JUSTIFICATION OF THE MUTUAL ARRANGEMENT OF THE BLADES WITH A DEVICE THAT CREATES AN ADDITIONAL AIR FLOW IN THE DESIGN OF A CENTRIFUGAL APPARATUS

ABSTRACT

The object of research is the process of increasing the initial rate of flat application of mineral fertilizers by throwing them from the pneumomechanical apparatus.

Because the aerodynamic properties of mineral fertilizer grains vary, after they are discharged from the centrifugal apparatus, a process of fractionation is observed according to the properties of the sails during free movement in the air. This process cannot be reversed with an existing decentralized disk apparatus. As a result, the possibility of improving the quality of mineral fertilizers on the field surface is limited.

A new type of pneumomechanical apparatus scheme was developed, developed and field tests were carried out using a method of critical study of the technological processes of centrifugal apparatus in existing and patent information materials and the combination of structural elements in a single working part and the rules of classical mechanics. A mathematical expression was derived and calculated that took into account the formation of additional airflow and the change in the relative velocity of the fertilizer grains relative to it under its influence.

The centrifugal pneumomechanical device is designed to increase the initial speed by simultaneously performing two functions, the first - the throwing of mineral fertilizers, the second - creating an additional air flow and directing it behind the  thrown  fertilizer grains.

The proposed centrifugal pneumomechanical apparatus ensures that component fertilizers of different sizes, shapes and densities are spread evenly over the field surface.

АННОТАЦИЯ

Объектом исследования является процесс повышения начальной нормы плоского внесения минеральных удобрений путем выброса их из пневмомеханического аппарата.

Поскольку аэродинамические свойства зерен минеральных удобрений различны, после их выгрузки из центробежного аппарата наблюдается процесс фракционирования по свойствам парусов при свободном движении в воздухе. Этот процесс нельзя обратить вспять с помощью существующего децентрализованного дискового устройства. В результате возможности улучшения качества минеральных удобрений на поверхности поля ограничены.

Разработана схема пневмомеханического аппарата нового типа, разработаны и проведены полигонные испытания методом критического изучения технологических процессов центробежного аппарата в существующих и патентных информационных материалах и совмещением конструктивных элементов в единой рабочей части и нормами классической механики. Получено и рассчитано математическое выражение, учитывающее образование дополнительного воздушного потока и изменение относительной скорости движения зерен удобрения относительно него под его воздействием.

Центробежное пневмомеханическое устройство предназначено для увеличения начальной скорости за счет одновременного выполнения двух функций, первая - разбрасывание минеральных удобрений, вторая - создание дополнительного воздушного потока и направление его за выбрасываемыми зернами удобрения.

Предлагаемый центробежный пневмомеханический аппарат обеспечивает равномерное распределение по поверхности поля составных удобрений разной крупности, формы и плотности.

Keywords: mineral fertilizers, centrifugal pneumomechanical apparatus, additional air flow, initial velocity, fertilizer application.

Ключевые слова: минеральные удобрения, центробежный пневмомеханический аппарат, дополнительный поток воздуха, начальная скорость, внесение удобрений.

1. Introduction

It is known from the analysis of the literature that the diameter of the disks of centrifugal devices is 400-700 mm in the world [1; p. 272]. Disc centrifugal devices with a diameter of 400-500 mm are usually installed in pairs on one fertilizing machine. Disc devices with a diameter of 600-700 mm are installed one piece per fertilizing machine.Based on the above and the size of the fields in the farms of our republic, we also adopted a disc centrifugal device with a diameter of 600 mm and decided to install one unit on the fertilizing machine.

2. Bipolar transistor radiation degradation model

It is widely used in centrifugal devices that the number of blades is four and they are placed symmetrically on the surface of the disk. Because the balance of the hardware disk at a large number of revolutions and reliable stability is required from the point of view of safety. However, there is variation in the shape of the blades and their placement relative to the radius of the disc.The basis of this diversity lies in the method of implementation of the technological process. In particular, the shape of the shovels is chosen in the form of a roll in order to reduce the friction forces during the movement of the fertilizer grains on the shovels and prevent the separation process [2; p. 784-787]. It is known that there are logarithmic, Archimedean and hyperbolic types of windings (Figs. 1.-2-3) [2; p. 784-787].

