检索结果-南通市图书馆

Development of coNTHAC-3D and hydrogen distribution analysis of HPR1000

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2024年第2期35卷 210-221页

作者： Hui Wang Jing-Jing Li Yuan Chang Gong-Lin Li Ming Ding China Nuclear Power engineering co.ltd. Beijing 100084China Fundamental Science on Nuclear Safety and Simulation Technology Laboratory Harbin 100049China

An in-house code,coNTHAC-3D,was developed to calculate and analyze thermal-hydraulic phenomena in containments during severe ***-3D is a three-dimensional computational fluid dynamics code that can be applied to predict gas flow,diffusion,and steam condensation in a containment during a severe hypothetical accident,as well as to obtain an estimate of the local hydrogen concentration in various zones of the ***-3D was developed using multiple models to simulate the features of the proprietary systems and equipment of HPR1000 and ACP100,such as the passive cooling system,passive autocatalytic recombiners and the passive air cooling *** validate coNTHAC-3D,a GX6 test was performed at the Battelle Model containment *** hydrogen concentration and temperature monitored by the GX6 test are accurately predicted by ***,the hydrogen distribution in the HPR1000 containment during a severe accident was *** results show that the hydrogen removal rates calculated using coNTHAC-3D for different types of PARs agree well with the theoretical values,with an error of less than 1%.As the accident progresses,the hydrogen concentration in the lower compartment becomes higher than that in the large space,which implies that the lower compartment has a higher hydrogen risk than the dome and large space at a later stage of the *** amount of hydrogen removed by the PARs placed on the floor of the compartment is small;therefore,raising the installation height of these recombiners appropriately is ***,we do not recommend installing all autocatalytic recombiners at high *** study findings in regard to the hydrogen distribution in the HPR1000 containment indicate that coNTHAC-3D can be applied to the study of hydrogen risk containment.

关键词： Hydrogen risk mitigation Pressurized water reactor HPR1000 thermal hydraulic coNTHAC-3D

Finite-difference time-domain modeling of curved material interfaces by using boundary condition equations method

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2016年第9期25卷 198-206页

作者：卢佳周怀春 Department of thermal engineering Tsinghua University

To deal with the staircase approximation problem in the standard finite-difference time-domain（FDTD） simulation,the two-dimensional boundary condition equations（BCE） method is proposed in this *** the BCE method,the standard FDTD algorithm can be used as usual,and the curved surface is treated by adding the boundary condition ***,while maintaining the simplicity and computational efficiency of the standard FDTD algorithm,the BCE method can solve the staircase approximation *** BCE method is validated by analyzing near field and far field scattering properties of the PEC and dielectric *** results show that the BCE method can maintain a second-order accuracy by eliminating the staircase approximation ***,the results of the BCE method show good accuracy for cylinder scattering cases with different permittivities.

关键词： finite-difference time-domain curved surface staircase error boundary condition equation

Mathematical Model for fluid Flow and Heat Transfer in the cooling Shaft of coke Dry Quenching Unit

在线全文

学校读者我要写书评

暂无评论

Journal of thermal Science 2002年第1期11卷 65-73页

作者： Huafei Liu Xinxin Zhang Lie Xu Mingdeng Wang Department of thermal engineering University of Science&Technology BeijingBeijing100083China Anshan Hua Tai CDQ engineering&Technology co.ltd. Anshan114002China coking&Gas Making Section Anshean coking&Refractor y engineering consulting Crop.Ansban 114002China

A mathematical model based on non-Darcian flow and two-phase model is developed for fluid flow and heat transfer in the cooling shaft of coke Dry Quenching (CDQ) unit. The potential flow model is employed to simulate coke descending. Governing equations are solved by the SIMPLE algorithm on the collocated, non-orthogonal and body-fitted grids. The velocity of circulating gas and the temperature of coke and gas are obtained to study the effects of coke size distribution on flow and heat transfer behavior in the cooling shaft. It is found that the non-uniformity of gas velocity and the unevenness of coke temperature in the radial direction can be reduced if coke size distribution is improved. The gas velocity field and the temperature distribution of coke and gas are presented.

