Numerical modelling of the discharge behaviour of particles from a gas vessel

Particle-laden gas flows occur in a wide variety of process technologies. It is therefore a common safety scenario to understand how many particles will escape in the event of a leak or emergency pressure relief. Therefore, a vessel filled with gas and homogeneously dispersed solid particles was considered. The aim was to derive a model to describe the discharge of arbitrary spherical particles. For this purpose, multiple numerical simulations were performed with ANSYS CFX & COPY;. A cylindrical vessel with a volume of 2 m3, a 25 mm opening and a length to diameter ratio of 2 was considered. The system was considered adiabatic, isentropic, compressible, and subcritical with an ideal gas. The velocity field was described with a one-way Euler-Lagrange method. The particle density, particle size, the gas in the vessel, as well as the initial temperature and pressure in the vessel were varied. Based on a dimensional analysis a model was developed to estimate the discharged mass of par-ticles. This model achieves a small mean absolute deviation from the simulation data of-0.03%. The prediction model is thus able to correctly represent all variables varied without having to carry out single complex nu-merical simulations. The model is the first model to derive the discharge behaviour of particles from pressure vessels.