In a logarithmic winding, the angle between the product transferred to each of its points and the radius vector is constant. In this case, it is possible to select any part of the logarithmic roll whose central angle is equal to 90º. When constructing a logarithmic winding and choosing its desired section, the case where the length of the radius vector is equal to the radius of the centrifugal disk R and the corresponding section OA₀D₄ was selected..

Figure 3. Hyperbolic coil

The Archimedean coil is formed by the connection of the points formed by the increase of the radius vector OF_i in accordance with each turning angle α of the straight line UU passing through the polar axis. The change of the angle between the product and the radius vector transferred to each point of the package does not achieve the expected result by using the shape of a piece ofthis package, for example, A₂ F₃ as a shovel. Although the formation of a hyperbolic winding is different from the windings presented above, the distance of the points of the winding from the pole center is not smooth. The coil becomes larger and the asymptote of its axis becomes visible.Taking into account the above ideas and analysis, the angle between the product transferred to each point of the logarithmic coil and the radius vector will be constant. This property is not preserved in the remaining Archimedean and hyperbolic convolutions. In this case, the uniform accelerated movement of the fertilizer grains is ensured.

3. Comparative analysis of radiation hardness of the current mirrors on  bipolar transistors

Taking into account the above, a piece of logarithmic winding corresponding to the length of 0.3 m along the pole axis OX and whose central angle was 90º was selected from the center of the pole O.The relative and displacement speeds of the movement of mineral fertilizer grains on a logarithmic coil shaped shovel were calculated, and the absolute speed direction of the fertilizer grains was determined using the fact that their vector sum gives the absolute speed figure -4.The determination of the absolute velocity direction and the corresponding additional air flow pattern presented in figure 4 makes it possible to determine the location of the device that generates the additional air flow. It is necessary to choose the direction of the additional air flow to be the same as the absolute speed of the fertilizer grains, i.e. parallel. Only then will the efficiency of using additional air flow be high.To achieve this, the line KK is drawn from the bottom of the disk for the absolute speed of throwing the fertilizer grains.

Figure 4. Scheme for selecting the direction of the additional air flow according to the direction of the absolute speed of the fertilizer grain

A line AD is drawn perpendicular to KK. The length of the line AD is chosen based on the disc diameter. In this case, 0.15 m was chosen. We draw a line parallel to AD from the end point of the logarithmic roll shape of the disk and take its length as 0.05 m. Then AD:ad=3. The resulting trapezoid AadD is a top view of the device that creates the additional airflow.Taking into account that mineral fertilizer grains are thrown horizontally from the disk of the centrifugal apparatus, we direct the direction of the speed of the additional air flow and the exit from the disk along the horizontal plane. For this, we choose the shape of the base of the device, that is, the part of the base at the edge of the disc is taken parallel to the plane of the disc. This condition was ensured by choosing the height of the inlet hole of the device to be 0.10 m. Accordingly, the height of the outlet hole was chosen to be 0.03 m.

Based on the adoption of constructive technical solutions and their analysis, the width of the entrance hole is 0.15 m, the height is 0.1 m, the width of the exit hole is 0.05 m and the height is 0.03 m. The use of a logarithmic roll-shaped shovel with a convexity in the direction of rotation has been shown in previous studies to release fertilizer grains from the disc in a short time. The positive side of logarithmic roll-shaped shovels is that, firstly, mineral fertilizer grains move with minimal friction, thus preventing segregation, and secondly, they are thrown in a short time, as a result, the minimum value of the exit angle is ensured [3;p. 254-256].

                        (1)

Where y₀ is the angle between relative speed and centrifugal force, degree; S is the distance traveled along the shovel, m. The exit angle of the centrifugal device is a direct indicator that affects the uneven spreading of fertilizers. This indicator depends on the distance r₀ of feeding the fertilizer to the disc, the length of the shovel S and the angular speed ω of the disc (Fig. 5) [4; p. 10-14].

