cavitating flows and evaluated the effects of physical properties on cavitation behaviors. The thermo-fluid(including liquid nitrogen, liquid hydrogen and hot water) cavitating flows around a 2D hydrofoil were numerically investigated. TheFavre-averaged Navier-Stokes equations with the enthalpy-based energy equation, transport equation-based cavitation model, and the k-ω SST turbulence model were applied. The thermodynamic parameter Σ, defined as ( 2 2 ) / ( 2 ) v l v l r L r C T e ¥ å = was used to assess thethermodynamic effects on cavitating flows. The results manifest that the thermal energy solution case yields a substantially shorter andmushier cavity attached on the hydrofoil due to the thermodynamic effects, which shows better agreement with the experimental data. The temperature drop inside the cavity decreases the local saturated vapor pressure and hence increases the local cavitation number; itcould delay or suppress the occurrence and development of the cavitation behavior. The thermodynamic effects can be evaluated bythermophysical properties under the same free-stream conditions; the thermodynamic parameter Σ is shown to be critical in accuratelypredicting the thermodynamic effects on cavitating flows. The surrogate-based global sensitivity analysis of liquid nitrogen cavitatingflow suggests that ρv, Cl and L could significantly influence temperature drop and cavity structure in the existing numerical framework,while ρv plays the dominant role on temperature drop when properties vary with changing temperature. The liquid viscosity ml slightlyaffects the flow structure but hardly affects the temperature distribution.

An Epidemic Model of Information Dissemination in Mobile Social Networks

Wang Weiguo,Chu Chen,Liu Jinzhuo,Li Tairan 보안공학연구지원센터(IJUNESST) 2015 International Journal of u- and e- Service, Scienc Vol.8 No.1

In this paper, we propose a new model for information dissemination in mobile social networks. The dynamic equation of information dissemination is modified. Moreover, we investigate numerically the behavior of the model on a real scale-free social site with the exponent γ =1.08. We find that initial spreaders with big out-degree of can accelerate information dissemination, and the nodes with large in-degree would be easier to be a spreader or to become to stiflers.

Synthesis of polyethylenimine-modified magnetic hydrogel nanocomposite absorbents for heavy metals removal

Tao Wan,Songsong He,Tairan Wang,Jian Wang,Mingrui Yu,Yang Jianbo,Qi Tang 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.11

Polyethylenimine(PEI)-modified magnetic hydrogel nanocomposite absorbents (PEI-mHNAs) were fabricated based on poly(acrylamide-co-acrylic acid) and PEI-modified magnetic nanoparticles by radical copolymerization. FTIR and XRD results preliminarily confirmed the target structure of PEI-mHNAs without destroying the structure of magnetic nanoparticles during modification and radical copolymerization. PEI-mHNAs with many rough porous and interstitial structure had high adsorption capacity of Cu(II) (217mg/g), Cd(II) (232mg/g) and Pb(II) (459mg/g). PEI-mHNAs had the best absorption capacity for heavy metal ions in the synthesis condition of acrylic acid/acrylamide mass ratio of 60 : 40, 0.8% initiator, AA neutralization degree of 70%, 0.75% crosslinker, and 15% PEImodified magnetic nanoparticles. Moreover, PEI-mHNAs had good magnetic responsiveness, high thermal stability and reusability, which make it a potential application in removing heavy metal ions from the contaminated wastewater.

Combined experimental and computational investigation of the cavitating flow in an orifice plate with special emphasis on surrogate-based optimization method

Xianlin Li,Biao Huang,Tairan Chen,Ying Liu,Sicong Qiu,Jing Zhao 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.1

We investigated the influence of geometrical parameters of the orifice plate on the cavitation structures, and optimized these parameters by using a surrogate-based model with special emphasis on the concentration of hydroxyl radical released. The results show that for the orifice plate of the hydrodynamic cavitation system, the possible location of the inception of the cavity spreads to throat and divergent section of the venturi geometry. Based on the surrogate model and global sensitivity assessment, the diameter of throat D t and diameter of inlet D in significantly influenced the size of the cavity, while the length of throat L t had little effect on both cavitation intensity and flow rate. It should be noted that when L t is decreased, the size of cavity would be slightly decreased but the flow rate increased clearly. The increase of the diverging section is in favor of the size of cavity. By comparing the experimental measurements on the concentration of Methylene blue, the optimum geometry of the orifice plate for best cavitational activity is proposed.

Size-dependent dynamic stability of a FG polymer microbeam reinforced by graphene oxides

Yuewu Wang,Ke Xie,Tairan Fu 국제구조공학회 2020 Structural Engineering and Mechanics, An Int'l Jou Vol.73 No.6

The dynamic stability of a functionally graded polymer microbeam reinforced by graphene oxides subjected to a periodic axial force is investigated. The microbeam is assumed to rest on an elastic substrate and is subjected to various immovable boundary restraints. The weight fraction of graphene oxides nanofillers is graded across the beam thickness. The effective Young's modulus of the functionally graded graphene oxides reinforced composite (FG-GORC) was determined using modified Halpin–Tsai model, with the mixture rule used to evaluate the effective Poisson's ratio and the mass density. An improved third order shear deformation theory (TSDT) is used in conjunction with the Chebyshev polynomial-based Ritz method to derive the Mathieu-Hill equations for dynamic stability of the FG-GORC microbeam, in which the scale effect is taken into account based on modified couple stress theory. Then, the Mathieu-Hill equation was solved using Bolotin's method to predict the principle unstable regions of the FG-GORC microbeams. The numerical results show the effects of the small scale, the graphene oxides nanofillers as well as the elastic substrate on the dynamic stability behaviors of the FG-GORC microbeams.

