There are now two types of studies on coal mine gas explosion suppression technology. The first kind of technology is passive explosion suppression. Technology for actively suppressing explosions is the second category. Passive explosion suppression technology is primarily accomplished by dispersing explosive suppression powder or absorbing materials to reduce the intensity of explosion flames and shock waves. Through experiments, Liu et al. [
3] investigated the effects of rock powder, water, and ABC dry powder on suppressing explosions. The findings revealed that while water and rock powder effectively suppressed shock waves and the Hull explosion flame of coal powder secondary explosion, ABC dry powder had the most effective overall suppressive effect. In order to undertake explosive suppression tests, Wang et al. [
4] created Mg (OH)
2/NH
4PO
4 composite dry powder (CDP) with various mass ratios. The findings demonstrated that CDP substantially impacted lowering the KG, Tmax, and Vmax of methane explosion. On a small-scale experimental platform, Luo et al. [
5] confirmed the inhibitory capacity of BC powder on hydrogen/methane premixed gas explosions. The findings revealed that the ideal inhibitory concentration for BC was 200 g/m
3. Experimental research on the NaHCO
3 water mist’s ability to prevent methane explosions was carried out by Wei et al. [
6]. The suppression mechanism of NaHCO
3 water mist was examined using a kinetic model. The outcomes demonstrated that the explosive’s composition, equivalent, and concentration impacted the suppressing effect. Fan et al. [
7] analyzed the effect of NaHCO
3 powder on premixed flames through experiments. The results showed that when the particle size was large, thermodynamics controlled the inhibition mechanism, mainly by physical effects. When the particle size was small, the inhibition mechanism was controlled by kinetics, and chemical reactions dominated. Using a synchronous thermal analyzer, Zhao et al.’s research [
8] on the inhibitory effect of ABC dry powder on methane/coal powder explosion revealed that ABC powder raised the initial temperature of the coal powder thermal decomposition and significantly decreased the thermal decomposition rate, heat release, and maximum heat flow rate. Using fluid mechanics and thermal analysis theory, Song et al. [
9] conducted a numerical simulation study on the impact of rock powder on gas explosion suppression. The results revealed that when the amount of rock powder was less than 12 kg/m
3, the flame in the pipeline could not be put out, and when Ningdu was 36 kg/m
3, the overpressure decreased by 40%, and the flame peak speed decreased by 50%. In a wholly enclosed visual container, Jiang et al. [
10] investigated the inhibitory impact of ultrafine water mist on methane explosions with methane concentrations of 6%, 11%, and 13%. Adding water mist lowered the maximum explosive overpressure, pressure increase rate, and flame propagation speed, according to the results. Through numerical modeling, Cao et al. [
11] investigated the inhibitory mechanism of ultrafine water mist on methane explosion. The findings indicated that heat exchange occurred mainly in the reaction zone and that ultrafine water mist successfully suppressed methane explosion. Pei et al. [
12] used a self-built water mist suppression device to perform several experimental tests on the suppression of methane explosions by water mist containing sodium chloride additions. The findings demonstrated that sodium chloride-containing water mist effectively inhibited methane explosions, primarily because the sodium chloride increased the synergistic impact of physics and chemistry. According to the properties of foam ceramics, Zhang et al. [
13] investigated the coupling mechanism of foam ceramics to gas explosion flame and shock wave. The findings demonstrated that the primary variables influencing energy absorption and dissipation were the distinctive features of the porous structure. Through experimentation, Shao et al. [
14] investigated the suppression impact of metal foam on gas explosions. The findings demonstrated that foam copper suppressed explosions more effectively at 6, 7, and 8 KPa starting pressures when placed near the ignition end. The results of a systematic study by Zhou et al. [
15] on the effects of mesh aluminum alloy (MAA) and aluminum velvet (AV) on the explosion reaction of combustible gases revealed that these materials had a dual effect of promoting and suppressing explosions. The results also revealed that the primary function of explosion suppressants was determined by the nature of the combustible gas rather than the shape of the explosion suppressor material. Through experimental and computer simulations, Cheng et al.’s [
16] study of the inhibitory impact of metal wire mesh on gas explosions revealed that metal wire mesh may efficiently reduce the flame’s temperature when premixed flames spread via a pipeline. The attenuation rate increased to 79% with the addition of three layers of 60 mesh metal wire mesh. Using a custom-made experimental apparatus, Sun et al. [
17] investigated the effectiveness of porous materials in suppressing explosions. The findings demonstrated that foam ceramic and metal mesh materials had particular pressure-reducing and flame-retardant qualities. Metal mesh has excellent resistance to impact damage. However, it has a weak flame-retardant effect. Foam ceramic has a weak resistance to impact damage but an excellent flame retardant effect. In conclusion, passive explosive suppression technology may reduce the impact of gas explosions and explosion flames to a certain amount, but it often fails after one action and cannot withstand repeated explosions.
