scholarly journals Effects of local non-equilibrium in rapid eutectic solidification. Part 2: modeling versus experimental data

2020 ◽  
Author(s):  
Junfeng Xu ◽  
Peter Galenko
Keyword(s):  
Experimental Data ◽  
Eutectic Solidification ◽  
Non Equilibrium

scholarly journals Performance of Turbulence Models and Near-Wall Treatments in Discrete Jet Film Cooling Simulations

1998 ◽  
Author(s):  
Jeffrey D. Ferguson ◽  
Dibbon K. Walters ◽  
James H. Leylek
Keyword(s):  
Experimental Data ◽  
Film Cooling ◽  
Turbulence Models ◽  
Viscous Sublayer ◽  
Reynolds Stress Model ◽  
Quality Data ◽  
Wall Functions ◽  
First Time ◽  
Near Wall ◽  
Non Equilibrium

For the first time in the open literature, code validation quality data and a well-tested, highly reliable computational methodology are employed to isolate the true performance of seven turbulence treatments in discrete jet film cooling. The present research examines both computational and high quality experimental data for two length-to-diameter ratios of a row of streamwise injected, cylindrical film holes. These two cases are used to document the performance of the following turbulence treatments: 1) standard k-ε model with generalized wall functions; 2) standard k-ε model with non-equilibrium wall functions: 3) Renormalization Group k-ε (RNG) model with generalized wall functions; 4) RNG model with non-equilibrium wall functions: 51 standard k-ε model with two-layer turbulence wall treatment; 6) Reynolds Stress Model (RSM) with generalized wall functions; and 7) RSM with non-equilibrium wall functions. Overall, the standard k-ε turbulence model with the two-layer near-wall treatment, which resolves the viscous sublayer, produces results that are more consistent with experimental data.

Solubility of Impurities and Defect Impurity Interaction In II-VI Semiconductors

1989 ◽  
Vol 161 ◽  
Author(s):  
Y. Marfaing
Keyword(s):  
Experimental Data ◽  
Solubility Limit ◽  
Impurity Interaction ◽  
Light Excitation ◽  
Substitutional Impurities ◽  
Non Equilibrium

ABSTRACTA description of incorporation and solubility limit of substitutional impurities is made using the alloy CdxHgloxTe as a model of analysis and a source of experimental data.Then non-equilibrium incorporation of impurities under light excitation is considered. A model of photo assisted doping is presented which accounts for the high doping efficiency reported for the donor indium in photoassisted grown CdTe.

CFD Predictions of Efficiency for Non-Equilibrium Steam 2D Cascades

2012 ◽  
Author(s):  
Francisco J. Moraga ◽  
Martin Vysohlid ◽  
Andrew G. Gerber ◽  
Natalia Smelova ◽  
Sriram Atheya ◽  
...  
Keyword(s):  
Experimental Data ◽  
Wet Steam ◽  
Equilibrium Models ◽  
Loss Coefficients ◽  
Cfd Analyses ◽  
Non Equilibrium

Most non-equilibrium wet steam CFD analyses in the open literature have concentrated on predicting blade pressure loadings, with very few studies emphasizing turbine efficiencies. One of the few exceptions is the work of Gerber et al. [1]. In light of this, in this paper we present CFD predictions of isokinetic efficiency and Markov Loss coefficients and comparisons with measurements for the 2D cascades of White et al. [2] and Bakhtar et al. [3, 4]. Predictions were obtained using an Eulerian-Eulerian multiphase formulation, which is an extension of General Electric’s proprietary CFD turbomachinery code, TACOMA. The formulation is optimized to capture the thermodynamic loss. There is no slip between the droplets and the surrounding vapor. Comparisons with other experimental quantities are also presented as needed to ensure that the non-equilibrium wet steam physics is accurately captured. Although the non-equilibrium models used cannot capture all the loss components present in actual flows, our efficiency predictions are much closer to experimental data than those of equilibrium simulations or the Baumann rule.

scholarly journals Prediction of Airfoil Stall Based on a Modified k−v2¯−ω Turbulence Model

Mathematics ◽  
2022 ◽  
Vol 10 (2) ◽  
pp. 272
Author(s):  
Chenyu Wu ◽  
Haoran Li ◽  
Yufei Zhang ◽  
Haixin Chen
Keyword(s):  
Experimental Data ◽  
Shear Layer ◽  
Turbulence Model ◽  
Turbulence Models ◽  
Reynolds Numbers ◽  
Navier Stokes ◽  
Trailing Edge ◽  
Naca0012 Airfoil ◽  
Separated Shear Layer ◽  
Non Equilibrium

