Study on Simulation of the Building Fires Using an Advanced New Model

2013 ◽  
Author(s):  
Zuhua Shan ◽  
Fenglei Niu ◽  
Yan Zhang ◽  
Pengfei Hao
Keyword(s):  
Nuclear Power ◽  
Radiation Heat Transfer ◽  
Good Prediction ◽  
Ambient Fluid ◽  
Building Fires ◽  
New Model ◽  
One Dimensional ◽  
Interface Location ◽  
Significant Attention ◽  
Upper Layer Temperature

Building fires have been paid significant attention in the nuclear power station’s safety. In order to study the stratification phenomena of the enclosure fires and predict the interface location of upper hot layer filled with smoke and lower cold layer filled with fresh air and upper layer temperature of enclosure fires, an advanced new model is used in this paper, in which one–dimensional differential equations are used to describe the temperature and species distributions of the ambient fluid. And the results of Steckler’s fire experiments are used to compare with the simulation results of five sets of experiment using the new model. The results indicate that this model gives a very good prediction for the location of the interface and the upper layer temperature, especially for the cases with a lower fire heat release rate, even without considering the radiation heat transfer.

scholarly journals Quantifying photoinduced carriers transport in exciton–polariton coupling of MoS2 monolayers

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Min-Wen Yu ◽  
Satoshi Ishii ◽  
Shisheng Li ◽  
Ji-Ren Ku ◽  
Jhen-Hong Yang ◽  
...  
Keyword(s):  
Electronic Energy ◽  
Plasmonic Nanostructures ◽  
Transition Metal Dichalcogenide ◽  
Metallic Nanoparticle ◽  
Rabi Splitting ◽  
One Dimensional ◽  
Induced Dipole ◽  
Mos2 Monolayers ◽  
Plasmon Polaritons ◽  
Significant Attention

AbstractExciton–polariton coupling between transition metal dichalcogenide (TMD) monolayer and plasmonic nanostructures generates additional states that are rich in physics, gaining significant attention in recent years. In exciton–polariton coupling, the understanding of electronic-energy exchange in Rabi splitting is critical. The typical structures that have been adopted to study the coupling are “TMD monolayers embedded in a metallic-nanoparticle-on-mirror (NPoM) system.” However, the exciton orientations are not parallel to the induced dipole direction of the NPoM system, which leads to inefficient coupling. Our proposed one-dimensional plasmonic nanogrooves (NGs) can align the MoS2 monolayers’ exciton orientation and plasmon polaritons in parallel, which addresses the aforementioned issue. In addition, we clearly reveal the maximum surface potential (SP) change on intermediate coupled sample by the photo-excitation caused by the carrier rearrangement. As a result, a significant Rabi splitting (65 meV) at room temperature is demonstrated. Furthermore, we attribute the photoluminescence enhancement to the parallel exciton–polariton interactions.

Long waves in a straight channel with non-uniform cross-section

2015 ◽  
Vol 770 ◽  
pp. 156-188 ◽  
Author(s):  
Patricio Winckler ◽  
Philip L.-F. Liu
Keyword(s):  
Boundary Layer ◽  
Wave Propagation ◽  
Cross Section ◽  
Three Dimensional ◽  
Channel Cross Section ◽  
Cross Sectional ◽  
New Model ◽  
One Dimensional ◽  
Uniform Channel ◽  
The Cross

A cross-sectionally averaged one-dimensional long-wave model is developed. Three-dimensional equations of motion for inviscid and incompressible fluid are first integrated over a channel cross-section. To express the resulting one-dimensional equations in terms of the cross-sectional-averaged longitudinal velocity and spanwise-averaged free-surface elevation, the characteristic depth and width of the channel cross-section are assumed to be smaller than the typical wavelength, resulting in Boussinesq-type equations. Viscous effects are also considered. The new model is, therefore, adequate for describing weakly nonlinear and weakly dispersive wave propagation along a non-uniform channel with arbitrary cross-section. More specifically, the new model has the following new properties: (i) the arbitrary channel cross-section can be asymmetric with respect to the direction of wave propagation, (ii) the channel cross-section can change appreciably within a wavelength, (iii) the effects of viscosity inside the bottom boundary layer can be considered, and (iv) the three-dimensional flow features can be recovered from the perturbation solutions. Analytical and numerical examples for uniform channels, channels where the cross-sectional geometry changes slowly and channels where the depth and width variation is appreciable within the wavelength scale are discussed to illustrate the validity and capability of the present model. With the consideration of viscous boundary layer effects, the present theory agrees reasonably well with experimental results presented by Chang et al. (J. Fluid Mech., vol. 95, 1979, pp. 401–414) for converging/diverging channels and those of Liu et al. (Coast. Engng, vol. 53, 2006, pp. 181–190) for a uniform channel with a sloping beach. The numerical results for a solitary wave propagating in a channel where the width variation is appreciable within a wavelength are discussed.