In order to regulate the explosion suppression device and spray explosion suppressants, active explosion suppression technology primarily employs high-precision sensors to record explosion information. Using autonomous spraying experimental equipment, Jiang et al. [
18] looked into the inhibitory effects of nitrogen and ABC powder on methane explosion. The outcomes demonstrated that nitrogen and ABC powder spraying significantly reduced the overpressure of explosions and the flame propagation speed. The findings of an experiment by Chen et al. [
19] using SiO
2 powder to suppress a methane explosion indicated that SiO
2 had a robust inhibitory impact on gas explosion flames, lowering the peak pressure and flame velocity by more than 40%. Yang et al.’s [
20] experiment looked at how methane-oxidizing bacteria in ultrafine water mist affected methane explosions. According to the findings, fine water mist spraying effectively suppressed explosions, and methane-oxidizing bacteria had a part to play in the methane explanation, which enhanced the fine water mist’s suppression of the explosions’ impact. The findings of a 20 L spherical experimental setup utilized by Luo et al. [
21] to investigate the inhibitory impact of CO
2 and ABC powder on mine gas explosions revealed a synergistic effect between CO
2 and ABC powder. The findings of a study by Zhao et al. [
22] on the use of N
2/APP to suppress fires and explosions caused by methane and coal dust in vertical pipes revealed that the system could successfully stop the spread of explosive flames caused by methane and coal dust. Li et al. [
23] obtained the characteristics of explosion flames and explosion pressure through experiments by changing the equivalence ratio and water mist density. They analyzed the physical and chemical mechanisms of water mist-suppressed explosions. The results indicated that as the concentration of water mist increased, the average flame velocity, explosion peak overpressure, peak pressure rise rate, and positive pressure impulse all monotonically decreased. Jiang et al. [
24] showed that fine water mist above 800 g/m
3 could successfully inhibit detonation and ultimately led to flame extinction by using a sensor method to detect the spectrum signal of the explosion radiation to suppress methane explosions. To lessen the harm caused by gas explosions, Lu et al. [
25] investigated using nitrogen gas to stop the spread of explosions in horizontal pipes. The findings demonstrated that nitrogen gas spraying might stop explosions from spreading throughout the pipeline when the nitrogen pressure rose beyond 0.3 MPa. An active gas explosion flame detection system was created by Lu et al. [
26] and was used to automatically identify flames and spray extinguishing chemicals following a gas explosion. The findings showed that using ABC dry powder successfully put out explosion flames and that raising nitrogen pressure lowered the concentration of flammable gases in the pipeline. Using tests, Wang et al. [
27] investigated the inhibitory impact of water mist containing KCL and N
2 on methane explosions. The results revealed that CO
2 inhibited the flame temperature better than water mist, while the water mist containing KCL and KCL inhibited shock wave overpressure and flame velocity more significantly. Active explosion suppression technology uses sensors to collect explosion information and a control system to direct the injection system to generate an explosive suppression region. It has the power to suppress many explosions, but it demands high system stability and a high cost, making it difficult to popularize. As a result, robust, dependable, and comprehensive explosion suppression technology is critical for coal mine safety.
There are several varied cross-sections in coal mine underground tunnels and mining processes. Therefore, considering the absolute engineering quantity and efficiency, the best length is 500 mm. The cavity’s length and diameter significantly influence the explosion shock wave and flame, even leading to the explosion being enhanced. As a result, this research can help direct coal mining.
Using self-built large-scale explosion experimental equipment, the authors of this paper conducted explosive suppression tests on straight pipes and cavities 58, 55-35, 58-35, and 85-35. Ansys Fluent was used to investigate the shock wave propagation patterns in cavities 58-58 and 58-58-58, 58-58-58-58, and 58-58-58-58-58. The wave suppression effects of various types of cavities and the propagation laws and processes of shock waves in various cavities were computed. The best form of the cavity with the best explosion suppression effect was summarized, as was the link between the shock wave suppression rate and the number of cavities. This paper provides a reference for the future building of underground tunnel explosion suppression systems in coal mines.