The accuracy of an airfoil stall prediction heavily depends on the computation of the separated shear layer. Capturing the strong non-equilibrium turbulence in the shear layer is crucial for the accuracy of a stall prediction. In this paper, different Reynolds-averaged Navier–Stokes turbulence models are adopted and compared for airfoil stall prediction. The results show that the separated shear layer fixed k−v2¯−ω (abbreviated as SPF k−v2¯−ω) turbulence model captures the non-equilibrium turbulence in the separated shear layer well and gives satisfactory predictions of both thin-airfoil stall and trailing-edge stall. At small Reynolds numbers (Re~105), the relative error between the predicted CL,max of NACA64A010 by the SPF k−v2¯−ω model and the experimental data is less than 3.5%. At high Reynolds numbers (Re~106), the CL,max of NACA64A010 and NACA64A006 predicted by the SPF k−v2¯−ω model also has an error of less than 5.5% relative to the experimental data. The stall of the NACA0012 airfoil, which features trailing-edge stall, is also computed by the SPF k−v2¯−ω model. The SPF k−v2¯−ω model is also applied to a NACA0012 airfoil, which features trailing-edge stall and an error of CL relative to the experiment at CL>1.0 is smaller than 3.5%. The SPF k−v2¯−ω model shows higher accuracy than other turbulence models.

Molecular Dynamics Calculations of InSb Thermal Conductivity

2010 ◽  
Vol 297-301 ◽  
pp. 1400-1407
Author(s):  
Giovano de Oliveira Cardozo ◽  
José Pedro Rino
Keyword(s):  
Experimental Data ◽  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Infinite System ◽  
Thermal Conductivity Coefficient ◽  
Direct Method ◽  
Molecular Dynamics Calculations ◽  
Non Equilibrium Molecular Dynamics ◽  
Three Body ◽  
Non Equilibrium

Equilibrium and non-equilibrium molecular dynamics calculations of thermal conductivity coefficient are presented for bulk systems of InSb, using an effective two- and three-body inter atomic potential which demonstrated to be very transferable. In the calculations, the obtained coefficients were comparable to the experimental data. In the case of equilibrium simulations a Green-Kubo approach was used and the thermal conductivity was calculated for five temperatures between 300 K and 900 K. For the non equilibrium, or direct method, which is based on the Fourier’s law, the thermal conductivity coefficient was determined at a mean temperature of 300K. In this case it was used a pair of reservoirs, placed at a distance L from each other, and with internal temperatures fixed in 250 K, for the cold reservoir, and 350 K for the hot one. In order to obtain an approach to an infinite system coefficient, four different values of L were used, and the data was extrapolated to L→∞.

PARTON EVOLUTION FOR CHEMICAL EQUILIBRATION AT RHIC: DEPENDENCE ON INITIAL CONDITIONS

2007 ◽  
Vol 16 (07n08) ◽  
pp. 1993-1999
Author(s):  
LUAN CHENG ◽  
ENKE WANG
Keyword(s):  
Experimental Data ◽  
Energy Production ◽  
Transverse Energy ◽  
Initial Temperature ◽  
Initial Conditions ◽  
Numerical Results ◽  
Rate Equations ◽  
Important Ingredient ◽  
Chemical Equilibration ◽  
Non Equilibrium

An important ingredient for studying non-equilibrium evolution of partons at RHIC and LHC is to have physical initial conditions for the partonic system. In this paper we investigate the initial conditions with chemical non-equilibrium at RHIC. Considering the parton production, we studied evolution of the partonic medium with chemical non-equilibrium toward a fully equilibrated partonic system. By using a set of rate equations which describe the chemical equilibration of gluons and quarks, and putting different initial conditions, we obtained the transverse energy production dET/dy and particle multiplicities dN/dy. Comparing the experimental data of dET/dy and dN/dy with numerical results, we get following initial conditions for the formation of partonic system: the initial temperature is around 550 MeV and the initial fugacity λg is from 0.4 to 0.75. It is shown that, until the partonic medium freezes out the partonic system hasn't been totally chemical equilibrated.

