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UNIVERSUM:
, ТЕХНИЧЕСКИЕ НАУКИ_январь. 2023 г.
DOI - 10.32743/UniTech.2023.106.1.14903
RESISTANCE COEFFICIENTS OF THE APPARATUS WITH CONE MESH WET CLEANING
OF DUST GASES
Ikromali Karimov
Doctor of Technical Sciences (DSc), Associate Professor, Fergana Polytechnic Institute, Republic of Uzbekistan, Fergana
Bobirmirzo Qo'chqarov
Assistant,
Fergana Polytechnic Institute, Republic of Uzbekistan, Fergana E-mail: [email protected]
№ 1 (106)
КОЭФФИЦИЕНТЫ СОПРОТИВЛЕНИЯ АППАРАТА С КОНУСНОЙ СЕТКОЙ ВЛАЖНОЙ ОЧИСТКИ ОТ ПЫЛЕВЫХ ГАЗОВ
Каримов Икромали Тожиматович
д-р техн. наук, доц., Ферганский политехнический институт, Республика Узбекистан, г. Фергана
Кочкаров Бобирмирзо Улугбекович
помощник,
Ферганский политехнический институт Республика Узбекистан, г. Фергана
ABSTRACT
The article presents the results of an experimental study conducted on a pilot plant with a mesh cone for wet dust cleaning. In the studies carried out, the local resistances of the devices and the resistance coefficients of the selected three different-sized grids were determined in the absence of splashing of the device with water, at variable gas flow rates. Based on the research results, the values of correction factors for calculating the resistance coefficient of the selected grids were determined. As a result, it was possible to calculate the total pressure loss depending on the total resistance coefficient in the contact devices of the apparatus.
АННОТАЦИЯ
В статье представлены результаты экспериментального исследования, проведенного на опытной установке с сетчатой конусом мокрого пылеочистки. В проведенных исследованиях определены местные сопротивления аппаратов и коэффициенты сопротивления выбранных трех разно размерных сеток в условиях отсутствия забрыз-гивания устройства водой, при переменных значениях расхода газа. По результатам исследований определены значения поправочных коэффициентов для расчета коэффициента сопротивления выбранных сеток. В результате создано возможности рассчитать суммарные потери давления в зависимости от коэффициента полного сопротивления в контактных устройствах аппарата.
Keywords: dusty gas, gas velocity, flow rate, wet method, liquid, cone mesh, resistance coefficient, correction factor.
Ключевые слова: запыленный газ, скорость газа, расход, мокрый способ, жидкость, конусная сетка, коэффициент сопротивления, поправочный коэффициент.
Introduction
The cheapest and most convenient way to clean dust and toxic gases in gas is the wet cleaning process. The essence of wet cleaning of dusty gases is to combine fine dispersed dust particles by wetting the dust particles. In
this case, the contact of dust particles occurs on the surface of a liquid film or liquid droplets. In the implementation of this process, the flow of gas and liquid can move perpendicularly or oppositely [1,7].
If we analyze these devices from the point of view of constructive structure and efficiency, the indicator of
Библиографическое описание: Karimov I.T., Qo'chqarov B.U. RESISTANCE COEFFICIENTS OF THE APPARATUS WITH CONE MESH WET CLEANING OF DUST GASES // Universum: технические науки : электрон. научн. журн. 2023. 1(106). URL: https://7universum.com/ru/tech/archive/item/14903
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UNIVERSUM:
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cleaning various industrial dusts is 97-99%. But the complexity of the structural structure of these devices, the energy spent on them, and the high hydrodynamic and aerodynamic resistance in the device can be pointed out as a general drawback [1,3,4,7]. In order to eliminate the aforementioned shortcomings and to increase the contact surface between the dusty gases and the liquid supplied to the device, a new design of the dusty gas cleaning device was recommended [3,4]. Below is a diagram of the device (Fig. 1).
Research object
As an object of research, the experimental device of the cone meeting device created at the department of "Technological machines and equipment" of Fergana Polytechnic Institute (Fig. 2) and the formula for calculating the total resistance coefficient lost in the device [3,4], which was created as a result of theoretical research, were used.
