Modeling and simulation of supersonic nozzle gas jet laden with polydisperse fire suppressant particles injected from a bypass injector

Dry powder fire extinguishing techniques are widely used due to the environmental friendliness and high efficiency. An Eulerian-Lagrangian interphase coupled modeling is performed for 2D axisymmetric nozzle supersonic gas jets laden with polydisperse fire suppressant particles complying with a Rosin-Rammler distribution injected from a bypass injector. A corrected drag model is developed applicable for very large ranges of particle Reynolds and Mach numbers. A parametric study on performance indexes of jet determining the fire extinguishment efficiency indicates that an increase in injected particle velocity vp,inj, mean diameter dp,m or spread parameter ns, or decrease in mass flow rate qm,p usually causes a monotonous increase of particle streamwise average velocity vp,a, decrease of velocity inhomogeneity Ovp and dispersion 7,p. However, the monotonicity of parametric dependency is probably violated under extreme conditions. It is exemplified by the vp,a, Ovp or 7,p at very large vp,inj, or the 7,p at extremely large ns.