Figure 5. The scheme for determining the angles of exit and scattering of mineral fertilizer grains from the centrifugal apparatus

Mineral fertilizer grains are not given to the beginning of the shovel, but at a distance r₀ from the center of the disk, r1 is In expression (1.), S represents the total length of the spade. It is known that the initial radius of the logarithmic scroll-shaped shovel, that is, the pole radius (Fig. 6) [4; p.10-14]. It can be seen from the figure that r₀› r₁.

Figure 6. The scheme for determining the length of the shovel traveled by the fertilizer grains

The length of the arc MM1 of the logarithmic winding-shaped shovel can be determined by the following expression [5.225-227 p.]. (2) where r1 is the initial radius of the shovel, m; The angle, degrees, between the product and the radius vector transferred to any point of the psball.

The effect of the indicators in the expression (1) on the length of the path traveled by the fertilizer grains along the shovel is shown in the graphs.

The graphic disk radius presented in Figure 6 was constructed at the values R=0.3m, r₁ =0.05m and r₀=0.11m. As can be seen from the graph presented in

Figure 7. The length of the shovel increases according to the law of the curve as the angle ps increases

The length of the logarithmic winding increases due to the decrease in the radius of curvature. In this case, the time of movement of fertilizer grains along the shovel increases. This makes it possible for the fertilizer grains to separate into fractions. From this point of view, the length of the shovel was taken to be 0.22-0.23 m corresponding to the angle ps=30-35^o.

Figure 8. Shows the graph of the variation of shovel length r₀ depending on the distance of fertilizer delivery

Figure 8. The graph of the change of shovel length depending on the distance r₀ fertilizer.Figure 8 was constructed at the values   R = 0.3 m, r1 = 0.05 m and π = 30o. As can be seen from the graph presented in Figure 6, as the radius of fertilizer delivery increases, the length of the shovel, where the fertilizer grains move, decreases according to the law of a straight line. Because the fertilizer radius is getting bigger and the disc radius is getting closer to the length. Based on the results of the experimental studies carried out earlier and conducted by us, the radius of fertilizing was adopted in the range of 0.100-0.125 m.The obtained results directly affect the angles of exit and scattering of mineral fertilizer grains from the centrifugal apparatus and ultimately their uneven distribution. The exit angle of the fertilizer grains from the centrifugal apparatus (3) where t is the time the fertilizer grains moved along the shovel, sec. Figure 9 shows the graph of the variation of the angle b of fertilizer exit from the shovel depending on the angle ps. The graphic disk radius presented in figure 8 was constructed at values R=0.3m, r1 =0.05m and r0=0.11m. As can be seen from the graph presented in Fig. 9, the exit angle b increases according to the law of the curve with the increase of the angle ps.The increase in the angle ps is explained by the fact that the length of the shovel increases in the direction opposite to the direction of movement of the apparatus, that is, in order for the fertilizer grains to move and be thrown from the apparatus at this distance, it is required to turn to a large angle. For example, when ps=30^o, the output angle is b=95^o, and when ps=42^o, the output angle is equal to 120^o. From this, it was shown that when the angle of ps increases by 12^o, the output angle is doubled by 25^o.     (3)

Taking into account the results of theoretical calculations carried out by the authors and other researchers and the construction of fertilizing machines, the output angle was adopted in the range of б=95-105^o. Because increasing the angle пс from 30-35^o makes the logarithmic winding smaller in its radius of curvature, but increasing its length. will come As a result, the duration of movement of fertilizer grains along the shovel increases, and the segregation process becomes possible [6.63-65 p.].

Figure 9 presents a graph of the variation of the angle b of fertilizer exit from the shovel depending on the distance r₀ of fertilizer delivery. The graphic disk radius presented in Figure 9 was constructed at the values   R=0.3m, r₁ =0.05 m and r₀=0.11. From the graph presented in Figure 9, it can be seen that the increase in the fertilizer delivery radius decreases the exit angle. This shows that at a distance of 0.125 m, mineral fertilizer grains with friction coefficients f=0.3-0.5 have the same exit angle of 80^o.