Combined hydraulic and biological modelling and full-scale validation of SBR process

2002 ◽  
Vol 45 (6) ◽  
pp. 219-228 ◽  
Author(s):  
J. Keller ◽  
Z. Yuan
Keyword(s):  
Scale Validation ◽  
Experimental Period ◽  
Full Scale ◽  
Good Prediction ◽  
Batch Reactors ◽  
Biological Processes ◽  
Sequencing Batch Reactors ◽  
One Dimensional ◽  
Biological Modelling ◽  
Soluble Components

The biological reactions during the settling and decant periods of Sequencing Batch Reactors (SBRs) are generally ignored as they are not easily measured or described by modelling approaches. However, important processes are taking place, and in particular when the influent is fed into the bottom of the reactor at the same time (one of the main features of the UniFed process), the inclusion of these stages is crucial for accurate process predictions. Due to the vertical stratification of both liquid and solid components, a one-dimensional hydraulic model is combined with a modified ASM 2d biological model to allow the prediction of settling velocity, sludge concentration, soluble components and biological processes during the non-mixed periods of the SBR. The model is calibrated on a full-scale UniFed SBR system with tracer breakthrough tests, depth profiles of particulate and soluble compounds and measurements of the key components during the mixed aerobic period. This model is then validated against results from an independent experimental period with considerably different operating parameters. In both cases, the model is able to accurately predict the stratification and most of the biological reactions occurring in the sludge blanket and the supernatant during the non-mixed periods. Together with a correct description of the mixed aerobic period, a good prediction of the overall SBR performance can be achieved.

Two-Dimensional Model for Wave-Induced Pore Pressure Accumulation in Marine Sediments

2013 ◽  
Author(s):  
Hongyi Zhao ◽  
Dong-Sheng Jeng ◽  
Huijie Zhang ◽  
Jisheng Zhang
Keyword(s):  
Pore Pressure ◽  
Marine Sediments ◽  
Wave Motion ◽  
Present Model ◽  
Two Dimensional ◽  
New Model ◽  
One Dimensional ◽  
Wave Cycle ◽  
Previous Solution ◽  
Wave Induced

In this paper, a two-dimensional (2D) porous model is established to investigate the predication of the wave-induced pore pressure accumulations in marine sediments. In the new model, the VARANS equation is used as the governing equation for the wave motion, while the Biot’s consolidation theory is used for porous seabed. The present model is verified with the previous experimental data [1] and provides a better prediction of pore pressure accumulation than the previous solution [2]. With the new model, a 2D liquefied zone is formed at the beginning of the process, and then gradually move down. After a certain wave cycle (for example, 30 wave cycles in the numerical example), the liquefaction zone will become one-dimensional (1D) and continuously move down and eventually approaches to a constant. Numerical results also conclude the maximum liquefaction depth increases as wave height increases and in shallow water.

Heat-Loss Calculations in a SCWR Fuel-Channel

2010 ◽  
Author(s):  
Wargha Peiman ◽  
Eugene Saltanov ◽  
Kamiel Gabriel ◽  
Igor Pioro
Keyword(s):  
Heat Transfer ◽  
Heat Loss ◽  
Nuclear Power ◽  
Heat Losses ◽  
Heat Transfer Analysis ◽  
Operating Pressure ◽  
Total Heat Loss ◽  
Fuel Channel ◽  
One Dimensional ◽  
Heated Length

