| Title |
Experimental Study on Leak and Wall-thinning Detection by Acoustic Emission and Vibration Features of District Heating Pipe |
| Authors |
Hyon Wook Ji ; Heela Jang ; Inju Hwang ; Hongcheol Lee |
| DOI |
https://doi.org/10.6110/KJACR.2022.34.8.380 |
| Keywords |
가속도계; 음향방출; 이상상태 진단; 지역난방관로; 이중보온관 Accelerometer; Acoustic emission; Diagnosis of abnormal conditions; District heating pipes; Pre-insulated pipe |
| Abstract |
This study applied acoustic emission sensors and accelerometers to monitor and evaluate the conditions in pre-insulated pipes, the district heating pipes. These measurement techniques yield high accuracy in the monitoring of the pipes. The purpose was to detect leaks, which have been relatively well studied, as well as wall-thinning in the pipes. Measurement data were acquired from the acoustic emission sensors and accelerometers in a test facility with a 60-m long pipe. Filters determined through the spectral analysis of signals, considering the state of the pipes, were then applied. The results showed that leaks were detected in the low-frequency domain, whereas wall-thinning was detected in the high-frequency domain. Fifteen features were applied to the raw data and two types of filtered data, and three features that yielded the best detection performance were identified. The results were plotted in 3D coordinates, which enabled distinguishing the normal state, leak, and wall-thinning by visual observation. |