Method of detecting bubbles in a pipeline by vibration excitation

The transportation of liquids through pipelines has extensive applications in the industrial sector. However, due to factors such as localized negative pressure or discontinuities in fluid flow, the formation of bubbles within the pipeline is a common occurrence. Developing an effective method for detecting these internal bubbles is of significant practical importance. Pipelines containing bubbles can be conceptualized as multiphase flow systems, where the frequency domain characteristics of the system vary with changes in bubble volume. Based on this principle, this paper proposes a method for identifying bubbles within pipelines by analyzing the frequency domain features of mechanical vibration waves. To validate the efficacy of this method, a testing apparatus was constructed to use pressure sensors to detect the pressure signals at the inlet and outlet of a pipeline. By analyzing the amplitude ratio and phase difference of the two signals, the presence of bubbles within the pipeline can be determined. The results demonstrate that this method is effective in detecting bubbles within the pipeline.