scholarly journals Особенности микрокристаллизации 50 % двухкомпонентных металлических расплавов в модели переходной двухфазной зоны в диффузионно-релаксационном режиме

2019 ◽  
Vol 21 (2) ◽  
pp. 164-181
Author(s):  
Yury A. Baikov ◽  
Nikolai I. Petrov ◽  
Margorita I. Timoshina ◽  
Evgeniy V. Akimov
Keyword(s):  
Transition Region ◽  
Steady State Solution ◽  
Phase Zone ◽  
Two Phase ◽  
Mathematical Mode ◽  
Metal Melts ◽  
Two Component ◽  
Crystal Transition ◽  
Supercooled Melt ◽  
Metallic Melts

    В диффузионно-релаксационном режиме кристаллизации 50% двухкомпонентных металлических расплавов в модели переходной  двухфазной зоны оценены термодинамические параметры, при которых возможно образование полностью разупорядоченной  двухкомпонентной кристаллической фазы с простой кубической элементарной решеткой стехиометрического состава. Исследована область вблизи точки разупорядочения кристаллической фазы и установлен закон стремления параметра дальнего порядка к нулю при достижении критической температуры (переохлаждения) системы двухкомпонентный расплав-кристалл. Установлены кинетические особенности роста кристаллической фазы в точке разупорядочения. Установлен закон восстановления упорядоченной двухкомпонентной кристаллической фазы во времени. Оценены возможные значения времен релаксации при переходе из разупорядоченной двухкомпонентной кристаллической фазы с простой кубической элементарной ячейкой к полностью  упорядоченной. Установлены кинетические особенности образования полностью упорядоченного двухкомпонентного кристалла.       REFERENCES Sarkisov P. D., Baikov Yu. A., Meshalkin V. P. Matematicheskoe modelirovanie kristallizatsii odno- i dvukhkomponentnykh metallicheskikh rasplavov [The one- and binary metallic melts mathematical mode ling crystallization]. Moscow, Physmatlit Publ., 2003. 378 p. (in Russ.) Baikov Y. A., Petrov N. I. Structure of the Transitive Two-Phase Zone in Crystallization of Two-Component Metal Melts. Russian Physics Journal, 2014, v. 57(4), pp. 459–468. https://doi.org/10.1007/s11182-014-0262-2 Baikov Yu. A., Petrov N. I. Special Features of disordering in Crystallization of Two-Component Metal Melts in the Model of Two-Phase Transitive Zone. Russian Physics Journal, 2014, v. 57(5), pp. 598–614. https://doi.org/10.1007/s11182-014-0282-y Petrov N. I. The Crystal Disordering Study When Growing From the Binary Metallic Melts. National University of Science and Technology «MISiS» Dis. Cand. Phys.-Mat. Sci. Moscow, 2017, 180 p. URL: http:// misis.ru/fi les/6902/Petrov_AR.pdf (in Russ.) Sarkissov P. D., Baikov Yu. A., Meshalkin V. P. Order-disorder processes in crystals when crystallizing binary metallic melts. Doklady Physics, 2003, v. 48(6), pp. 290–295. https://doi.org/10.1134/1.1591316 Chistyakov Yu. D., Baikov Yu. A., Schneider H. G., Ruth V. The order-disorder transformation at supercooled melt/crystal transition region of binary melts (I) the master equation. Crystal Research and Technology, 1985, v. 20(8), pp. 1007–1014. https://doi.org/10.1002/crat.2170200802 Chistyakov Yu. D., Baikov Yu. A., Schneider H. G., Ruth V. The order-disorder transformation at supercooled melt/crystal transition region of binary melts (II) the steady state solution // Crystal Research and Technology, 1985, v. 20(9), pp. 1149–1156. https://doi.org/10.1002/crat.2170200903 Guinier A. J., Griffoul R. Compte Rendu, 1945, v. 221, pp. 121. Guinier A. J. Imperfections of crystal lattices as investigated by the study of X-ray diffuse scattering // Proceedings of the Physical Society, 1945, v. 57(4), pp. 310–324. https://doi.org/10.1088/0959-5309/57/4/306 Schneider H. G. Collection: Advances in Epitaxy and Endotaxy. Akademiai Kiado, Budapest, 1976, p. 23. Chistyakov Yu. D., Baikov Yu. A. Collection: Advances in Epitaxy and Endotaxy. Akademiai Kiado, Budapest, 1976, p. 159. Chistyakov Yu. D., Baikov Yu. A. Collection: Advances in Epitaxy and Endotaxy. Akademiai Kiado, Budapest, 1976, p. 257.

