scholarly journals Model Kinetic Equations for Multiply Ionized Gas Mixtures

2021 ◽  
Vol 8 ◽  
Author(s):  
Maria A. Rydalevskaya ◽  
Yulia N. Voroshilova
Keyword(s):  
Equilibrium Distribution ◽  
Local Equilibrium ◽  
Kinetic Equations ◽  
Gas Mixtures ◽  
Distribution Functions ◽  
Transport Processes ◽  
Ionized Gas ◽  
Model Kinetic Equations ◽  
Ideal Gases ◽  
Model Equations

Model kinetic equations are proposed for the description of ionized monoatomic gas mixture flows. The mixtures are assumed enough rarefied to be treated as ideal gases after multiple ionization steps. The model equations contain the equilibrium distribution functions for the components of the gas mixtures under consideration like it was done in BGK equations and their well-known generalizations. However, in this paper the new forms of the equilibrium distribution functions are used which correspond to the entropy maximum under the constraints of momentum, total energy, nuclei and electrons (both bound and free) conservation. It is shown that the derived model equations allow us to study the local equilibrium flows of the ionized gases and the transport processes of energy, nuclei and electrons in the non-equilibrium conditions.

Development and Application of a Simulation Tool for Biomass Gasification Based Processes

2008 ◽  
Vol 6 (1) ◽  
Author(s):  
Tobias Pröll ◽  
Hermann Hofbauer
Keyword(s):  
Background Information ◽  
Simulation Tool ◽  
Water Steam ◽  
Organic Mixtures ◽  
Ideal Gases ◽  
Dual Fluidized Bed ◽  
Modelling Environment ◽  
Model Equations ◽  
Key Aspects ◽  
Energy Balances

A simulation tool for gasification based processes is presented for an equation-oriented, steady state modelling environment. The approach aims at an adequate description of phenomena linked to gasification. Background information is provided regarding the structure of the framework, thermodynamic data processing, and on the formulation of the model equations. The implemented substance streams are water/steam, ideal gases, inorganic solids, and organic mixtures. The models are based upon mass and energy balances and feature thermodynamic considerations. The addition of correlations for fluid dynamics or chemical kinetics is generally possible but not within the focus of this paper. The key-aspects of the typical unit-models, like pumps, turbines, heat exchangers, separators and chemical reactors are highlighted. The model of a dual-fluidized bed biomass gasifier is presented in detail. In a final case study, the suitability of the simulation tool is demonstrated for the description of the gasification-based biomass combined heat and power plant in Güssing/Austria.

Exploring probability distribution functions best-fitting the kinetic energy of coarse particles at above threshold flow conditions

2021 ◽  
Author(s):  
Hamed Farhadi ◽  
Manousos Valyrakis
Keyword(s):  
Probability Distribution ◽  
Kinetic Energy ◽  
Test Section ◽  
Particle Transport ◽  
River Flow ◽  
Distribution Functions ◽  
Transport Processes ◽  
Flow Conditions ◽  
Probability Distribution Functions ◽  
Transport Regime

<p>Applying an instrumented particle [1-3], the probability density functions of kinetic energy of a coarse particle (at different solid densities) mobilised over a range of above threshold flow conditions conditions corresponding to the intermittent transport regime, were explored. The experiments were conducted in the Water Engineering Lab at the University of Glasgow on a tilting recirculating flume with 800 (length) × 90 (width) cm dimension. Twelve different flow conditions corresponding to intermittent transport regime for the range of particle densities examined herein, have been implemented in this research. Ensuring fully developed flow conditions, the start of the test section was located at 3.2 meters upstream of the flume outlet. The bed surface of the flume is flat and made up of well-packed glass beads of 16.2 mm diameter, offering a uniform roughness over which the instrumented particle is transported. MEMS sensors are embedded within the instrumented particle with 3-axis gyroscope and 3-axis accelerometer. At the beginning of each experimental run, instrumented particle is placed at the upstream of the test section, fully exposed to the free stream flow. Its motion is recorded with top and side cameras to enable a deeper understanding of particle transport processes. Using results from sets of instrumented particle transport experiments with varying flow rates and particle densities, the probability distribution functions (PDFs) of the instrumented particles kinetic energy, were generated. The best-fitted PDFs were selected by applying the Kolmogorov-Smirnov test and the results were discussed considering the light of the recent literature of the particle velocity distributions.</p><p>[1] Valyrakis, M.; Alexakis, A. Development of a “smart-pebble” for tracking sediment transport. In Proceedings of the International Conference on Fluvial Hydraulics (River Flow 2016), St. Louis, MO, USA, 12–15 July 2016.</p><p>[2] Al-Obaidi, K., Xu, Y. & Valyrakis, M. 2020, The Design and Calibration of Instrumented Particles for Assessing Water Infrastructure Hazards, Journal of Sensors and Actuator Networks, vol. 9, no. 3, 36.</p><p>[3] Al-Obaidi, K. & Valyrakis, M. 2020, Asensory instrumented particle for environmental monitoring applications: development and calibration, IEEE sensors journal (accepted).</p>