1- lower conical sludge bath, 2- upper conical cleaning chamber, 3- conical screen, 3a-screen support, 4-water sprinkling nozzle, 5-water distribution pipe, 6- powder gas inlet pipe, 7- cleaned gas discharge pipe, 8- water tank, 9- water drum, 10-water pipe, 11-water rotameter, 12- sludge discharge pipe, 13- sludge drum, 14- sludge, 15-dust air driving fan, 16- dust air bag, 17 - rotameter, 18- dust gas transfer pipe
Figure 1. Schematic of the device with a cone
a) 6)
Figure 2. Overview of the cone-shaped apparatus
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Technical indicators of the device with a cone
1. Volume of dust hopper V=0.000836 m3
2. Vacuum pipe
2.1. Diameter dc = 100 mm
2.2. Length Ls = 250 mm
3. Dust air intake pipe
3.1. Diameter Dk = 100 mm
3.2. Length Lk = 150 mm
4. Purified air exhaust pipe
4.1. Diameter Dch = 200 mm
4.2. Length Lch = 200 mm
5. Device dust cleaning chamber
5.1. Height Ht= 900 mm
5.2. Large base radius Rt =350 mm
5.3. Small base radius rt =100 mm
5.4. Volume V=0.157785 m3
6. one with mesh
6.1. Height Hk= 700 mm
6.2. Large base radius Rk =350 mm 6.3 Small base radius rk =45 mm
6.4. Grid dimensions. a=1,1mm; a=1,3mm; a=1,6mm.
6.5. Mesh cone volume V=0,1027748 m3
6.6. The side surface of the netted cone, Sside = 0.9178 m2
6.7. Cone maker with mesh, l=740mm
7. Water sprinklers
7.1 Number of sprinklers, n=12 7.2. Hole diameter, dsh=1 mm.
8. Liquid rotameter PC-3
9. Water pump: GVSm 370
9.1. Power: N=0.37 kW/h
9.2. The number of rotations m=2900 0 r/min.
10. Fan: Model: DF-7
10.1. Power: N= 550w
10.2. The number of rotations n2=2800 r/min.
11. Overall dimensions of the device
11.1. Height H = 2600 mm
11.2. Width B=1160 mm
12. Water tank
12.1. Length L=0,6 mm
12.2. Width B=0,3 mm
12.3. Height H=0,4 mm
12.4. Volume V=0,072 m3
13. Sludge bath
13.1. Length L=0,6 mm
13.2. Width B=0,3 mm
13.3. Height H=0,4 mm
13.4. Volume V=0,072 m3
The obtained results
To calculate the total pressure lost in the apparatus, it is necessary to determine the local resistance of the apparatus and the coefficients of resistance of metal grids with different hole sizes, which are installed on the metal drum, which is the main working body of the apparatus. Therefore, GOST 3826-82, 12X18N10T stainless steel mats made of square holes of 3 different sizes were selected in experimental studies (Fig. 2, b). Grid dimensions 1. Square hole size a=1.1 mm, wire thickness 6=0,16mm; 2. Square hole size a=1.3 mm, wire thickness 6=0,18 mm; 3. Square hole size a=1.6 mm, wire thickness 6=0,2 mm;
The theoretical total resistance coefficient of the device is equal to the following [3].
Zen = 4 + 4 + 4
(1)
where ^ is the coefficient of internal friction when transferring dusty air to the device through a pipe, defined as follows [5,6,7].
4 =
Л
21
D + d
(2)
where is the coefficient of friction with the pipe wall introducing dust gas into the device, l- is the length of the pipe through which dust gas is moving, m; D-section cone base diameter, m; d-is the diameter of the truncated part of the cone.