Gas-Water Flow Behaviour During Mutual Displacement in Porous Media

2017 ◽  
Vol 10 (1) ◽  
pp. 13-22
Author(s):  
Renyi Cao ◽  
Junjie Xu ◽  
Xiaoping Yang ◽  
Renkai Jiang ◽  
Changchao Chen
Keyword(s):  
Porous Media ◽  
Relative Permeability ◽  
Gas Storage ◽  
Fluid Distribution ◽  
Water Displacement ◽  
Phase Zone ◽  
Two Phase ◽  
Flow Process ◽  
Single Well ◽  
Mutual Displacement

During oilfield development, there exist multi-cycle gas–water mutual displacement processes. This means that a cycling process such as water driving gas–gas driving water–water driving gas is used for the operation of injection and production in a single well (such as foam huff and puff in single well or water-bearing gas storage). In this paper, by using core- and micro-pore scales model, we study the distribution of gas and water and the flow process of gas-water mutual displacement. We find that gas and water are easier to disperse in the porous media and do not flow in continuous gas and water phases. The Jamin effect of the gas or bubble becomes more severe and makes the flow mechanism of multi-cycle gas–water displacement different from the conventional water driving gas or gas driving water processes. Based on experiments of gas–water mutual displacement, the changing mechanism of gas–water displacement is determined. The results indicate that (1) after gas–water mutual displacement, the residual gas saturation of a gas–water coexistence zone becomes larger and the two-phase zone becomes narrower, (2) increasing the number of injection and production cycles causes the relative permeability of gas to increase and relative permeability for water to decrease, (3) it becomes easier for gas to intrude and the invaded water becomes more difficult to drive out and (4) the microcosmic fluid distribution of each stage have a great difference, which caused the two-phase region becomes narrower and effective volume of gas storage becomes narrower.

Heat Transfer in Porous Media Heated From Above With Evaporation, Condensation, and Capillary Effects

1983 ◽  
Vol 105 (3) ◽  
pp. 485-492 ◽  
Author(s):  
K. S. Udell
Keyword(s):  
Stable State ◽  
Superheated Liquid ◽  
Phase Zone ◽  
Two Phase ◽  
Water Steam ◽  
Zone Length ◽  
Compressed Liquid ◽  
Pressure Lowering ◽  
Darcy’S Equations ◽  
Convection Dominated

Heat and mass transfer characteristics of a sand-water-steam system heated at the top and cooled at the bottom were studied. It was found that at steady-state conditions the system segregated into three regions. The top region was conduction-dominated with the voids containing a stationary superheated steam. The middle region was convection-dominated, nearly isothermal, and exhibited an upward flow of the liquid by capillary forces and a downward flow of steam due to a slight pressure gradient. The bottom portion contained a stationary compressed liquid and was also conduction dominated. The length of the two-phase convection zone was evaluated through the application of Darcy’s equations for two-phase flow and correlations of relative permeabilities and capillary pressure data. The model was in excellent agreement with the observed results, predicting a decreasing two-phase zone length with increasing heat flux. The thermodynamics of the two-phase zone were also analyzed. It was found that the vapor phase was in a superheated state as described by the Kelvin equation for vapor pressure lowering. Also, it was evident that the liquid must also be superheated for thermodynamic equilibrium to result. A stability analysis demonstrated that the superheated liquid can exist in an unconditionally stable state under conditions typical of porous systems. The degree of liquid superheat within the two-phase zone of these experiments was obtained.

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