Microstructure Evolution in Undercooled Ni-Si Melt

2013 ◽  
Vol 749 ◽  
pp. 349-355
Author(s):  
Kai Fan ◽  
Feng Liu ◽  
Bao Quan Fu ◽  
Wen Zhong Luo ◽  
Yao He Zhou
Keyword(s):  
Experimental Data ◽  
Grain Size ◽  
Grain Refinement ◽  
Microstructure Evolution ◽  
Solid Solubility ◽  
Molten Glass ◽  
Dendrite Fragmentation ◽  
Equilibrium Solidification ◽  
Good Agreement ◽  
Non Equilibrium

Upon non-equilibrium solidification, the intrinsic parameters, such as moving velocity, temperature, solute partition coefficient, and liquid and solid concentrations at the interface, deviate from their equilibrium characteristics, and the morphology of the as-solidified structure and the grain size are influenced by the non-equilibrium liqulid/solid transformation, which further influences the subquent solidstate transformation. Adopting molten glass purification technology combined with cycle superheating method, the microstructure evolution of Ni-11at.%Si alloy in different undercooling was investigated. It was found that, with the increase of the initial undercooling, grain refinement occurred in microstructures of undercooled Ni-11at.%Si alloy. Meanwhile, the NL model was used to discuss the two different dendrite morphologies. According to Karmas model for dendrite fragmentation, the grain refinement of undercooled Ni-11at.%Si alloy was in good agreement with the experimental data, and the grain size was reduced with the increasing ΔT. The energy-dispersive spectroscopy (EDS) measurement was applied to analyze the solid solubility of Si atom in α-Ni matrix. It was found that the solid solubility of Si atom in α-Ni matrix increased with undercooling. At the undercooling of T>220K , a complete solute trapping occurred.

scholarly journals Quantitative analysis of non-equilibrium systems from short-time experimental data

2021 ◽  
Author(s):  
Sreekanth K Manikandan ◽  
Subhrokoli Ghosh ◽  
Avijit Kundu ◽  
Biswajit Das ◽  
Vipin Agrawal ◽  
...  
Keyword(s):  
Experimental Data ◽  
Steady State ◽  
Quantitative Analysis ◽  
Large Class ◽  
Colloidal Particle ◽  
Particle System ◽  
Thermodynamic Force ◽  
Trajectory Data ◽  
Short Time ◽  
Non Equilibrium

Abstract We provide a minimal strategy for the quantitative analysis of a large class of non-equilibrium systems in a steady state using the short-time Thermodynamic Uncertainty Relation (TUR). From short-time trajectory data obtained from experiments, we demonstrate how we can simultaneously infer quantitatively, both the thermodynamic force field acting on the system, as well as the exact rate of entropy production. We benchmark this scheme first for an experimental study of a colloidal particle system where exact analytical results are known, before applying it to the case of a colloidal particle in a hydrodynamical flow field, where neither analytical nor numerical results are available. Our scheme hence provides a means, potentially exact for a large class of systems, to get a quantitative estimate of the entropy produced in maintaining a non-equilibrium system in a steady state, directly from experimental data.

NON-EQUILIBRIUM POROELECTROELASTIC THEORY OF POLYMER ELECTROLYTE WITHIN THE CONDITIONS OF WATER ELECTROLYSIS

2018 ◽  
pp. 87-112
Author(s):  
A. A. Kalinnikov ◽  
S. A. Grigoriev ◽  
D. G. Bessarabov
Keyword(s):  
Experimental Data ◽  
Mass Transfer ◽  
Polymer Electrolyte ◽  
Water Sorption ◽  
Water Electrolysis ◽  
Equilibrium Conditions ◽  
Transfer Processes ◽  
Mass Transfer Processes ◽  
Elastic Forces ◽  
Non Equilibrium

The paper considers a non-equilibrium poroelectroelastic theory of a polymer electrolyte under the conditions of water electrolysis with the purpose of further use for a theoretical description of mass transfer processes in l ayers of a membrane-electrode assembly. Moreover, this paper carries out the review and analysis of the models of electro- chemical and mass-exchange processes in the electrolyzers, and analyzes the problems of their physicochemical description. We make a conclusion about the need to use models of water sorption and scaling of polymer electrolyte and analyze the models of water sorption and swelling of the polymer electrolyte. It is concluded that the existing poroelectroelastic theory is the most suitable for its modification for use in non-equilibrium conditions during elec- trolysis. The basic equation of the balance of pressures of the classical equilibrium poroelectroelastic theory for polymer electrolyte is considered. A modification of the poroelectroelastic theory has been carried out in order to its use in non-equilibrium conditions of water electrolysis for the purpose of further modeling of mass transfer processes. Based on experimental data available in open sources, the paper makes an analysis of the properties and features of elastic forces in the polymer electrolyte, and then refines the dependencies of the elastic forces in the polymer electro- lyte from the swelling and temperature. Taking into account the existing experimental data on the permeability of gases in a polymer electrolyte and the feature of swelling of the polymer electrolyte in a contact with liquid water, parameters of the non-equilibrium poroelectroelastic theory have been obtained for the water electrolysis conditions.

Sign in / Sign up

Export Citation Format

Share Document