& - is the resistance coefficient of the drum mesh and is determined as follows. From Fig. 1 and 2, the total resistance coefficient of the truncated conical grid
on the A-A section is determined as follows depending on the total surface of the grid through which dusty air passes and the diameter of the wire of the grid and the dimensions of the square holes of the grid [3,4] m2;
= Ak
tt( R + r ) • l
S
a
(3)
where Ak is the correction coefficient, determined through experiments, R- is the radius of the base of the conical grid, m; r-radius of the cut part of the conical mesh, m; lc - the average value of the length of the circle of the base of the mesh and the length of the circle of the cut part, m; S -grid wire diameter, m; a- mesh square hole dimensions, m.
^ch - when dusty air is discharged from the device through a pipe, the coefficient of internal friction is defined as follows [5,6,7].
d
(4)
where X2 is the coefficient of friction in the pipe for releasing the purified air from the device; l- is the length of the pipe through which the purified air moves, m; d-pipe diameter, m;
If we add the values of formulas 2, 3, 4 -to the above-mentioned formula 1, it will look like this.
4gen
Л
21
d+d
+ Ak
tT(R + r) • / •
+ Л
I ' d
(5)
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Through this equation, the total resistance coefficients of the apparatus are determined.
At the initial stage of the experiments, a damper (moving barrier) was installed on the gas suction part of the fan that transmits the dust gas to the apparatus. The damper was changed in the range of 30^90° (with 150 steps) and the gas velocities coming out of the fan and the corresponding gas consumption were determined.
According to it, when Shiber is opened to 30°, Qg=170m3/h, when opened to 45°, Qg=340m3/h, when opened to 60°, Qg=510m3/h, when opened to 75°, Qg=680m3/h, when opened to 9°°, Qg=85°m3/h. In the next course of experiments, a fan was installed in the apparatus body, and the above-determined gas consumption was given as Q=170^850 m3/h (with a step of 17° m3/h), and the gas consumption was determined by the gas velocities coming out of the apparatus.
In this case, Shiber was Qg=1°7m3/h when opened to 3°°, Qg=22°m3/h when opened to 45°, Qg=318m3/h when opened to 6°°, Qg =438m3/h when opened to 75°, Qg =512m3/h when opened to 9°°. The local resistance coefficient of the device was determined from the difference in gas consumption. Anemometer VA°6-TROTEC brand electronic device was used to determine these differences at all stages of experiments. The average local resistance coefficient of the device was x=°.6. At the next stage of the experiments, cones with a square hole size a=1,1; 1,3; 1,6 mm were installed in the apparatus body in a row (Fig. 2b)
Q=170-850 m3/hour (with a step of 17° m3/hour) was supplied to each gas drum installed in the apparatus. Experimental studies were carried out separately for each cone grid. In the experiments, the gas density was chosen at pg=1,29 kg/m3 (for air). According to the results, the resistance coefficient ^ =2,6 when the mesh square hole size is a=1,1mm, the thickness of the mesh wire is ô=°,16mm; ^ = 2.5 when the hole size is a=1,3mm, the mesh wire thickness is ô=°,18mm; hole size a=1,6mm, mesh wire thickness ô =°,2mm ^c=2,2.
These determined resistance coefficients are the overall resistance coefficient of the apparatus, plus the local resistance coefficients of the apparatus. If we subtract the local resistances from these values, the grid resistance coefficients are derived. The local resistance coefficient is determined as follows.
4 = 4 +4f )
4с = 4gen — ( 4K + 4f )
(6)
(7)
a=1, 1mm, when the mesh wire thickness is 6=0,16 mm;
5o=^gen- ^m=2,6-0,6=2
a=1,3mm, when the mesh wire thickness is 6=0,18mm; ^gen- ^=2,5-0,6=1,9
a=1,6mm, when the mesh wire thickness is 6=0,2 mm
^0= ^gen- §m=2,2-0,6=1,6
The obtained experimental results were processed on the basis of a computer program and a graph of dependence was built (Fig. 4).
A view of the resulting regression equation:
1. y = 20,388x - 0,9395 R2 = 0,9881
2. y = 20,388x - 0,3395 R2 = 0,9881
Figure 3. Graph of variation of resistance coefficient Çgen and Çc depending on Zô/Za (in the case of no liquid spraying)
Based on experimental studies, research was conducted to determine the values of the correction coefficient Ak depending on the resistance coefficient of the recommended grids. Relative resistance coefficients of selected grids were determined. Below is the calculation method.
