ANALYSIS OF THE INFLUENCE OF FILTRATION ON THE SENSITIVITY OF THE CUMULANT METHOD OF DETECTING THE ACOUSTIC SIGNALS OF LEAKAGE

An experimental study of the ratio of cumulants of acoustic signals of fluid leakage in a pipeline and interference is carried out. It is shown that the use of bandpass filtering increases the ratio of cumulants by orders of magnitude. The purpose of the article is to analyze the sensitivity of the cumulant method of detecting fluid leaks in a pipeline based on the statistical processing of the acoustic leakage signal and interference generated by the moving fluid flow. To analyze the possibilities of a cumulant leak detection method, it is necessary to have specific values of cumulants of real leakage signals and interference, which can be obtained as a result of a full-scale experiment. To generate a leakage signal, an installation is used that allows physical modeling of the leakage of liquid in the pipe in standing water. To simulate a leak in a pipe, a nozzle with copper walls and a through hole with a diameter of 1 mm was used, and a pressure of 6 atmospheres was maintained to produce leakages in the pipe. As a interference, noise generated by a moving fluid flow in the pipeline is used. The interference was recorded on the pipeline of the distribution network at a pressure of 7 atmospheres, the volume flow of the coolant averaged more than 1000 liters per hour, which ensured the flow rate of the fluid at which its motion can be considered turbulent. The results of experimental studies of acoustic signals of fluid leakage in the pipeline and interference showed that the main interference power is concentrated in the 0...5 kHz band, and the leakage signal is in the band 5...10 kHz. With the use of bandpass filtering, the ratio of the mean square deviation of the leakage signals and interference increased by more than an order of magnitude for the frequency bands 5...10 kHz and 10...15 kHz, as compared with the absence of filtering. In this case, the ratio of the absolute values of the cumulants of the leakage signal and the interference is much greater than the ratio of the variances, and the ratio of cumulants increases substantially with increasing order. This confirms the sensitivity of high-order cumulants to the presence of a leak.