scholarly journals Submesoscale Dynamics in the Northern Gulf of Mexico. Part II: Temperature–Salinity Relations and Cross-Shelf Transport Processes

2017 ◽  
Vol 47 (9) ◽  
pp. 2347-2360 ◽  
Author(s):  
Roy Barkan ◽  
James C. McWilliams ◽  
M. Jeroen Molemaker ◽  
Jun Choi ◽  
Kaushik Srinivasan ◽  
...  
Keyword(s):  
Potential Energy ◽  
Gulf Of Mexico ◽  
Horizontal Resolution ◽  
Relative Effect ◽  
Distribution Functions ◽  
Transport Processes ◽  
Effect Of Temperature ◽  
Loop Current ◽  
Northern Gulf Of Mexico ◽  
Available Potential Energy

AbstractThis paper, the second of three, investigates submesoscale dynamics in the northern Gulf of Mexico under the influence of the Mississippi–Atchafalaya River system, using numerical simulations at 500-m horizontal resolution with climatological atmospheric forcing. The Turner angle Tu, a measure of the relative effect of temperature and salinity on density, is examined with respect to submesoscale current generation in runs with and without riverine forcing. Surface Tu probability density functions in solutions including rivers show a temperature-dominated signal offshore, associated with Loop Current water, and a nearshore salinity-dominated signal, associated with fresh river water, without a clear compensating signal, as often found instead in the ocean’s mixed layer. The corresponding probability distribution functions in the absence of rivers differ, illustrating the key role played by the freshwater output in determining temperature–salinity distributions in the northern Gulf of Mexico during both winter and summer. A quantity referred to as temperature–salinity covariance is proposed to determine what fraction of the available potential energy that is released during the generation of submesoscale circulations leads to the destruction of density gradients while leaving spice gradients untouched, thereby leading to compensation. It is shown that the fresh river fronts to the east of the Bird’s Foot can evolve toward compensation in concert with a gradual release of available potential energy. It is further demonstrated that, during winter, the cross-shelf freshwater transport mechanism to the west of the Bird’s Foot is well approximated by a diffusive process, whereas to the east is better represented by a ballistic process associated with the Mississippi water that converges in a jetlike pattern.

scholarly journals Equilibrium Spin Distribution From Detailed Balance

2021 ◽  
Vol 81 (9) ◽  
Author(s):  
Ziyue Wang ◽  
Xingyu Guo ◽  
Pengfei Zhuang
Keyword(s):  
Spin Polarization ◽  
Transport Theory ◽  
Axial Vector ◽  
Detailed Balance ◽  
Kinetic Equations ◽  
Distribution Functions ◽  
Spin Distribution ◽  
Balance Principle ◽  
Quark Level ◽  
Vector Distribution

AbstractAs the core ingredient for spin polarization, the equilibrium spin distribution function that eliminates the collision terms is derived from the detailed balance principle. The kinetic theory for interacting fermionic systems is applied to the Nambu–Jona-Lasinio model at quark level. Under the semi-classical expansion with respect to $$\hbar $$ ħ , the kinetic equations for the vector and axial-vector distribution functions are obtained with collision terms. For an initially unpolarized system, spin polarization can be generated at the first order of $$\hbar $$ ħ from the coupling between the vector and axial-vector charges. Different from the classical transport theory, the collision terms in a quantum theory vanish only in global equilibrium with Killing condition.

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