Hydrodynamics and Mass Transfer during the Solution Growth of the K2(Co,Ni)(SO4)2•6H2O Mixed Crystals in the Shapers

Mathematical models of the hydrodynamics and mass transfer processes during the mixed crystal growth from low-temperature aqueous solutions have been analyzed. The features of these processes are caused by complex design of the crystallizer with a shaper. Two models of the solution flowing into the shaper have been considered. In the first model, the solution is fed to the central part of the crystal. The second model presents a peripheral solution supply along the shaper perimeter, which allows us to create a swirling flow. The calculation models correspond to laminar and turbulent regimes of solution flow during the growth of K2(Co,Ni)(SO4)2•6H2O mixed crystal from an aqueous solution.

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Modeling the mass transfer processes in the growth of KDP crystals from solution

Izvestiya Vysshikh Uchebnykh Zavedenii Materialy Elektronnoi Tekhniki = Materials of Electronics Engineering ◽

10.17073/1609-3577-2018-1-26-34 ◽

2019 ◽

Vol 21 (1) ◽

pp. 26-34

Author(s):

N. A. Verezub ◽

V. L. Manomenova ◽

A. I. Prostomolotov

Keyword(s):

Mathematical Model ◽

Aqueous Solution ◽

Mass Transfer ◽

Crystal Growth ◽

Potassium Dihydrogen Phosphate ◽

Dihydrogen Phosphate ◽

Potassium Dihydrogen ◽

Transfer Processes ◽

Mass Transfer Processes ◽

Kdp Crystals

Finding the conditions of high-speed single crystal growth with an appropriate quality is a priority for the industrial production of crystalline materials. Crystals of potassium dihydrogen phosphate (KDP) are important optical materials, they are grown from an aqueous solution and an increase in the rate of growth and quality of a single crystal is of great practical importance.In this paper, mathematical simulation of hydrodynamic and mass transfer processes in growing KDP crystals is performed. The flow and mass transfer are modeled within the framework of continuous medium, which is considered as an aqueous solution of a special salt — potassium dihydrogen phosphate. This salt dissolves in water to a saturation level at a high temperature. Then, such supersaturated solution is used to grow crystals at lower temperatures in non-flowing and flowing crystallizers. The mathematical model is considered in a conjugate formulation with allowance for mass transfer in the«solution—crystal» system. Local features of hydrodynamics and mass transfer in a solution near the surface of a growing crystal are determined, which can affect on the local (for a particular place and direction) crystal growth rate and the formation of defects. The requirements to the crystallizers that provide the «necessary» hydrodynamics in the solution are discussed. Its validation is shown for the flow around a long horizontal plate simulating the growing facet of the crystal. The rate of precipitation of salt was evaluated by the proposed mathematical model, which matches the calculation of solution flow according to the Navier-Stokes equations for an incompressible fluid with a thermodynamic condition for the normal growth of a face under conditions of two-dimensional nucleation. The action of the flowing crystallizers was analyzed for various solution inflows (axial and ring) and its outflow through the axial bottom hole.

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HYDRODYNAMICS AND MASS TRANSFER IN SPECIAL CRYSTALLIZER DESIGNS

Mathematical modeling in materials science of electronic component ◽

10.29003/m1524.mmmsec-2020/78-82 ◽

2020 ◽

Author(s):

Anatoliy Prostomolotov ◽

Natalia Verezub

Keyword(s):

Mass Transfer ◽

Crystal Growth ◽

Swirling Flow ◽

Salt Solutions ◽

Solution Flow ◽

Water Salt ◽

Laminar And Turbulent Regimes ◽

Calculation Models

Two variants of the crystallizer are considered: in the first, the solution is supplied to the central crystal part, in the second, there is a peripheral solution supply along the crystallizer perimeter, what provides creating its swirling flow. The calculation models corresponded to the laminar and turbulent regimes of the solution flow during the mixed KCNSH crystal growth from a mixture of two water-salt solutions (cobalt KCSH and nickel KNSH salts).

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