Numerical simulations and surrogate-based optimization of cavitation performance for an aviation fuel pump

Xing’an Zhao,Biao Huang,Tairan Chen,Guoyu Wang,Deming Gao,Jing Zhao 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.2

We used computational modeling to investigate the cavitation performance of an aviation fuel pump, and optimize structural parameters using the surrogate-based method. In the numerical simulation, a rotation-curvature correction was adapted to the k-ε turbulence model, and a four-component surrogate fuel was selected to reproduce the physical properties of the China RP-3 kerosene. Then the performance of the aviation fuel pump was predicted. In the optimization, based on the series of the numerical results, Surrogate-based analysis and optimization (SBAO) was used to optimize the structural parameters of the fuel pump (the variation of the outlet blade angle for the inducer △β b1 and the variation of the inlet blade angle for the impeller △β b2 ). The results show that the prediction of cavitation performance agrees well with the experimental data. The results show that cavitation areas are mainly distributed in the inlet of the inducer. The volume of cavities grows with the decreasing NPSHa. The head of the fuel pump has a sudden head-drop when NPSHa ≤ 5.64 m. Furthermore, the surrogate-based approach is available in structural optimization of the fuel pump. The cavitation performance of the optimized pump improved about 22 % with a little drop of head coefficient when △β b1 = 4.33° and △β b2 = 3.24°. The numerical approach employed in this paper can accurately predict the cavitating flow of the high rotating speed fuel pump and the surrogate-based method is available in the structural optimization for a better cavitation performance.

Role of Tie Strength in Information Dissemination in Mobile Social Networks

Wang Weiguo,Chu Chen,Liu Jinzhuo,Li Tairan 보안공학연구지원센터 2015 International Journal of u- and e- Service, Scienc Vol.8 No.3

In this paper, we propose a new model for information dissemination in mobile social networks, in which the infectious probability is defined as a function of the homogeneity and heterogeneity between nodes. Moreover, we investigate numerically the behavior of the model on a real scale-free social site with the exponent γ =1.08. We find that weak ties between nodes play an important role in information dissemination process. Specially, selecting weak ties preferentially can make information spread faster and wider, and the efficiency of diffusion will be greatly affected after removing them.

점토점결폐주물사를 활용한 메조포러스 실리카 제조 연구

조우리 ( Woori Cho ),김수향 ( Su-hyang Kim ),여태연 ( Tairan Yu ),이정한 ( Jung Han Lee ),박지수 ( Ji Soo Park ),이재영 ( Jai-young Lee ) 한국폐기물자원순환학회 2022 한국폐기물자원순환학회 심포지움 Vol.2022 No.1

Heavy mineral analysis to identify sediment provenance in the Dan River drainage, China

Qingpeng Meng,Wen Zhang,Jing Zhang,Zhaoyu Zhang,Tairan Wu 한국지질과학협의회 2016 Geosciences Journal Vol.20 No.4

Identifying the provenance of sediments carried by modern rivers can provide information on earth surface processes and help us to interpret geological history more clearly. The types and distribution patterns of surface sediments deposited in river systems are determined mainly by the fluvial flux and weathering of the proximal source rocks. In this paper, analysis of the heavy mineral content of 99 surface sediment samples was used to identify the source of the sediments carried by the Dan River in China. The objectives of this study are to: (1) determine the characteristics and distribution of the sediments, and (2) identify and classify the various depositional areas according to their differing source areas. The Dan River is divided into the lower, middle, and upper reaches to investigate the spatial distribution of heavy minerals. The main minerals detected were amphiboles, pyroxene, epidote, garnet, tourmaline, zircon, apatite, rutile, sphene, anatase, pyrite, and ilmenite. Generally, ilmenite (0.7% to 69.1%), amphibole (0% to 93.6%), epidote (0% to 53.3%), garnet (0% to 36.7%) and pyroxene (0% to 42.0%) were the most frequent detrital heavy minerals in the studied river sections. The Dan River and its tributaries are characterized with respect to their heavy mineral assemblages and heavy mineral indexes. Six depositional areas are distinguished and classified as Depositional area A (the Laoguan, Qi, and Xian rivers), Depositional area B (the Qingyou and Wuguan rivers), Depositional area C (the Laojun River), Depositional area D (the upper reaches of the Dan River), Depositional area E (the Yinhua River), and Depositional area F (the Tao River). The provenance study indicated that the sediments were derived mainly from the proximal exposed rocks. Sediments in the middle reaches of the Dan River were derived from Depositional areas B, C, and E, whereas sediments in the lower reaches were derived mainly from the local rocks along the river. Similar heavy mineral assemblages were obtained from Danjiangkou Reservoir and Depositional area A, especially for the Laoguan River, indicating the significant influence of Depositional area A on the reservoir.