NUMERICAL SIMULATION OF METHANE-AIR MIXTURE EXPLOSION IN A 40 M UNDERGROUND TUNNEL

• Main Author: Pratyaksa, Arga
• Format: Final Project
• Language: Indonesia
• Subjects: Pertambangan dan operasi berkaitan
• Online Access: https://digilib.itb.ac.id/gdl/view/53728
• Institution: Institut Teknologi Bandung

Methane gas explosion is one of the biggest causes of death in underground mines. Methane gas explosion happened at several underground coal mine around the world, such as Upper Big Branch mine accident in United States (2010), Ulyanovskaya mine accident in Russia (2007), and Sago mine accident ini United States (2006). The explosion was the result of basic system failures that allowed methane gas to build up and reach the explosive threshold. The concentration range which methane gas explosion occurs is when the concentration of methane mixed in the air is within range of 5 to 15 percent. This research aims to understand the process of methane gas explosions in a 40 m underground tunnel with a methane concentration of 6%, 9.5%, and 12% and to compare the results of research with previous studies using a 20 L confined spherical explosion chamber and a confined laboratory scale tunnel explosion chamber. Results comparison was conducted on 9.5% methane concentration. This research was conducted using numerical modeling computational fluid dynamics with ANSYS Fluent software. The geometry of the explosive chamber in this study uses a 40 m length tunnel model with 4 x 3 m tunnel face dimension that represent underground mine tunnel. Based on the research conducted, the methane gas explosion produced maximum explosion overpressure varied between 473.877 Pa, 678.271 Pa, and 664.054 Pa (Methane concentration of 6%, 9.5%, and 12% respectively). Maximum temperature varied between 1.438 °C, 2.086 °C, and 2.025 °C (Methane concentration of 6%, 9.5%, and 12% respectively). The highest explosion overpressure and maximum temperature obtained from 9.5% methane concentration. In addition, result comparison of this research with Agustinus (2020) and Peramesti (2020) research shows that confinement plays significant role to generate higher explosion overpressure. Agustinus and Peramesti research produced similar maximum explosion overpressure to this research even though simulated on smaller explosion model. This research hopefully can raise awareness on severity of methane explosion in underground mine tunnel.