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SELECTION OF THE OPTIMAL DESIGN OF GAS DISTRIBUTION DEVICE FOR THE VORTEX GRANULATOR

SELECTION OF THE OPTIMAL DESIGN OF GAS DISTRIBUTION DEVICE FOR THE VORTEX GRANULATORSELECTION OF THE OPTIMAL DESIGN OF GAS DISTRIBUTION DEVICE FOR THE VORTEX GRANULATOR
Omelyanenko Vitaliy, candidate of economics

Artyukhov Artem, associate professor, candidate of technical science

Sumy State University, Ukraine

Championship participant: the National Research Analytics Championship - "Ukraine";

the Open European-Asian Research Analytics Championship;

The article deals with investigation of trajectory of granules motion in vortex granulator with various types of gas distribution devices. The results of investigations of features of granules motion in a vortex granulator are presented. Epures of circular speed of gas stream for each type of gas distribution device are presented. Operating range for different types of gas distribution devices according to volume content of disperse phase in two-phase system is identified. The findings are the basis for a technique of vortex granulator engineering calculation.

Keywords: vortex granulator, gas distribution device, dispersed phase, engineering calculation.

Статья посвящена исследованию траектории движения гранул в вихревом грануляторе с различными типами газораспределительных устройств. Приведены результаты исследований особенности движения гранул в вихревом грануляторе. Представлены эпюры окружной скорости газового потока для каждого типа газораспределительного устройства. Установлен диапазон работы различных типов газораспределительных устройств в зависимости от объемного содержания дисперсной фазы в двухфазной системе. Полученные данные являются основой для создания методики инженерного расчёта вихревых грануляторов.

Ключевые слова: вихревой гранулятор, газораспределительное устройство, дисперсная фаза, инженерный расчёт.

 

Rotating (twisted) traffic flows in vortex devices is provided through guide elements, which may have different constructive design [1]. Twisting units are used in modern heat– and mass transfer devices, allowing to provide gas flow with angular speed component and form partial twist.

Gas flow twisting o can be accomplished by following constructive solutions [2].

  • – Impact on gas flow in place of gas flow entrance to the system (blade twisting units, simultaneous application of several twisting devices, tangential entry of gas stream through one or more nozzles);
  • – Effects on gas flow along the length of devices’ working space (tape and screw eddy, tangential introduction of gas flow in several places in the height of device);

Simultaneous gas-dispersion flow twist may be done by rotating mechanical devices, such as circuit Wurster, honeykomb or turntables with blades.

Researchers have accumulated extensive experimental data on heat transfer in pipes with different types of plug intensifiers, that is covering a wide range of loads and physical properties of environment [3], of vortex flows hydrodynamics in channels with screw twist units and in the form of twisted ribbons, that completely cover the section of channels [4; 5]. Data from the two-phase heat and mass transfer in swirling flows in relation to granulation processes are virtually absent.

In the study the authors present the research results of impact of gas-distributing device construction on the granules movement mode.

The experiment was conducted at the initial gas flow spin speed at 10 m / s. During experimental studies, along with visual observation estimation of gas flow angular speed measurement were done, which has a major impact on vortex weighted layer structure, its uniformity and stability.

Gas distribution plane type device, with holes and combined design.

The analysis of granule`s trajectory (average content of dispersed phase in two-phase system ψ = 0,15) and epures of gas flow speed components for each gas distribution units (Fig. 1), which are considered, give to authors possibilities of determination the characteristics of their operation and recommend each units type for certain conditions of application.

    

Fig. 1. Granules movement trajectory and epures of angular speed component the gas stream for gas distribution unit with inclined holes

 

It should be noted, that with increasing of average content of dispersed phase in  two-phase system stability layer vortex weighted distribution for all types of devices becomes broken, but the range for stable operation of devices is different.

 

       

Fig. 2. Granules movement trajectory and diagrams of angular speed component of gas stream for gas distribution unit with the central vertical and peripheral inclined holes

      

Fig. 3. Granules movement trajectory and diagrams of angular speed component of gas stream for gas distribution unit with the central inclined and peripheral vertical inclined holes

      

Fig. 4. Granules movement trajectory and diagrams of angular speed component of gas stream for gas distribution unit with the central inclined and peripheral vertical inclined holes

 

Gas distribution units with holes and combined type are recommended for use of devices with low power value ψ up to 0.2. A more average content of dispersed phase the structure of stable vortex weighted layer is broken, spontaneous ripple zones granules appear. The feature of weighted layer, that is created using in devices using gas distribution units of such type, is intense lateral granules mixing in so-called «active» granulator`s zone immediately above the gas distribution unit. When using in central part gas distribution unit vertical holes we can observe vertical circulation granules with small intensity. Such gas distribution device combines the advantages of vortex weighted layer with the possibility of saving materials strength with small value.

