Assessment of the Parameters of a Shock Wave on the Wall of an Explosion Cavity with the Refraction of a Detonation Wave of Emulsion Explosives

Pavel Igorevich Afanasev,Khairullo Faizullaevich Makhmudov

doi:10.3390/app11093976

Pavel Igorevich Afanasev, Khairullo Faizullaevich Makhmudov

Open Access

https://doi.org/10.3390/app11093976

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Journal: Applied sciences	Publication Date: Apr 27, 2021
Citations: 5	License type: CC BY 4.0

Affiliation: Saint Petersburg Mining University

Abstract

At present, studying the parameters of shock waves at pressures up to 20 GPa entails a number of practical difficulties. In order to describe the propagation of shock waves, their initial parameters on the wall of the explosion cavity need to be known. With the determination of initial parameters, pressures in the near zone of the explosion can be calculated, and the choice of explosives can be substantiated. Therefore, developing a method for estimating shock wave parameters on an explosion cavity wall during the refraction of a detonation wave is an important problem in blast mining. This article proposes a method based on the theory of breakdown of an arbitrary discontinuity (the Riemann problem) to determine the shock wave parameters on the wall of the explosion cavity. Two possible variants of detonation wave refraction on the explosion cavity wall are described. This manuscript compares the parameters on the explosion cavity wall when using emulsion explosives with those obtained using cheap granular ANFO explosives. The detonative decomposition of emulsion explosives is also considered, and an equation of state for gaseous explosion products is proposed, which enables the estimation of detonation parameters while accounting for the incompressible volume of molecules (covolume) at the Chapman–Jouguet point.

Highlights

Mining works currently use emulsion explosives, which are safe to manufacture, transport, store and employ for borehole charging [1,2,3,4,5], because they are devoid of explosive initiators such as trotyl, hexogen and other high-brisance explosives
The calculated parameters of shock waves at the boundary of the explosion cavity were compared with experimental data from a previous study [21]
Experimental data were obtained for trotyl as an explosive (Table 1) in different types of rocks (Table 2)

Summary

Introduction

Mining works currently use emulsion explosives, which are safe to manufacture, transport, store and employ for borehole charging [1,2,3,4,5], because they are devoid of explosive initiators such as trotyl, hexogen and other high-brisance explosives. The emulsion composition of the oil-in-water type, according to its physical properties and chemical composition, is characteristic of slurry explosives, since they contain a structuring agent and thickener, and the combustible component of the emulsion matrix is fuel in a solution of water and an oxidizer. The stability of the properties of such an emulsion is based on the selection of the required emulsifier. Another component of the water-in-oil type is called emulite, which is an emulsion of a highly concentrated water solution of oxidizer salts (up to 80 percent of dissolved ammonium nitrate salts) in the fuel phase. Water-in-oil emulsions have a higher resistance to water, as the smallest droplets of the oxidizing solution are inside a thin waterproof film of the fuel phase

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