From the moment the fertilizer grains are thrown from the apparatus, the second phase of their movement begins, that is, their movement in the environment is influenced by additional air flow. - the power of the additional air flow is directed horizontally; - the speed of the air flow does not change along the cross-sectional surface of the exit hole; - all fertilizer grains have the same exit speed and direction from the shovels. If there is no wind (the wind speed should be less than 5 m/s), the additional air flow coming out of the outlet expands proportionally to the distance to the outlet and carries the particles of the environment with it.The speed of additional air flow decreases depending on the distance [7; pp. 247-248]. and taking into account the relative movement and speed of fertilizer grains relative to it, the following expression was obtained.

                                          (4)

4) where is the distance traveled by the air flow along the axis, m; axis speed, m/s; k - air resistance coefficient; Vx – initial speed of additional air flow, m/s; α - coefficient of turbulence (eddyness) of the flow, α=0.07-0.14; x is the value of the viewed distance from the device output hole, m; d is the diameter of the exit hole, d=0.043 m. The sign "+" in the expression (3) and the sign "-" are used in cases.

The speed of the fertilizer grains changes under the influence of additional air flow. Because the value of the additional air flow speed is on average 3-4 times greater than the speed of mineral fertilizers at the time of exit from the apparatus, as well as the directions of movement are parallel to each other. Figure 11 shows the effect of additional air flow on the change in speed of fertilizer grains.

Figures 11. a, b, v show that the initial speed of fertilizer grains increases significantly under the influence of additional air flow

For example, if the initial speed of the fertilizer grain was 25 m/s, after entering the additional air stream, its speed was 42 m/s (Fig. 11 a), 53 m/s (Fig. 11b) and 70 m/s (Fig. 11 v) rising to It can be explained that the additional force of the air flow gives impulse to the fertilizer grains.

4. Conclusion

From the analysis of the graphs, it can be noticed that over time, the rate of additional air flow decreases rapidly, while that of the fertilizer grain decreases relatively slowly.

However, the fertilizer grain had a significantly higher velocity than its initial velocity when it exited the centrifuge. That is why their throwing distance is large, which makes it possible to increase the working width of the machine.

However, the fertilizer grain had a significantly higher velocity than its initial velocity when it exited the centrifuge. That is why their throwing distance is large, which makes it possible to increase the working width of the machine.

References:

1. Худаяров Б.М., Мамбетшерипова А.А. Substantiating parameters of advanced centrifugal apparatus//European science review.- Austria,2018 №9-10 p.235-237.
2. Худаяров Б.М., Мамбетшерипова А.А.Improving the tecnechological process of the fertilizer from centrifugal fertilizer apparatus and setting the parameters // ACTA TTPU.-Tashkent, 2018. №3. Р. 63-65.
3. Khudayarov B., Mambetsheripova A., Abdiganieva N. THE METHOD OF GENERATING ADDITIONAL AIR POWER IN CENTRIFUGAL APPARATUS AND ITS EFFECT ON WORK QUALITY // Universum: технические науки : электрон. научн. журн. 2022. 5(98). URL: https://7universum.com/ru/tech/archive/item/13667 (дата обращения: 27.05.2022) Худаяров Б.М.,Мамбетшерипова А.А. Центробежно-дисковые аппараты машин для внесения минеральных удобрений -Тошкент:2018.7985с.
4. Фихтенгольц Г.М. Дифференциал ва интеграл ҳисоб курси. Ўқувпеддавнашр.-Т. -1958. 225-227 б.
5. Худаяров Б.М., Мамбетшерипова А.А.Improving the tecnechological process of the fertilizer from centrifugal fertilizer apparatus and setting the parameters // ACTA TTPU.-  Tashkent,  2018. №3. Р. 63-65.
6. Кленин Н.И.,Сакун В.А. Сельскохозяйственные и мелиоративные машины. – М.: Колос, 1980. – 247-248 с.