       

Fig. 5. Granules movement trajectory and epures of angular speed component of gas stream for gas distribution unit of combined type

Gas distribution unit of slot type as it is shown in Fig. , differs by stable vortex structures at twice lower load for dispersed phase. Such gas distribution unit can be recommended as the best because of broad range of loads on dispersed phase (ψ = 0,1-0,3) while maintaining stable vortex granules flow.

Fig. 6. Granules trajectory in gas-distributing unit of slot type application: a – ψ = 0,08; b – ψ = 0,15; c – ψ = 0,21; d – ψ = 0,31; e – ψ = 0,43; f – ψ = 0,6

 

Considered construction of gas distribution devices are working well for low power devices with ψ up to 0.3. For larger capacity and greater relative content of dispersed phase it is necessary to use other types of gas distribution devices.

Gas distribution device with blades.

When specifying for calculating the speed components distribution in the input section we have examined given epures variants appropriate to installation blades angle of vortex granulator twisting unit 60, 30 and 15 degrees from the vertical axis of device. The research results are presented in Fig 7.

Fig. 7. The distribution of granules in device when inclination angle of blades of eddy in Q = 0,63 m3 / s and the number of blades of gas-distributing device n = 8 (visual appearance and speed distribution in height of granulator): a – 60 °; b – 30 °; c – 15 °:

  • 1 – granules flow;
  • 2 – twisting  unit with finished product unloading;
  • 3 – blades of twisting  unit;
  • 4 – inner cone;
  • 5 – tapered annular space for internal seeding agent circulation.

Heat transfer agent speed components epures analysis allows to suggest, that if the blades of twisting unit installation angle is 60° we can observe uneven distribution of speeds along the radius at different for height sections granulator. This will to granules pressing to the walls of device, to complication of granules classification and separation processes through their movement in dense layer along the wall and, consequently, their uneven distribution by granulator`s volume. In the course of experiment we also observed, that move dense granule layer rotating in narrow near-wall zone, due to significant size of granules centrifugal force and the relatively small value of the environment resistance. Virtually there is no internal recirculation of quite small granules through dense traffic and collide them with the larger granules, that reduce part of acquired axial speed.

The characteristics of heat transfer agent speed components distribution while reducing the angle of twisting unit blades to 300 allows to tend alignment along the radius, giving rise pressing to smaller particles to the walls machine and the separation of some of them from the walls. This will create more favorable conditions for classification and separation processes conditions, than in the previous case, which ultimately will lead to more even granules distribution in granulator volume and small granules recirculation starting.

Also during the experiment we have found, that granules are moving by spiral trajectory in rarefied circular near wall layer. The volume of domestic central cone is not filled with granules. Small granules fracture begins removed from the internal cone volume and due to centrifugal acceleration and the fall of axial speed component heat transfer agent flow above the upper base of the inner cone, falls into the annular tapered space for internal circulation of seeding agent. Granules with size close to size of commodity fraction do not leave the inner cone volume, whereby the conditions for granules growing to necessary granulometric structure. Thus, the practical results, obtained within  the experiment, meet the findings, which were obtained from the theoretical results analysis.

View of heat transfer agent flows speed components epures at blades installation angle equal 150 allows to observe, that we obtain more even distribution of angular speed component along the radius, than in previous two cases, which allows to suggest about more even distribution of granules in granulator’s volume.

After an experiment with the blades angle installation of twisting unit in 150 we obtained results, that confirming above mentioned assumptions. From experimental data it should be noted good granules filling of internal cone volume, steady process of classification and separation processes, stable circulation of small fractions granules through an annular conical space.

The degree of heat transfer agent flow twist is characterized has significant impact on granules flow hydrodynamics in vortex granulator. For obtaining even distribution of granules in vortex granulator volume it is necessary to strive for not very large values of angular speeds, by that the degree of coolant flow twist is determined, and to try for maximum possible aligning of coolant flow speeds components allocation in granulator`s section.

