Numerical simulation of methane explosion suppression by ultrafine water mist in a confined space.

• Numerical model of methane explosion inhibition by the water mist was established. • Calculation result was validated by experiment through pressure and flame changes. • Heat transfer between water mist and explosion flame was analyzed quantitatively. • Vapor pressure as a component of explosion pressure in a closed vessel was studied. • Effects of mist parameter on heat transfer process and vapor pressure were studied. This numerical study focused on the heat transfer process between the ultrafine water mist and explosion flame, and the suppression mechanism of ultrafine water mist and the effect of mist parameter on methane explosion. Hence, a three-dimensional numerical model for methane explosion suppression by ultrafine water mist was established. Large eddy simulation and partially premixed combustion models were used to determine the explosion flow field characteristics and methane explosion process, respectively. The Euler-Lagrange equation was used to solve the continuous and discrete phases, and the coupling calculation was realized by alternately solving these two phase models. In addition, the validity of the numerical model and calculation method was verified by the experimental results. Mist vaporization, heat transfer between the gas and liquid phases, and influencing factors (including the mist diameter (d), mist velocity (v), and mist concentration (Q Mist)) were analyzed quantitatively. The results indicate that heat exchange mainly occurs in the reaction zone, and the heat exchange rate can be affected by the mist parameters, which further affects the temperature inside the vessel. Moreover, the vapor pressure generated from mist vaporization is an important component of the explosion pressure in the closed vessel, and it is comprehensively affected by the mist vaporization rate and temperature. Simultaneously, the mist parameters are also the key influencing factors for the above process. [ABSTRACT FROM AUTHOR]