Hydrogen combustion in the containment building may be a threat to containment *** in some subcompartments,hydrogen detonation is more easier to happen,which may destroy the containment structure or the safety equipme...
详细信息
Hydrogen combustion in the containment building may be a threat to containment *** in some subcompartments,hydrogen detonation is more easier to happen,which may destroy the containment structure or the safety equipments in the containment. A study has been carried out using the GASFLOW three-dimensional CFD code to evaluate the hydrogen distribution in the subcompartment during a severe *** Chinese 600MW NPP containment is modeling by GASFLOW. The GASFLOW calculation gave detailed results for the spatial distribution of gas concentrations in the reactor coolant pump（RCP） compartment and the steam generator（SG） compartment within containment.
The advanced pressurized water reactor with a tight hexagonal lattice has its potential to improve uranium utilization. With a smaller pitch-to-diameter ratio(p/d) ranging from 1.06 to 1.20, a major problem is the eme...
详细信息
The advanced pressurized water reactor with a tight hexagonal lattice has its potential to improve uranium utilization. With a smaller pitch-to-diameter ratio(p/d) ranging from 1.06 to 1.20, a major problem is the emergency core cooling in a loss-of-coolant accident. The NEPTUN-III and FLORESTAN flooding experiments at PSI and KfK have been performed during the verification period 1985-1990, and the results shows that the reflooding behavior of LWHCR is quite different from that of LWR with higher peak clad temperatures and smaller quench rates. The existing system codes like RELAP5, CATHARE, TRAC may not be able to be used in the calculations of the reflooding phase of LWHCR. Though some efforts have been put into the validation of the improvement of codes, the results are not so good. In this study, the characteristics of the reflooding behavior of tight lattice are pointed out, and the deficiencies of the reflooding models of RELAP5/MOD3 are also fount out after a simulation of the NEPTUN-III reflooding test. The precursory cooling in tight lattice is not effective especially at low reflooding rates (<4cm/s), the droplet enhancement is not significant compared to LWR, and the vapor Reynolds number is much smaller. Finally, a few modifications to RELAP5/MOD3 are made. Compared with the original code, the modified one can better predict the reflooding phase of tight lattice especially the peak clad temperatures at low reflooding rates. More work should be done to deal with the heat transfer characteristics in the transition region of reflooding in tight lattice..
In wireless sensor networks (WSNs), trap coverage has recently been proposed to tradeoff between the availability of sensor nodes and sensing performance. It offers an efficient framework to tackle the challenge of li...
详细信息
Owing to the shortage of traditional fossil energy, at present the use of geothermal energy has aroused people considerable attention. As a kind of clean and renewable geothermal resource, the hot dry rock will be wid...
详细信息
Owing to the shortage of traditional fossil energy, at present the use of geothermal energy has aroused people considerable attention. As a kind of clean and renewable geothermal resource, the hot dry rock will be widely applied. There is a large number of heat energy stored in hot dry rock. But the hot dry rock is usually located in deep-seated rocks of the earth. So it is rather difficult to utilize such deep resources directly. By means of working medium, heat energy could be delivered to ground and used properly. Usually, the heat exchange between medium and hot dry rock is achieved while the working medium flows through the rock crannies. The characteristic and structure of crannies in hot dry rock play a major role in heat transfer. It is very necessary to study characteristics of three-dimensional crannies and heat transfer effect of hot dry rack in order to reasonable development geothermal energy. The natural crannies in hot dry rock are quite narrow which cannot meet the needs of heat transport. The crannies used to heat exchange are usually produced by artificial explosion to obtain enough porosity. According to the distribution types of crannies after artificial explosion, The three-dimensional model of crannies is established, which is related to the identical porosity and variable porosities in different radius direction. In this paper, the hole with ideal shape is used to simulate crannies. The relationship among pressure, flux, velocity of working medium flowing through crannies and porosity are discussed based on fluid mechanics and heat transfer theory. The present study would have guiding significance in development and utilization of geothermal power.
作者：
LI Feng-yu李凤宇LU Gu-bing陆古兵CHEN Zhi陈智College of Naval Architecture&Power
Naval University of Engineering Wuhan 430033 China 海军工程大学 船舶与动力学院湖北 武汉 430033 Science and Technology on Reactor System Design Technology LaboratoryNuclear Power Institute of China Chendu 610041 China 中国核动力研究设计院核反应堆系统设计技术重点实验室四川成都 610041
In this paper, nonlinear dynamic response under loss of coolant accident (LOCA) transient in the nuclear reactor coolant system (RCS) is investigated with ANSYS program. Many nonlinear factors, such as different struc...
详细信息
In this paper, nonlinear dynamic response under loss of coolant accident (LOCA) transient in the nuclear reactor coolant system (RCS) is investigated with ANSYS program. Many nonlinear factors, such as different structural stiffness in tension and compression, gap and plastic strain caused by main pipes' break etc. are considered. The Secondary development of ANSYS is performed to form the customized module for implementing effective parameterized and modular modeling and LOCA nonlinear analysis. Comparison of the results calculated by ANSYS and program-specific shows that the results are generally consistent, but there are some differences locally. According to the experience of transient dynamic analysis, and there are so many non-linear factors in the reactor coolant system, the difference is acceptable. The efficiency of this engineering analysis is improved remarkably with the convenience of input and modeling, viewable layout and automatic creating of reports, when using the customized module based on ANSYS.
A new type of oscillator is presented in paper which integrates the interdigitated electrode (IDE) into conventional piezoceramic oscillator. Some IDE piezoelectric oscillators are prepared from PZT-5 with length=56 &...
详细信息
A new type of oscillator is presented in paper which integrates the interdigitated electrode (IDE) into conventional piezoceramic oscillator. Some IDE piezoelectric oscillators are prepared from PZT-5 with length=56 mm, width=15 mm and thickness=1 mm. The dimensions of IDE are 0.75 mm space and 0.5 mm. The conventional piezoelectric oscillators are also prepared with the same material and dimensions for comparison. The HP4294A High-frequency Impedance Analyzer and DU-20 Temperature-controlled Oil Bath are applied to explore the impedance of oscillator. The effect of temperature on the frequency of oscillator is researched. The results show that IDE piezoelectric oscillators have more resonant frequencies including overtone frequency and anti-resonance frequency. The resonant frequency of oscillators decreases as the temperature increase. The temperature coefficient of resonance frequency of conventional piezoelectric oscillators is -14%. The temperature coefficient of resonance frequency of IDE piezoelectric oscillators is -21%. The temperature stability of conventional piezoelectric oscillators is a little high.
CUDA has become a very popular programming paradigm in parallel computing area. However, very little work has been done for characterizing CUDA kernels. In this work, we measure the thread level performance, collect t...
详细信息
CUDA has become a very popular programming paradigm in parallel computing area. However, very little work has been done for characterizing CUDA kernels. In this work, we measure the thread level performance, collect the basic block level characteristics, and glean the instruction level properties for about 35 programs from CUDA SDK, Parboil, and Rodinia benchmark suites. In addition, we define basic block vectors, synchronization vectors and thread similarity matrix to capture the characteristics of CUDA programs efficiently. We find that CUDA programs have some unique characteristics at each level compared to sequential programs.
The friction resistance under marine conditions is very important to a marine reactorsystem in the ocean. The traditional empirical or semi-empirical relationships were used in thermo-hydraulic system programmes at t...
详细信息
Among the existing CHF models, the bubble crowding model and the liquid sublayer dryout model have been well accepted for subcooled flow boiling. But both of the two models couldn't give explanation about some det...
详细信息
暂无评论