The objective of this paper is to calculate heat losses from a CANDU-6 fuel-channel while modifying it according to the specified operating pressure and temperature conditions of SuperCritical Water-cooled Reactors (SCWRs). Heat losses from the coolant to the moderator are significant in a SCWR because of high operating temperatures (i.e., 350–625°C). This has adverse effects on the overall thermal efficiency of the Nuclear Power Plant (NPP), so it is necessary to determine the amount of heat losses from fuel-channels proposed for SCWRs. Inconel-718 was chosen as a pressure tube (PT) material and PT minimum required thickness was calculated in accordance with the coolant’s maximum operating pressure and temperature. The heat losses from the fuel-channel were calculated along the heated length of the fuel-channel. Steady-state one-dimensional heat-transfer analysis was conducted, and programming in MATLAB was performed. The fuel-channel was divided into small segments and for each segment thermal resistances of the fuel-channel components were analyzed. Further, the thermophysical properties of the coolant, annulus gas, and moderator were retrieved from the NIST REFPROP software. The analysis outcome resulted in a total heat loss of 29.3 kW per fuel-channel when the pressure of the annulus gas was 0.3 MPa.

scholarly journals Comment on “New Model System for a One-Dimensional Electron Liquid: Self-OrganizedAtomic Gold Chains on Ge(001)”

2009 ◽  
Vol 103 (20) ◽  
Author(s):  
Arie van Houselt ◽  
Daan Kockmann ◽  
Tijs F. Mocking ◽  
Bene Poelsema ◽  
Harold J. W. Zandvliet
Keyword(s):  
Model System ◽  
Dimensional Electron ◽  
New Model ◽  
One Dimensional

Directional Control of Radiation Heat Transfer by V-Groove Cavities—Collimation of Energy in Direction Normal to Cavity Opening

1980 ◽  
Vol 102 (3) ◽  
pp. 563-567 ◽  
Author(s):  
H. Masuda
Keyword(s):  
Heat Transfer ◽  
Radiation Heat Transfer ◽  
Geometrical Parameters ◽  
Radiation Heat ◽  
New Model ◽  
Directional Control ◽  
Cavity Opening ◽  
Radiative Characteristics

To improve the V-groove cavity devised for directional control of radiation heat transfer, a new model with a black fin provided on the cavity base is proposed. The radiative characteristics of the new model are theoretically offered comparing two typical constitutional forms—symmetrical and asymmetrical. It is evident that the fin helps accelerate radiation heat transfer from the V-groove and promote its collimation. The effects can be further enhanced by carefully choosing the various geometrical parameters. The new V-groove cavity proposed would probably be evaluated as a favorable directional surface. The direction of energy collimation can be altered by using the asymmetrical groove cavity.

scholarly journals Station Black-Out Analysis with MELCOR 1.8.6 Code for Atucha 2 Nuclear Power Plant

2012 ◽  
Vol 2012 ◽  
pp. 1-17 ◽  
Author(s):  
Analia Bonelli ◽  
Oscar Mazzantini ◽  
Martin Sonnenkalb ◽  
Marcelo Caputo ◽  
Juan Matias García ◽  
...  
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Heavy Water ◽  
Nuclear Power ◽  
Failure Time ◽  
Thermal Power ◽  
Radiation Heat Transfer ◽  
Primary System ◽  
Water Release ◽  
Plant Safety

A description of the results for a Station Black-Out analysis for Atucha 2 Nuclear Power Plant is presented here. Calculations were performed with MELCOR 1.8.6 YV3165 Code. Atucha 2 is a pressurized heavy water reactor, cooled and moderated with heavy water, by two separate systems, presently under final construction in Argentina. The initiating event is loss of power, accompanied by the failure of four out of four diesel generators. All remaining plant safety systems are supposed to be available. It is assumed that during the Station Black-Out sequence the first pressurizer safety valve fails stuck open after 3 cycles of water release, respectively, 17 cycles in total. During the transient, the water in the fuel channels evaporates first while the moderator tank is still partially full. The moderator tank inventory acts as a temporary heat sink for the decay heat, which is evacuated through conduction and radiation heat transfer, delaying core degradation. This feature, together with the large volume of the steel filler pieces in the lower plenum and a high primary system volume to thermal power ratio, derives in a very slow transient in which RPV failure time is four to five times larger than that of other German PWRs.

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