Investigation on the atomization characteristics of a solid-cone spray for dust reduction at low and medium pressures

Abstract Pressure nozzle is commonly used in the dust-reduction techniques by spraying of underground coal mines. Based on the internal structure, the pressure nozzle can be divided into the following types: spiral channel nozzle, tangential flow-guided nozzle and X-swirl nozzle. In order to provide better guidance on the selection of nozzles for the coal mine dust-reduction systems by spraying, we designed comparing experiments to study the atomization characteristics and dust-reduction performance of four commonly used nozzles in the coal mine underground with different internal structures. From the experimental results on the atomization characteristics, both the tangential flow-guided nozzle and the X-swirl nozzle have high flow coefficients. The atomization angle is the largest in the spiral non-porous nozzle, and smallest in both the X-swirl nozzle and the spiral porous nozzle. The spraying range and the droplet velocity are inversely proportional to the atomization angle. When the water pressure is low, the atomization performance of the spiral non-porous nozzle is the best among the four types of nozzles. The atomization performance of the X-swirl nozzle is superior to other types when the water pressure is high. Under the high water pressure, the particle size of the atomized droplets is smallest in the X-swirl nozzle. Through the experiments on the dust-reduction performance of the four types of nozzles and the comprehensive analysis, the X-swirl nozzle is recommended for the coal mine application site with low water pressure in the dust-reduction system, while at the sites with high water pressure, the spiral non-porous nozzle is recommended, which has the lowest water consumption and obvious economic advantages.

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Experimental study on atomization characteristics of two common spiral channel pressure nozzles

E3S Web of Conferences ◽

10.1051/e3sconf/20198101022 ◽

2019 ◽

Vol 81 ◽

pp. 01022 ◽

Cited By ~ 1

Author(s):

Han Han ◽

Pengfei Wang ◽

Ronghua Liu ◽

Yongjun Li ◽

Jan Wang ◽

...

Keyword(s):

Droplet Size ◽

Working Environment ◽

Flow Coefficient ◽

Water Droplets ◽

Reduction Efficiency ◽

Atomization Characteristics ◽

Spiral Channel ◽

Dust Reduction ◽

Type Pressure ◽

Channel Type

Spiral channel pressure nozzles are commonly used pressure nozzles in practical workplaces. In this paper, two kinds of spiral channel type pressure nozzles, namely, spiral hole type and spiral non-porous type, the atomization characteristics and dust reduction efficiency under different spray pressures are discussed and compared. Based on the experimental method, based on the self-designed spray dust-reducing roadway experimental platform, the macro-atomization characteristics of the two nozzles, namely the flow rate, the atomization angle, the range, and the droplet size, were measured. The following conclusions were drawn: (1) The flow rates of both nozzles increase with increasing spray pressure, and the flow coefficient of the spiral non-porous nozzle is small. (2) The change of the atomization angle of the two nozzles first increases and then decreases with the increase of the spray pressure, and the atomization angle of the spiral non-porous nozzle is larger. At the same time, the range of the two nozzles gradually increases as the spray pressure increases, and the range of the spiral perforated nozzle is always larger than that of the spiral non-porous nozzle. (3) When the spray pressure is gradually increased, the droplet size of the two nozzles selected in the experiment is gradually reduced, and the droplet size of the spiral perforated nozzle is always larger than that of the spiral non-porous nozzle before 5 MPa, and then gradually Become smaller. The main reason why the droplet size decreases with the increase of the spray pressure is that the increase of the spray pressure leads to an increase in the spray speed of the water droplets, so that the water droplets are completely split when they are ejected from the nozzle, resulting in a smaller droplet size. In summary, when the spray pressure required in the actual working environment is low, the use of a spiral non-porous nozzle is more conducive to dust reduction.

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