Defining the features of amplitude and phase spectra of dangerous factors of gas medium during the ignition of materials in the premises

Abstract

This paper theoretically substantiates research into the spectral features of the dynamics of the main dangerous parameters of a gas environment when igniting materials in a laboratory chamber. Studying such spectral features is based on the calculation of the direct discrete Fourier transform for discrete measurements, equal in number, over the current intervals of observation of the hazardous examined parameter of the gas medium before and after the material is ignited. In this approach, a Fourier discrete transform makes it possible to determine the instantaneous amplitude and phase spectra for the time intervals under consideration. This makes it possible to explore the peculiarities of the distribution of amplitudes and phases of harmonic components in the spectrum of the dynamics of dangerous parameters of the gas environment before and after the ignition of materials. The results of experimental studies established that the nature of the amplitude spectrum is low-informative and not sensitive enough to fires. The main contribution to the amplitude spectrum of the dynamics of the investigated hazardous parameters of the gas environment in the chamber is made by the frequency components in the range of 0–0.2 Hz. The contribution to the amplitude spectrum of frequency components over 0.2 Hz is insignificant and decreases with increasing frequency. It is established that from the phase spectrum, the nature of the random scattering of phases for frequency components exceeding 0.2 Hz is informative. It was found that the nature of the phase spread for these frequency components in the spectrum depends on the type of ignition material. The results reported here could prove useful when devising new effective technologies for detecting fires in the premises of objects in various fields to protect against fires. This is explained by the fact that for the detection of fires in the premises, high-frequency components are important, characterized by the increase in dangerous parameters of the gas environment