关键词： coke dry quenching(CDQ) porous media non-Darcian flow two-phase model non-orthogonal grid

Analysis of the Pump-turbine S Characteristics Using the Detached Eddy Simulation Method

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical engineering 2015年第1期28卷 115-122页

作者： SUN Hui XIAO Ruofu WANG Fujun XIAO Yexiang LIU Weichao college of Water Resources and Civil engineering China Agricultural University State Key Laboratory of Hydroscience and engineering & Department of thermal engineering Tsinghua University Dongfang Electric Machinery co. Ltd

Current research on pump-turbine units is focused on the unstable operation at off-design conditions, with the characteristic curves in generating mode being S-shaped. Unlike in the traditional water turbines, pump-turbine operation along the S-shaped curve can lead to difficulties during load rejection with unusual increases in the water pressure, which leads to machine vibrations. This paper describes both model tests and numerical simulations. A reduced scale model of a low specific speed pump-turbine was used for the performance tests, with comparisons to computational fluid dynamics（CFD） results. Predictions using the detached eddy simulation（DES） turbulence model, which is a combined Reynolds averaged Naviers-Stokes（RANS） and large eddy simulation（LES） model, are compared with the two-equation turbulence mode results. The external characteristics as well as the internal flow are for various guide vane openings to understand the unsteady flow along the so called S characteristics of a pump-turbine. comparison of the experimental data with the CFD results for various conditions and times shows that DES model gives better agreement with experimental data than the two-equation turbulence model. For low flow conditions, the centrifugal forces and the large incident angle create large vortices between the guide vanes and the runner inlet in the runner passage, which is the main factor leading to the S-shaped characteristics. The turbulence model used here gives more accurate simulations of the internal flow characteristics of the pump-turbine and a more detailed force analysis which shows the mechanisms controlling of the S characteristics.

关键词： pump-turbine S-shaped characteristics detached eddy simulation(DES) numerical analysis

Preparation of ferronickel from nickel laterite via coal-based reduction followed by magnetic separation

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2018年第7期25卷 744-751页

作者： Lun-wei Wang Xue-ming Mei Liu Zhi-xiong You Xue-wei Chen-guang Bai college of materials science and engineering chongqing universityChongqing 400044China engineer of cisdi thermal&environmental engineering co. ltd.Chongqing 401122China

The sticking phenomenon between molten slag and refractory is one of the crucial problems when preparing ferronickel from laterite ore using rotary hearth fulnace or rotary kiln processes. This study aims to ameliorate sticking problems by using silicon dioxide （SiO2） to adjust the melting degree of file briquette during reduction roasting. Thermodynamic analysis indicates that the melting temperature of the slag gradually increases with an increase in the SiO2 proportion （SiO2/（SiO2 ＋ A1203 ＋ MgO） mass ratio）. Experimental validations also prove that the briquette retains its original shape when the SiO2 proportion is greater than 75wt%, and sticking problems axe avoided during reduction. A ferronickel product with 8.33wt% Ni and 84.71wt% Fe was prepared via reductive roasting at 1500~C for 90 min with a SiO2 proportion of 75wt% and a C/O molar ratio of 1.0 followed by dry magnetic separation; the corresponding recoveries of Ni and Fe reached 75.70% and 77.97%, respectively. The micro stxucture and phase txmlsformation of reduced briquette reveals that the aggregation and growth of ferroinckel particles were not significantly affected after adding SiO2 to the reduction process.

关键词： nickel laterite caxbot^ermal reduction ferronickel magnetic separation

Microstructural evolution of a Ni-co based superalloy during hot compression atγ'sub-/super-solvus temperatures

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2021年第18期77卷 66-81页

作者： Peng Liu Rui Zhang Yong Yuan Chuanyong Cui Faguang Liang Xi Liu Yuefeng Gu Yizhou Zhou Xiaofeng Sun Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and engineering University of Science and Technology of ChinaShenyang 110016China Xi'an thermal Power Research Institute co.ltd. Xi'an 710032China

