Numerical Simulation for the Combustion of a Zirconium/ Potassium Perchlorate Explosive inside a Closed Vessel

Abstract

The combustion of zirconium potassium perchlorate (ZPP) in a closed vessel is modelled and validated through a numerical simulation. Because the extremely high pressure oscillation occurs in less than a millisecond, an in-house computational fluid dynamics (CFD) code is used to observe the detailed flow structures and determine the adequate burning characteristics, including the burning rate. A hybrid RANS/LES scheme with a 5 th order upwind weighted essentially non-oscillatory (WENO) is implemented to capture complex, strong shock waves in highly turbulent combustion. A two-way coupled Eulerian-Lagrangian scheme tracks the combusting ZPP granules reasonably well. Monodisperse and Rosin-Rammler assumptions are applied to the ZPP granule distribution. The monodisperse assumption reveals that the diameter of the ZPP (17 mm) achieves marginal agreement with the measurements. However, the Rosin-Rammler distribution improves the transient and dynamic combustion characteristics in that the small granules contribute to a faster burning rate and stronger shock waves. These results are more analogous to the closed vessel tests used as validation data.

Concept of Unburning Ratio and Combustion Modeling of ZPP and BKNO3 in Pyroshock‐Reduced Separation Nut

“…When the protective closure is ruptured by internal pressure, the explosive charges are also expelled to outside of the initiator, dispersing very quickly in all directions. It can also be observed in the snapshot of ZPP combustion in open space shown in Concept of Unburning Ratio and Combustion Modeling of ZPP and BKNO 3 in Pyroshock-Reduced Separation Nut [13]. Therefore, it is highly probable that some explosive charges stick to the wall.…”

“…To simulate pyrotechnic mechanical devices that are actuated by pressure, many studies have been done to model the combustion of single explosive charge such as cyclotetramethylene tetranitramine (HMX) [3][4][5][6], and zirconium potassium perchlorate (ZPP) [7][8][9][10][11][12][13]. However, for many pyrotechnics, ZPP is used as the initiating explosive and boron potassium nitrate (BKNO 3 ) is used as the main charge explosive.…”

Numerical simulation of the effect of combustion characteristics of main charges on the output shock of a typical igniter

“…Despite this, few studies have used numerical simulations to investigate the combustion characteristics of typical pyrotechnic charges in closed vessels such as aluminium/potassium perchlorate (APP), zirconium/potassium perchlorate (ZPP), boron/potassium nitrate (BPN), and carbon/potassium nitrate (CPN). Han et al [4][5] used the Eulerian-Lagrangian method to simulate the combustion process of ZPP in the cylindrical and the spherical closed. They suggest that the different pressure characteristics occur due to the combustion wave movements generated by the rapid ZPP combustion.…”

Numerical Investigation of Pyrotechnical Initiators and Their Impact in Airbag Inflator Applications: Ballistic Modeling and Functional Analysis

“…Closed bomb tests [20][21][22] are commonly used to evaluate the initiator performance and to control the production quality by measuring the pressure evolution with the help of pressure sensors. In the schematic of a closed bomb test shown in Figure 1, an initiator is actuated into a closed bomb which is a vessel with constant volume.…”

“…Instead, the granules with specific distribution had to be utilized. Han et al [20] modeled the combustion of ZPP in a closed vessel by applying the Rosin-Rammler distribution [28], considering the cumulative mass of all the granules. Based on this size distribution, Hwang et al [29] proposed a precise analytical model for pyrotechnically actuated devices by investigating the combustion characteristics of ZPP charged in a small volume chamber.…”