Известия Томского политехнического университета: Инжиниринг георесурсов (Nov 2017)
Features of detonation wave dynamics in bubbly liquid on the border "hydroglyceric solution - oil"
Abstract
Relevance. Liquid with bubbles of a combustible mixture of gases (water with bubbles of explosive gas or a mixture of hydrocarbons with oxygen) is an explosive in which a detonation soliton with an amplitude up to 100 atm can appear when a pressure pulse of the order of 10-20 atm is applied. The specific gravity of this explosive is six orders of magnitude or more lower than that of conventional solid, liquid, and gaseous explosives. Such low-calorie explosives are an effective means for amplifying and maintaining wave signals, as well as for short-term pressure increase in local zones. In addition, in flammable liquids containing veils with vapor-air bubbles, sudden shocks during transportation can contribute to the formation of detonation solitons leading to emergency situations. The study of detonation waves in bubble liquids is related to the questions of the explosion safety of such systems. Therefore, it is necessary to study the critical parameters (initial wave amplitude, volume content and dispersity of gas bubbles) at which detonation initiation can occur. The aim of the research is to study the wave motion in inhomogeneous bubbly fluid, where the inhomogeneity is caused by the presence of a boundary between different liquids, as well as different bulk contents of bubbles. The object of the research is bubble liquids containing an explosive gas inside the bubbles. The research method is based on numerical solutions of a system of partial differential equations. The results of the study made it possible to draw conclusions about the features of the dynamics of detonation waves in a bubble liquid, in the presence of a boundary between liquids with differing acoustic properties, and to give recommendations when developing requirements for explosion safety in the transport of combustible hydrocarbons. These zones differ in acoustic properties. In addition, it is believed that these fluids contain explosive vesicles. When a pressure wave of the «step» type passes through the boundary between the zones, because of the difference in the acoustic impedances, the amplitude of the wave increases and a detonation wave can be initiated. If the volume content of bubbles is the same in both zones, then the source of the explosion can not initiate a detonation wave in the first zone due to its compression by a wave of the «step» type. In order for the detonation wave to propagate in the first zone, the volume content in the first zone should be greater than a certain critical value, depending on the amplitude of the initial wave and the gas volume content in the first and second zones.