Because of intensive granules movement with stable spiral similar trajectory we accept such gas distribution unit design as an optimal for devices of average power with volume concentration of dispersed phase in two-phase flow up to 0.4. It should be noted, that in the case of vortex layer for devices with large capacity (by increasing the height of granules layer) there is the problem of horizontal granules circulation from the central area to the periphery of device. For solving this problem we can use units with combined weighted layer – spouting layer in device`s center and vortex layer in device`s periphery.

As a result research we have identified the influence of gas-distributing device design and configuration of granulator`s working volume on stability of vortex weighted layer according to the volume content of dispersed phase in two-phase system, the proposed ranges of use of each type of distribution devices presented granulator work mode the combined weighted layer.

 

This work was carried out under the project «Improving the efficiency of granulators and dryers with active hydrodynamic regimes for obtaining, modification and encapsulation of fertilizers», state registration No. 0116U006812.

 

References:

  • 1. Суслов А.Д., Иванов С.В., Мурашкин А.В., Чижиков Ю.В. Вихревые аппараты. – М.: Машиностроение, 1985. – 256 с.
  • 2. Khalatov A. A. Heat transfer in swirled flows / Journal of Engineering Physics and Thermophysics. – 1993. – vol. 64, No. 6. – pp. 546-553.
  • 3. Гупта Л., Лилли Д, Сайред Н. Закрученные потоки / Пер. с англ. – М.: Мир, 1987. – 588 с.
  • 4. Митрофанова О.В. Гидродинамика и теплообмен закрученных потоков в каналах ядерно-энергетических установок. – М.: Физматлит, 2010. – 288 с.
  • 5. Теплообмен и гидродинамика закрученных и вихревых потоков в каналах / Т. В. Доник, Д. Н. Письменный; под ред.: А. А. Халатов ; НАН Украины, Ин-т технической теплофизики. – Киев : Наукова думка, 2014 . – 189 с.
  • 6. Artyukhov A.E., Omelyanenko V.A., Sklabinsky V.I. Application of integrated marketing in development and technology transfer in universities (case of chemical industry) // GISAP: Economics, Jurisprudence and Management. – 2016. – № 9. – pp.  11–15.
  • 7. Artyukhov A.E., Omelyanenko V.A., Artyukhov N.O. Strategіc framework and methodіcal bases of technologіcal package development management // Marketing and Management of Innovations. – 2016. – № 3. – С. 170–179.

 

 

 

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Comments: 3

Treschalin Michail Yuriyevich

Уважаемые коллеги! Вы провели оптимизацию экспериментальным путем. Полученные данные могут быть основой для мат моделирования процессов и, может быть, оптимизации конструкции устройства. Думаю, в такой постановке, задача много интереснее. С уважением М.Ю. Трещалин

Vladimir Karlov

В работе представлены результаты исследования движения гранул в вихревом грануляторе с различными типами газораспределительных устройств. Разработаны оригинальные методы и средства проведения экспериментальных исследований с последующей их обработкой. На основе полученных экспериментальных результатов можно пожелать авторам успешно создать эффективные методики для инженерных расчетов вихревых грануляторов. С уважением В.А. Карлов.

Simonian Geworg

Уважаемые коллеги хорошая экспериментальная работа. Ваша статья посвящена исследованию траектории движения гранул в вихревом грануляторе, что позволит создать методику для расчета вихревых гранулятов. С уважением к.х.н. Г.С.Симонян
Comments: 3

Treschalin Michail Yuriyevich

Уважаемые коллеги! Вы провели оптимизацию экспериментальным путем. Полученные данные могут быть основой для мат моделирования процессов и, может быть, оптимизации конструкции устройства. Думаю, в такой постановке, задача много интереснее. С уважением М.Ю. Трещалин

Vladimir Karlov

В работе представлены результаты исследования движения гранул в вихревом грануляторе с различными типами газораспределительных устройств. Разработаны оригинальные методы и средства проведения экспериментальных исследований с последующей их обработкой. На основе полученных экспериментальных результатов можно пожелать авторам успешно создать эффективные методики для инженерных расчетов вихревых грануляторов. С уважением В.А. Карлов.

Simonian Geworg

Уважаемые коллеги хорошая экспериментальная работа. Ваша статья посвящена исследованию траектории движения гранул в вихревом грануляторе, что позволит создать методику для расчета вихревых гранулятов. С уважением к.х.н. Г.С.Симонян
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