| 内容提要: |
The pressure drop characteristic is the main basis for distinguishing the flow state of the particles in the pneumatic conveying. However, the general pressure fluctuation signal mainly reflects the overall state of the pipeline, so it is difficult to analyze the local flow information in these pressure information.
To solve this problem, a four-electrode electrostatic sensor with local electrostatic sensibility was used to obtain different local electrostatic signals of pipe section in three solid mass flow rate (80kg/h, 100kg/h, 120kg/h). Empirical mode decomposition (EMD) and Hurst exponent are adopted to extract the detail scale signals that representing the random movement of particles. Hurst exponent is less than 0.5, representing the random movement of particles, while the Hurst exponent is greater than 0.5, representing the stability of macro motion and reflected the effect of air flow and aggregation. Through the analysis of all the electrostatic signals, the IMF which Hurst exponent is less than 0.5 mainly focused on imf1~imf6.
By this method, the local flow characteristics of the corresponding flow field can be clearly demonstrated when the solid mass flow rates are 80kg/h, 100kg/h and 120kg/h, respectively. It has important theoretical and practical significance for further research on the stability of pneumatic conveying. |