Euler-Lagrange Simulation of Fine Particle Discharge Rate under Accelerated Air Ventilation Circumstances

Abstract

Particle discharge rate R_out is simulated with Euler-Lagrange approach under accelerated air ventilation circumstances. Two factors of Stokes number St and acceleration are taken into account to investigate their influences on R_out. The particle mass flow rate q_m as an important parameter is used to evaluate the essential of the R_out. St is rescaled by changing particle diameter d_p. Consequently, the tendency of R_out is clarified under accelerated air ventilation circumstances. In the simulation, the unsteadiness of the fluid velocity field produces the unsteady forces, which include pressure gradient force f_PG and virtual mass force f_VM. Unsteady forces provide a time delay to particle movement and reduce R_out. Moreover, smaller St (St=0.001 and 0.1) increases the fine R_out, and larger St (St=1.2 and 5.0) is adverse. In the case of St=0.1, the R_out are fundamentally identical regardless of the accelerations. Nevertheless, in the case of St=1.2, the increase of the acceleration of the air ventilation circumstances reduce the R_out .