Numerical Prediction and Optimization of Depressurized Sodium-Water Reaction Experiment With Counter-Flow Diffusion Flame

2008 ◽  
Author(s):  
Akira Yamaguchi ◽  
Takashi Takata ◽  
Hiroyuki Ohshima ◽  
Yoshitaka Kohara
Keyword(s):  
Diffusion Flame ◽  
Liquid Sodium ◽  
Counter Flow ◽  
Pressurized Water ◽  
Sodium Fast Reactor ◽  
Transfer Tube ◽  
Reaction Region ◽  
Long Time ◽  
Design Basis Accident ◽  
Physical And Chemical

Sodium-water reaction (SWR) is a design basis accident of a Sodium Fast Reactor (SFR). A breach of the heat transfer tube in a steam generator (SG) results in contact of liquid sodium with water. Typical phenomenon is that the pressurized water blows off, vaporizes and mixes with the liquid sodium. In this paper, a new computer program has been developed and the SWR in a counter-flow diffusion flame is studied by a numerical simulations and an experiment. The experiment is designed with the numerical simulation so that the stable reaction flame is maintained for long time and physical and chemical quantities are measured. From the comparison of analysis and experiment, there exist discrepancies that may be caused by the assumptions of chemical reaction. Hence, a new experiment is proposed to enhance the measurement accuracy and to investigate the reason of the disagreement. The authors propose a depressurized experiment. With the depressurization, it is expected the flame location can be controlled and the reaction region becomes thicker because of decrease in reactant gas density.

Sodium-Water Reaction Elucidation With Counter-Flow Diffusion Flame Experiment and Its Numerical Simulation

2010 ◽  
Author(s):  
Akira Yamaguchi ◽  
Takashi Takata ◽  
Hiroyuki Ohshima ◽  
Joji Sogabe ◽  
Yoshihiro Deguchi ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Diffusion Flame ◽  
Exothermic Reaction ◽  
Reaction Model ◽  
Liquid Sodium ◽  
Counter Flow ◽  
Pressurized Water ◽  
Sodium Fast Reactor ◽  
Transfer Tube ◽  
Design Basis Accident

Sodium-water reaction (SWR) is a design basis accident of a Sodium Fast Reactor (SFR). A breach of the heat transfer tube in a steam generator (SG) results in contact of liquid sodium with water. Typical phenomenon is that the pressurized water blows off, vaporizes and mixes with the liquid sodium. The consequence of the accident are: thermal-hydraulic and chemical impact on the heat transport equipment and structure induced by the heat of exothermic reaction and caustic reaction product. The purpose of the present paper is to delineate the mechanism and process of the SWR by a counter-flow diffusion flame experiment and a numerical simulation. Based on the numerical simulation, the most appropriate and optimum condition in which stable and continuous diffusion flame of sodium and water vapor is obtained. Key idea is to perform the experiment in a depressurized reaction vessel. According to the experiment, spatial distributions of chemical reactants and products, temperature and particles are measured in detail. The characteristics of the SWR are explained from the present study and the chemical reaction model currently used in the analytical tool of the SWR is appropriate.

Numerical Prediction and Optimization of Depressurized Sodium-Water Reaction Experiment With Counterflow Diffusion Flame

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Akira Yamaguchi ◽  
Takashi Takata ◽  
Hiroyuki Ohshima ◽  
Yoshitaka Kohara ◽  
Yoshihiro Deguchi
Keyword(s):  
Numerical Simulation ◽  
Chemical Reaction ◽  
Diffusion Flame ◽  
Safety Evaluation ◽  
Liquid Sodium ◽  
Pressurized Water ◽  
Transfer Tube ◽  
Reaction Region ◽  
Long Time ◽  
Counterflow Diffusion Flame

Sodium-water reaction (SWR) is a design basis accident of a sodium-cooled fast reactor (SFR). A breach of the heat transfer tube in a steam generator results in contact of liquid sodium with water. Typical phenomenon is that the pressurized water blows off, vaporizes, and mixes with the liquid sodium. It is necessary to quantify the SWR phenomena in the safety evaluation of the SFR system. In this paper, a new computer program has been developed and the SWR in a counterflow diffusion flame is studied by a numerical simulation and an experiment. The experiment is designed based on the numerical simulation so that the stable reaction flame is maintained for a long time and physical and chemical quantities are measured. From the comparison of the analysis and the experiment, there exist discrepancies that may be caused by the assumptions of the chemical reaction. Hence, a new experiment is proposed to enhance the measurement accuracy and to investigate the reason of the disagreement. The authors propose a depressurized experiment and show the preliminary result of the experiment. It is found that a stable chemical reaction flame is formed. With the depressurization, it is expected that the flame location can be controlled and the reaction region becomes thicker because of decrease in the reactant gas density.

scholarly journals Numerical simulation of the effect of diluents on NOx formation in methane and methyl formate fuels in counter flow diffusion flame

