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Simulation test of gas agitation of solid particles in a combustion tank using a GW water ejector

Simulation test of gas agitation of solid particles in a combustion tank using a GW water ejector

Chengdu Green Water Technology Co., Ltd.
Chengdu Greenwater Technology Co., Ltd. Address: Room 317-319, Building B, Gaofa Building, No. 6 Jiuxing Avenue, High-tech Zone, Chengdu Postcode: 610041 Tel: 028-85130135 Fax: 028-85195416 E-mail: jane1984@cd-greenwater.com http://www.cd-greenwater.com
Simulation test of gas agitation of solid particles in a combustion tank using a GW water ejector
1. Experimental purpose:
1. Measure the amount of air inhaled by the Venturi water ejector during gas injection;
2. Simulate the stirring effect of the Venturi gas jet on the fuel particles, and observe the loosening and prying of the particles by the GW water ejector jet.
2. Experimental model
1. Geometric model: The customer uses a φ2000mm cylindrical tank with four GW water ejector installed around it. Now a 1000×1000×1000mm glass tank is used to simulate the working conditions and scope of one of the GW water ejector. The container is made of glass material for easy observation.
2. Fuel particles: The customer uses coal particles with a particle size of 2mm and a bulk density of 1200kg/m³.
Considering that the temperature inside the tank during actual combustion is >1000°C, the bulk density of fuel particles will be greatly reduced. Therefore, the experiment uses particles with a particle size of 2mm and a bulk density of 350~450kg/m³ to simulate actual working conditions.
3. Motive gas: The customer uses oxygen as the motive gas, and the experiment uses air as the motive gas. The oxygen density is
1.4kg/m³, air density is 1.23kg/m³, the two densities are similar, so they can simulate actual working conditions.
4. The experiment uses 0.1MPa~0.4MPa compressed air for spray stirring simulation, and the working conditions under different pressures can be observed.
3. Experimental device
1. Device introduction:
①Air pressure device: Provides 0.5MPa motive air;
②Valve A: Pressure tank control valve, adjusts the gas pressure of the pressure tank;
Chengdu Green Water Technology Co., Ltd.
Chengdu Greenwater Technology Co., Ltd. Address: Room 317-319, Building B, Gaofa Building, No. 6 Jiuxing Avenue, High-tech Zone, Chengdu Postcode: 610041 Tel: 028-85130135 Fax: 028-85195416 E-mail: jane1984@cd-greenwater.com http://www.cd-greenwater.com
③ Pressure stabilizing tank: adjusts the air pressure to provide stable pressure motive air for the injection experiment;
④Valve B: GW water ejector air intake control valve;
⑤Flowmeter A: DN50 vortex flowmeter, measuring the flow rate of the GW water ejector inlet motive air; the factor that has a greater impact on the vortex flowmeter is the fluid pressure, so the pressure value of the flowmeter needs to be adjusted before each measurement;
⑥GW water ejector: sprays air to stir the particles and inhale air at the same time;
⑦Glass tank: loaded with particles, the glass is transparent for easy observation;
⑧Pressure gauge: measures the pressure of the motive air in the pressure tank;
⑨Flowmeter B: DN25 vortex flowmeter, measuring the suction volume of GW water ejector;
2. The experimental device connections are shown in Figures 1, 2, and 3.
8 pressure gauge
9 flow meter B
3 pressure tank
7 glass jar
Inhale air
1 air pressure device
Motive air
DN50 pipe
5 flow meter A
2 Valve A
4 Valve B
6GW water ejector
Figure 1 Schematic diagram of experimental device
Chengdu Green Water Technology Co., Ltd.
Chengdu Greenwater Technology Co., Ltd. Address: Room 317-319, Building B, Gaofa Building, No. 6 Jiuxing Avenue, High-tech Zone, Chengdu Postcode: 610041 Tel: 028-85130135 Fax: 028-85195416 E-mail: jane1984@cd-greenwater.com http://www.cd-greenwater.com
①Air pressure device interface
②Valve A
⑧Pressure gauge
③ Pressure stabilizing tank
⑤Flowmeter A
⑨Flowmeter B
⑦Glass tank
⑤Flowmeter A
④Valve B
⑨Flowmeter B
⑥GW water ejector
Figure 2 Overall experimental device diagram
Figure 3 Partial device diagram
4. Experimental steps and processes
1. Air entrainment
After installing the apparatus as shown in Figure 2, adjust valve A to stabilize the pressure in the pressure tank at 0.04MPa, 0.05MPa or other selected values. Open valve B to inject air. Once the pressure gauge and
Chengdu Green Water Technology Co., Ltd.