1- calculation of a truncated conical grid. Wire thickness- S = 0,16mm ,Hole size k = 1, (1).
First of all, we take a square shape with sides of 1° sm by 1° sm as a sample.
Figure 4. Graphic image
О10 _ С _l с
Ssim = Ssim + S solid
8)
= 0,95м2 ; S1? = 10000мм2 = S_ + S^ ;
a = 0,16 • 90 = 14,4мм ; a = 0,16 • 90 = 14,4 мм.
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SZ = (ai + a2) -100 мм = = (14,4 +14,4) -i 00 мм = 2880мм:
S
950000мм: 10000мм2
= 95
There are 95 check boxes in total where: Sside - the side surface of the truncated cone surrounded by mesh,
S]0 -10 cm. a surface covered with wires at a distance
of 10 cm, a surface covered with wires at a distance of 10 cm
S-10 cm and a surface covered with empty
cells,
a - the total thickness of the wires on one side of
the isolated mesh sample, a - the total thickness of the wires on the other side of the isolated mesh sample, SSim - the surface covered by the wire in the isolated
sample, S - the sum of the areas of the empty cells
in the isolated sample.
To find the total area covered by wire in the net, we
multiply 95 pieces by S]0 -(that is, the size of the surface
of 10 cm by 10 cm):
s = S10 • S
sim. gen sim 10
(9)
S,m.gen = Si - S10 = 2880 - 95 = 273600мм2.
To find the surface occupied by the total empty
cells, we subtract the total surface covered by S wire from the S surfaces:
sim. gen
That is:
S = S — S
box. gen side sim. gen
Here ¿>H - is the relative resistance coefficient of the grid, S - we determine the total surface covered by the wire in the mesh wrapped around the side surface of the truncated cone by the ratio of S -
the total free cells in the mesh wrapped around the side surface of the truncated cone by the ratio of the surface (non-wired part):
e = Ssim-gen = 273600 = Q 40449 Sbox gen 676400 '
We determine the correction coefficient AK.
AK = L
L
(11)
To do this, we divide the experimental resistance coefficient Ç by the relative resistance coefficient §n.
AK = L =
2
= 5
4 0,4
The correction factors for subsequent grid sizes were also determined in the same way. The size of the square hole of the mesh is a=1,3mm. The thickness of the mesh wire is 8 =0,18 mm. when AK =5,1. The size of the square hole of the mesh is a=1,6mm. When the thickness of the mesh wire is 8=0.2 mm, the correction factor is equal to AK =5. For selected grid sizes, it is recommended to take the correction factor in the range AK=(5-5.1).
To simplify calculations, the coefficient of local resistance in the inlet and outlet pipe of dusty air to the device was ^m=0.6. In that case, formula 5, which calculates the total resistance of the device, will look like this.
= 950000мм2 - 273600мм2 = 676000мм2
Lgen = 0,6 + Ak
7ü(R + r)-1 -S
(12)
So: S^ = 676000mm2 ; S^ = 273600mm2 ; Sside = 950000mm 2.
Here: S - Cut is the surface occupied by the
total number of empty cells in the mesh wrapped around the side surface of the cone (wireless part).
S - The total surface covered with a wire mesh wrapped around the side surface of a truncated cone.
SSide - the side surface of a truncated cone surrounded by mesh.
We find the coefficient, of relative resistance of the set:
Summary
As a result of experimental studies, the local resistances of the arrarat and the resistance coefficients of the selected three different sizes of grids were determined in the condition that the device was not sprinkled with water, at step variable values of gas consumption. According to the results of the study, the values of the correction coefficients for calculating the resistance coefficient of the selected grids were determined. As a result, it is possible to calculate the total lost pressure depending on the total resistance coefficient in the contact devices of the apparatus.
L
S
sim. gen
box. gen
10)
S
10
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UNIVERSUM:
, ТЕХНИЧЕСКИЕ НАУКИ_январь. 2023 г.
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