2020 ◽  
Vol 7 (2) ◽  
pp. 140-152
Author(s):  
Patrick Wanjiru ◽  
◽  
Nancy Karuri ◽  
Paul Wanyeki ◽  
Paul Kioni ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Diffusion Flame ◽  
Methyl Formate ◽  
Counter Flow

Triclinic boron nanosheets high-efficient electrocatalysts for water splitting

2021 ◽  
Author(s):  
Maoping Xu ◽  
Rui Wang ◽  
Kan Bian ◽  
Chuang Hou ◽  
Yaxing Wu ◽  
...  
Keyword(s):  
Active Sites ◽  
Theoretical Calculations ◽  
Chemical Properties ◽  
Chemical Vapor ◽  
Energy Storage And Conversion ◽  
High Efficient ◽  
Long Time ◽  
Time Cycle ◽  
Metal Properties ◽  
Physical And Chemical

Abstract Recently, two-dimensional (2D) boron nanosheets have been predicted to exhibit exceptional physical and chemical properties, which is expected to be widely used in advanced electronics, optoelectronic, energy storage and conversion devices. However, the experimental application of 2D boron nanosheets in hydrogen evolution reactiuon (HER) has not been reported. Here, we have grown ultrathin boron nanosheets on tungsten foils via chemical vapor deposition (CVD). The prepared triclinic boron nanosheets are highly crystalline, which perfectly match the structure in the previous theoretical calculations. Notably, the boron nanosheets show excellent HER performance. The Tafel slope is only 64 mV/dec-1 and the nanosheets can maintain good stability under long-time cycle in acidic solution. The improvement of performance is mainly due to the metal properties and a large number of exposed active sites on the boron nanosheets, which is confirmed by first-principle calculations.

scholarly journals Effects of physical and chemical factors on pseudorabies virus activity in vitro

2020 ◽  
Vol 16 (1) ◽  
Author(s):  
Lang Gong ◽  
Qiwei Deng ◽  
Runda Xu ◽  
Chihai Ji ◽  
Heng Wang ◽  
...  
Keyword(s):  
Pseudorabies Virus ◽  
Irradiation Time ◽  
Biological Characteristics ◽  
Economic Losses ◽  
Multiple Factors ◽  
Alkaline Environments ◽  
Long Time ◽  
Chemical Factors ◽  
Physical And Chemical

Abstract Background Pseudorabies (PR) is latent and can persist in infected sows for a long time, and thus, convalescent sows can carry the virus throughout life, causing severe economic losses to farmers and posing a tremendous challenge to PR prevention and control. Here, to investigate the biological characteristics of pseudorabies virus (PRV), a variety of physical and chemical factors were analyzed under controlled conditions. Results The results showed that a high ambient temperature and dry environment led to faster virus inactivation. PRV had a certain resistance to weakly acidic or alkaline environments and was rapidly inactivated in strongly acidic or alkaline environments. The effect of ultraviolet (UV) radiation on PRV activity primarily depended on the frequency, intensity, and irradiation time of the UV exposure. Exposure to sunlight inactivated PRV via multiple factors, including temperature, sunlight intensity, UV intensity, and environmental humidity, and any shielding from sunlight strongly lowered the killing effect. Conventional disinfectants had a good disinfection effect on PRV. Conclusions The biological characteristics of different PRV strains are variable. Generally, the activity of PRV is affected by multiple factors, which can show both synergy and antagonism. Real-world conditions should be taken into consideration to guide pork production.

Physical and chemical aspects of the development of overpressuring in sedimentary environments

Clay Minerals ◽  
1994 ◽  
Vol 29 (4) ◽  
pp. 425-437 ◽  
Author(s):  
P. L. Hall
Keyword(s):  
Fluid Pressure ◽  
Sediment Thickness ◽  
Volume Changes ◽  
Sedimentary Environments ◽  
Vertical Permeability ◽  
Burial Rate ◽  
Long Time ◽  
Physical And Chemical ◽  
First Time ◽  
Applied Stresses

AbstractFluid pressures in argillaceous sediments depend on, inter alia, mechanical stresses, temperature, diagenetic volume changes and permeability. However, the relative influence of the pressuring mechanisms depends critically upon the long time-scale compliance, C, of the overpressured layer.In sediments undergoing first-time burial and currently exposed to their historically maximum applied stresses, C can be relatively large. Here, fluid pressure increases are principally due to mechanical causes, and overpressuring will be associated with undercompaction. The tendency for undercompaction (compaction disequilibrium) depends on the sediment thickness, burial rate and vertical permeability. In other cases, when applied stresses have been reduced by uplift, or when impermeable hard caps or seals have been formed, C may be substantially smaller. Here pore pressures may be predominantly controlled by diagenetic and aquathermal processes, with mechanical (undercompaction) phenomena being relatively less significant.Three-dimensionally sealed overpressured zones may exhibit vertical fluid pressure discontinuities. Within a sealed aquifer, fluid pressures may rise to almost lithostatic values, relieved by episodic fracturing of the seal.

Sign in / Sign up

Export Citation Format

Share Document