Chengdu Greenwater Technology Co., Ltd. Address: Room 317-319, Building B, Gaofa Building, No. 6 Jiuxing Avenue, High-tech Zone, Chengdu Postcode: 610041 Tel: 028-85130135 Fax: 028-85195416 E-mail: jane1984@cd-greenwater.com http://www.cd-greenwater.com
flowmeter readings have stabilized, record the data. The measurements are shown in Table 1.
Table 1
Under different pressure conditions, the air flow through the GW water ejector is different, and the amount of air inhaled by the GW water ejector is also different. When the pressure is 0.2MPa, the flow rate reaches 670m³/h, and the GW water ejector no longer sucks air. Since the pressure gauge cannot accurately display the pressure of 0~0.04MPa, the vortex flowmeter cannot work properly and cannot measure the inlet flow of the GW water ejector. The maximum value of the suction volume measured at 0.04MPa is 30.3m³/h.
2. Air jet mixing
The experiment is divided into four groups. The particle thickness continues to increase, which are 300mm, 500mm, 700mm, and 800mm (from the bottom of the particle thickness container to the upper surface of the particle pile). The motive air is controlled between 0.1 and 0.4MPa, and the stirring phenomenon is observed. The observation results are shown in Table 2.
No.
GW water ejector inlet
GW water ejector air intake
Pressure MPa
Flow rate (m³/h)
Flow rate (m³/h)
1
0.04
166
30.3
2
0.05
185
25.8
3
0.08
352
20.1
4
0.1
440
17.8
5
0.15
562
12.3
6
0.2
670
0
7
0.3
960
0
Chengdu Green Water Technology Co., Ltd.
Chengdu Greenwater Technology Co., Ltd. Address: Room 317-319, Building B, Gaofa Building, No. 6 Jiuxing Avenue, High-tech Zone, Chengdu Postcode: 610041 Tel: 028-85130135 Fax: 028-85195416 E-mail: jane1984@cd-greenwater.com http://www.cd-greenwater.com
Table 2
No.
Particles
Motive air
Agitation observations
Remarks (click to watch video)
Thickness (mm)
Mass (kg)
Pressure (MPa)
1
300
100
0.1
The pile of particles is sprayed open, and the particles hit the back plate of the glass tank with the airflow and spread around.
300mm0.1MPa.MOV
2
0.2
The pile of particles is quickly sprayed away, and the particles hit the back plate of the glass tank violently with the airflow and scatter around.
300mm0.2MPa.MOV
3
500
175
0.1
The inside of the particle pile is fluffy, the particles are floating, and the particles can be observed from the bottom to be rolling continuously.
500mm0.1MPa.MOV
4
0.2
The particle pile initially arches upward, and then the particles are ejected upward like a volcanic eruption along with the air flow.
500mm0.2MPa.MOV
5
0.4
The airflow passes through the front and back of the container, and the particles are sprayed violently. From the rear view of the glass tank, a large number of particles can be seen rising up and rolling violently. The stirring range is shown in Figure 4.
500mm0.4MPa.MOV
6
700
250
0.2
The particles float upward as a whole, and a particle pile with a diameter of more than half a meter protrudes above the water ejector nozzle (as shown in Figure 5). It can be observed that there is a large gap in the middle of the particles, and the particles are stirred in the gap. As the protruding particle pile continues to expand, the particles finally spray upward with the air flow like a volcanic eruption. The feed pile after stopping the air intake is shown in Figure 6.
700mm0.2MPa.MOV
7
0.4
The particles are ejected upward with the air flow like a volcanic eruption, and the stirring traces are shown in Figure 7.
700mm0.4MPa.MOV
8
800
300
0.4
particles are ejected upward with the air flow like a volcanic eruption
800mm0.4MPa.MOV
Chengdu Green Water Technology Co., Ltd.
