Influence of smoke density on the parameters of the acoustic device of the rescuer's equipment

Alexander Levterow

National University of Civil Defenсe of Ukraine

http://orcid.org/0000-0001-5926-7146

Yevhenii Statyvka

National University of Civil Defenсe of Ukraine

http://orcid.org/0000-0003-1536-2031

DOI: https://doi.org/10.52363/2524-0226-2023-37-7

Keywords: acoustic device, sensor, acoustic resistance, reflection coefficient, visual control

Аnnotation

Experimentally determined correction values of the distance to the obstacle depending on the acoustic impedance of the environment for the acoustic device of the rescuer's equipment. The measurement results were obtained using the developed experimental setup, which took into account, in real time, changes in acoustic impedance and temperature of the environment using a two-channel temperature meter and an optical penetration sensor of the environment. The temperature of the environment (in the confined space) varied from 20 °C to 60 °C, and the optical penetration index from 0 to 100 %, where 100 % corresponds to complete optical opacity of the environment. Dependencies of the propagation of acoustic waves upon changing the optical permeability of the medium and temperature were obtained. The correction value for the distance to the obstacle calculated by the acoustic device at a distance of 1000 mm was (+0,013 m). The relative error during the measurements did not exceed 2 %. It was found that when the wave impedance increases, the indicators of the distance to the obstacle decrease, so the corrective dependence has a positive value. The obtained results make it possible to increase the reliability of the readings of the acoustic device as an additional equipment of the rescuer. The data obtained as a result of the experiment make it possible to display the shape of the obstacle in more detail. Approximating polynomials of the reflection coefficient of acoustic waves depending on the volume content of inclusions at angles of incidence from 0 °С to 30 °С have been determined. The use of the obtained polynomials allows to increase the speed of the program code of the control microcontroller of the acoustic device. The obtained dependencies are taken into account in the calculation algorithm of the program code of the microcontroller of the acoustic device for determining the shape and distance to the obstacle, which makes it possible to increase the efficiency of the rescuer's orientation in conditions of unsatisfactory visual control during emergency rescue operations.

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