Numerical modeling of contact-free control over crystal growth heat–mass transfer processes through heat field rotation

2001 ◽  
Vol 230 (1-2) ◽  
pp. 155-163 ◽  
Author(s):  
A.E. Kokh ◽  
V.N. Popov ◽  
P.W. Mokrushnikov
1987 ◽  
Vol 84 (3) ◽  
pp. 509-514 ◽  
Author(s):  
V.I. Bredikhin ◽  
V.P. Ershov ◽  
V.V. Korolikhin ◽  
V.N. Lizyakina ◽  
S.Yu Potapenko ◽  
...  

2006 ◽  
Vol 289 (2) ◽  
pp. 652-658 ◽  
Author(s):  
V.N. Popov ◽  
Yu.S. Tsivinskaya ◽  
T.B. Bekker ◽  
K.A. Kokh ◽  
A.E. Kokh

Author(s):  
N. A. Verezub ◽  
V. L. Manomenova ◽  
A. I. Prostomolotov

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.


2020 ◽  
Vol 23 (2) ◽  
pp. 77-86
Author(s):  
S. TIMOSHENKO ◽  
◽  
E. NIEMTSEV ◽  

Research is aimed at reducing the energy loss of foundry class arc furnace, which belongs to energy-consuming units with a non-rhythmic work schedule, and characterizes by low energy efficiency. Method of numerical modeling substantiates the concept of furnace modernization, which consists in rising the specific electric power by lowering the capacity at constant productivity, relative increasing of the liquid bath depth, reducing accumulation heat loss by refractory lining through introduction of energy saving water-cooled elements with a spatial structure in its local areas and intensification of heat and mass transfer processes in the "deep" bath with pneumatic stirring. It is determined that for arc furnaces with capacity of 12 and 6 tons, working in one shift, it is rational to reduce the capacity to 6 and 3 tons respectively and the bath shape factor (ratio of diameter to depth) from 5 to 2.5; installation of water-cooled elements in central endurance critical part of the roof and upper parts of the walls with coverage of 0.20-0.32 and 0.5-0.8 of working surface, respectively. With regard to the economy of heating systems, the expansion of the cooling system for the economic efficiency of modernization is 12 tons of chipboard with magnesite lining, so in the small world, dinas lining. For 6 t furnaces of water-cooling elements at the same time the magnesite lining is also effective, the protector is more cheap acidic lining (dinas), however, the water-cooling elements require a larger analogue. With available supply transformer, the specific power increases to 1 MVA/t, which will allow, due to intensification of heat and mass transfer processes, provide quantitative and qualitative indicators of production with lower, compared to the basic unit, heat loss. The implementation of proposed solutions will reduce energy consumption by 75 kWh/t and, taking into account the cost of refractory, provide an economic effect of 320-515 UAH/t.


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