Chengdu Greenwater Technology Co., Ltd. Address: Room 317-319, Building B, Gaofa Building, No. 6 Jiuxing Avenue, High-tech Zone, Chengdu Postcode: 610041 Tel: 028-85130135 Fax: 028-85195416 E-mail: jane1984@cd-greenwater.com http://www.cd-greenwater.com
Blowing loose area
Figure 4 Movement traces of 500mm thick 0.4MPa pressure particles
Note: The traces of particle movement in the picture indicate that the air flow traverses the particle pile and agitates the particle material as a whole.
Chengdu Green Water Technology Co., Ltd.
Chengdu Greenwater Technology Co., Ltd. Address: Room 317-319, Building B, Gaofa Building, No. 6 Jiuxing Avenue, High-tech Zone, Chengdu Postcode: 610041 Tel: 028-85130135 Fax: 028-85195416 E-mail: jane1984@cd-greenwater.com http://www.cd-greenwater.com
Figure 5 Schematic diagram of the state of particles under 700mm thickness and 0.2MPa pressure
Figure 6 Schematic diagram of particle state after stopping ventilation at 700mm0.2MPa pressure
Figure 7 700mm0.4MPa stirring traces
Chengdu Green Water Technology Co., Ltd.
Chengdu Greenwater Technology Co., Ltd. Address: Room 317-319, Building B, Gaofa Building, No. 6 Jiuxing Avenue, High-tech Zone, Chengdu Postcode: 610041 Tel: 028-85130135 Fax: 028-85195416 E-mail: jane1984@cd-greenwater.com http://www.cd-greenwater.com
5. Experimental conclusion
1. Air entrainment
There are no particles in the glass tank and the GW water ejector outlet is in a resistance-free state. By adjusting the pressure of different motive air, the different flow rates and corresponding suction volumes of the GW water ejector are measured:
① When the pressure of the motive air is less than 0.04MPa and the flow rate of the GW water ejector air inlet is less than 166m³/h, the suction volume of the GW water ejector increases as the air pressure increases and the flow rate increases.
② When the pressure of the motive air is 0.04MPa and the flow rate of the GW water ejector air inlet is 166m³/h, the measured maximum air suction volume of the GW water ejector is 30.3m³/h.
③When the pressure of the motive air is greater than 0.04MPa, and the flow rate of the GW water ejector air inlet is greater than 166m³/h, the suction volume decreases as the air pressure increases and the flow rate increases.
2. Jet stirring
Experiments have shown that when solid particles are injected with gas using a GW water ejector, when the gas pressure is 0.1MPa, the inside of the particle pile becomes fluffy, and the particles float and roll continuously (as shown in the video at 500mm, 0.1MPa and 50 seconds). When the gas pressure is 0.2MPa, the particles will float up with the airflow as a whole, forming a large gap in the middle and showing a fluffy shape (such as the video of 700mm0.2MPa for 2 minutes). After a period of time, the particles will erupt upward like a volcano. When the gas pressure is greater than 0.2MPa, the particles immediately eject and flip upward like a volcanic eruption.
At room temperature, the GW water ejector spray stirs the particles. The air pressure of 0.1~0.2MPa can lift the particles as a whole, forming a gap in the middle, and the particles continue to tumble. After a period of time, the particles are ejected upward like a volcanic eruption. In order to achieve a good stirring effect of fuel particles during combustion, it is only necessary to make the particles fluffy and form gaps in the middle. It does not require violent stirring like a volcanic eruption, so the stirring effect can be achieved by using an air pressure of less than 0.1MPa. In the high-temperature combustion state, the gas expands rapidly when heated,
Chengdu Green Water Technology Co., Ltd.
Chengdu Greenwater Technology Co., Ltd. Address: Room 317-319, Building B, Gaofa Building, No. 6 Jiuxing Avenue, High-tech Zone, Chengdu Postcode: 610041 Tel: 028-85130135 Fax: 028-85195416 E-mail: jane1984@cd-greenwater.com http://www.cd-greenwater.com
To make the particles fluffy, the pressure and flow rate of the required motive air will be smaller than the pressure and flow rate at normal temperature.
GW water ejector can achieve good results when used to stir solid particles and gases in combustion tanks.
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