A Study On Acoustic Leakage Detection Technology For Power Plant Boiler Tubes

As acoustic leakage detection technology for power plant boiler tubes can detect small leakages early in boiler tubes before they become catastrophic leakages and reduce economic loss resulted from disarranged stopping of boilers, many research institutes have begun to pay attention to it. On basis of the existing research achievement this paper does more deeply study on this technology, and it is presented as follows:1. The cause of leakages in power plant boiler tubes is analyzed.2. The aero acoustic principle of jet noise resulted from leakages is analyzed, the acoustic characteristics of jet noise, such as the jet exit velocity, the overall sound pressure level and the noise spectra characteristics are studied, on which acoustic model for leakage jet noise in power plant boiler tubes is built. 3. Some main components of background noise in normal running process and their acoustic characteristics are considered.4. Some primary attenuation factors that affect the traveling of acoustic wave are taken into account.5. The leakage noise signal and the background noise signal obtained from the sensors installed in boilers are processed. Finite Impulse Response (FIR) digital filter and spectral analysis approaches, including Periodogram method and Burg method, are adopted to differentiate leakage noise from background noise.6. The hardware devices of acoustic leakage detection system for boiler tubes are developed and online detection application software is programmed, which achieve the following function: detecting the occurrence and development of the leakages, recording historical data, estimating the leakage location, displaying the leakage noise spectrum, tracing on the trend of the leakages...