The effects of strain rate on the microstructural evolution and deformation mechanism of a Ni-co based superalloy were investigated by isothermal compression tests performed atγ'sub-solvus(1090℃)andγ'super-solvus temperatures(1150℃)with a wide strain rate range from 0.001 to 10 s^(-1)under a true strain of *** backscatter diffraction(EBSD),electron channeling contrast imaging(ECCI)and transmission electron microscope(TEM)techniques were used to characterize the *** results revealed that the dynamic recrystallization(DRX)volume fraction increased and stored energy of theγ'matrix grains decreased with increasing the strain rate duringγ'sub-solvus temperature deformation,while the opposite phenomena were observed duringγ'super-solvus temperature *** comprehensive effect of initial grain size,primaryγ'phase,twins and adiabatic temperature rise led to these *** primaryγ'particles undergone the deformation behavior within itself and obviously accelerated the DRX of the *** microstructural evolution proved that discontinuous dynamic recrystallization(DDRX)was the dominant mechanism during the hot deformation carried out at bothγ'sub-solvus andγ'super-solvus ***γ'particles obviously accelerated the nucleation step and retarded the growth step of DDRX duringγ'sub-solvus temperature ***,the acceleration effect of primaryγ'particles on DDRX increased with the increase of strain *** dynamic recrystallization(CDRX)was confirmed to be an assistant mechanism duringγ'super-solvus temperature deformation and was promoted with the increase of strain rate.

关键词： Ni-co based superalloy Strain rate Primaryγ'precipitates Dynamic recrystallization Microstructural evolution

co-pyrolysis characteristics of typical components of waste plastics in a falling film pyrolysis reactor

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical engineering 2018年第10期26卷 2176-2184页

作者： Zechen Jin Lijie Yin Dezhen Chen Yuanjie Jia Jun Yuan Yuyan Hu thermal and Environmental engineering Institute Tongji University Shanghai 200092 China Shanghai Municipal engineering Design Institute (Group) co. Ltd. Shanghai 200092 China

Waste plastics mainly come from MSW and usually exist in the form of mixed plastics. During the co-pyrolysis process of mixed plastics, various plastic components have different physicochemical properties and reaction mechanisms. considering the high viscosity and low thermal conductivity of molten plastics, a falling film pyrolysis reactor was selected to explore the rapid co-pyrolysis process of typical plastic components(PP, PE and PS).The oil and gas yields and the compositions of pyrolysis products of the three components under different ratios at pyrolysis temperatures were analyzed to explore the co-pyrolysis characteristics of PP, PE, and PS. The study is of great significance to the recycling of waste plastics.

关键词： co-pyrolysis Falling film reactor Waste plastics

Working fluid selection based on critical temperature and water temperature in organic Rankine cycle

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2015年第1期58卷 138-146页

作者： LI XinGuo ZHAO WenJing LIN DieDie ZHU Qiang Department of thermal engineering School of Mechanical Engineering Tianjin University

This paper examines the thermal performance of working fluids in the entire evaporation temperature region up to near-critical temperature of working fluids in the organic Rankine cycle(ORC).The variation and tendency of the net power output with water temperature and correlated with the critical temperature of working fluids is *** characteristic curves of the net power output at particular water temperature(Tw_turn,Tw_app,Tw_tran and Tw_up)and their temperature difference(△T_turn=Tw_turn△Tcr,△T_app=Tw_app△Tcr)are obtained to evaluate the working *** curve at"applicable water temperature(Tw_app)"is a demarcation to differentiate the net power output from low to ***"upper water temperature(Tw_up)"is an upper limit of the water temperature to yield the higher net power output.A relation is built that the suitable water temperature is within the Tw_app and Tw_up of the working fluid.

关键词： organic Rankine cycle(ORC) thermal performance working fluid selection critical temperature of working fluid water temperature

An Improved Prediction Equation of Refrigerants Surface Tension Based on the Principle of corresponding States

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2014年第4期30卷 681-684页

作者： LI Wenzhe BI Shengshan ZHAO Guanjia WU Jiangtao Key Laboratory of thermal fluid Science and engineering of Ministry of Education Xi 'an Jiaotong University Xi 'an 710049 P. R. China

The surface tensions of 21 pure refrigerants have been predicted by a new improved equation based on the principle of corresponding states with double referenced *** average absolute deviation between the calculated surface tensions from the equation and the experimental result is-0.015 mN/*** surface tensions of 9 binary mixtures were calculated in consideration of certain mixing *** the average absolute deviation between the calculated surface tensions from the equation and the experimental result is-0.251 mN/*** new improved prediction equation can be used for calculating the surface tension of environmental friendly refrigerants.

关键词： Surface tension corresponding state Refrigerant Mixture