Numerical modeling of the aerodynamics, heat exchange, and combustion of a polydisperse ensemble of coke-ash particles in ascending axisymmetric two-phase flow

2009 ◽  
Vol 82 (4) ◽  
pp. 765-778
Author(s):  
B. B. Rokhman
2016 ◽  
Vol 110 ◽  
pp. 01070
Author(s):  
Alexander Shvab ◽  
Pavel Zyatikov ◽  
Marina Goyko

2017 ◽  
Vol 27 (12) ◽  
pp. 2799-2815
Author(s):  
Ewa Kolczyk ◽  
Zdzisław Miczkowski ◽  
Józef Czernecki

Purpose The purpose of this study is application of a numerical simulation for determination of the influence of geometric parameters of a furnace and hydrodynamics of the gas introduced by a vertical submerged lance on the process of feed mixing and temperature distribution. Design/methodology/approach A numerical simulation with Phoenics software was applied for modeling of liquid phase movement and heat exchange between the gas supplied through a lance and the slag feed in a top submerged lance (TSL) furnace. The simulation of a two-phase flow of a slag–gas mixture based on the inter phase slip algorithm module was conducted. The influence of selected parameters, such as depth of lance submergence, gas flow rate and change of furnace geometry, on the phenomena of movement was studied. Findings Growth of dynamics of mixing with the depth of lance submergence and with increase of gas velocity in the lance was observed. Formation of a recirculation zone in the liquid slag was registered. Movement of the slag caused by the gas flow brought homogenization of the temperature field. Originality/value The study applied the simulation of a two-phase flow in the liquid slag–gas system in steady state, taking into account heat transfer between phases. It provides possibilities for optimization and selection of process parameters within the scope of the developed new technology using a TSL furnace.


2012 ◽  
Vol 326-328 ◽  
pp. 221-226
Author(s):  
Jozef Kačur ◽  
Benny Malengier ◽  
Pavol Kišon

Numerical modeling of two-phase flow under centrifugation is presented in 1D.A new method is analysed to determine capillary-pressure curves. This method is based onmodeling the interface between the zone containing only wetting liquid and the zone containingwetting and non wetting liquids. This interface appears when into a fully saturated sample withwetting liquid we inject a non-wetting liquid. By means of this interface an efficient and correctnumerical approximation is created based upon the solution of ODE and DAE systems. Bothliquids are assumed to be immiscible and incompressible. This method is a good candidate tobe used in solution of inverse problem. Some numerical experiments are presented.


1979 ◽  
Vol 46 (6) ◽  
pp. 485-486
Author(s):  
P. A. Ushakov ◽  
A. A. Ivashkevich

Author(s):  
M.G. Surianinov ◽  
◽  
S. Jgalli ◽  
Al Echcheikh El Alaoui Douaa ◽  
◽  
...  

Abstract. The paper discusses the choice of a method for studying the distribution of snow loads on a biconcave roof of a hyperbolic paraboloid and its theoretical justification. It is noted that the numerical modeling of the aerodynamic characteristics of buildings and structures is a difficult and resource-intensive task due to the design features of building objects, which, as a rule, have a complex geometric shape, as well as due to a complex unsteady flow resulting from their flow around them. In addition, the task becomes more complicated due to the interference of vortex structures between different objects. Overcoming these objective difficulties became possible with the advent of modern specialized software systems, primarily ANSYS Fluent. Opportunities have appeared for accurate modeling with verification of the results obtained, which implies the use of an effective, well-tested mathematical apparatus. To implement the theory of two-phase flow, two methods based on numerical modeling are mainly used: the Euler-Lagrange method and the Euler-Euler method. The second method is used in the work. Comparative analysis, which investigates two-phase flow around different structures using different turbulence models (including RSM model, SST k-ω model, k-ε model and k-kl-ω model), shows that the k-kl-ω model is the best fit with experiment. ANSYS Fluent supports four multiphase models, i.e. VOF model, Mixture model, Wet Steam and Euler model. Compared to the other three models, the Mixture model provides better stability and lower computational costs, while the Euler model provides better accuracy, but at a higher computational cost . With a rather complex geometry and flow conditions, the use of the RANS approach does not lead to reliable simulation results. Moreover, unsteady turbulent flows cannot be reproduced. In real situations, landslides, saltations, and the suspended state of snow particles are closely related to the real effects of microbursts and bursts present at the surface of the boundary layer. Therefore, in further research, it is advisable to apply alternative approaches to RANS, which include Direct Numerical Simulation (DNS), Large Eddy Simulation (LES), and the hybrid RANS-LES approach to turbulence modeling, which combine efficiency LES techniques in tear-off free zones and the cost-effectiveness of RANS in near-wall areas.


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