Impact of gas density, leakage pressure, and solid content on gas plume dynamics in soil slurries: A holistic perspective of underwater pipeline leaks

• Underwater pipelines are crucial for energy transport, but exposed to harsh conditions. • Gas density plays a crucial role in underwater plume formation due to buoyancy effect. • Increasing leakage pressure is likely to cause rapidly rising, larger underwater plumes. • High solid content in the surrounding fluid medium typically hinders plume formation. • Gas density, leak pressure, and environment affect underwater pipeline leak severity. Underwater gas pipelines are vital for energy transportation but are often subjected to harsh environments, and any leakage can have significant environmental consequences. Substantial underestimation of gas plume formation resulting from subsea pipeline leakage can severely affect on-site personnel and the surrounding marine environment. Current studies mainly demonstrate the impact of leakage conditions on underwater gas plume formation while neglecting the impact of suspended sediments in natural muddy water. Using comprehensive experiment-based numerical parametric evaluations, this research investigates the relationship between gas leakage parameters (gas density and leakage pressure) and its leaking environment (solid content) on the gas plume dynamics in soil slurry. The methodology involves computational fluid dynamics (CFD) simulations calibrated using experimental measurements to achieve the research objective. Our findings highlight gas density as the primary factor driving plume formation through buoyancy. Higher gas densities result in longer rising times, lower fountain heights, and smaller plume diameters due to decreased buoyant force. Additionally, increasing leakage pressure can enhance plume formation by facilitating faster rises, as well as increasing fountain heights and diameters due to increased gas momentum. Increasing solid contents in the surrounding fluid medium significantly hinders plume formation, resulting in longer rising times and smaller plume dimensions due to increased drag. With the growing demand for hydrogen-based fuel gas transportation and potential changes in the transport environment, the established relationship from this research can provide insights into a comprehensive and holistic risk assessment of underwater gas pipeline leaks, further enhancing process safety and environmental factors.