Pressure fluctuation analysis of softness abrasive flow based on Hilbert Huang transform in finishing flow channel
                                            JI Shi ming1, LI Jun1,2, TAN Da peng1*
(1.Key Laboratory of E&M., Ministry of Education & Zhejiang Province, Zhejiang University of Technology, Hangzhou 310014, China;2.School of Information Science and Engineering, Hangzhou Normal University, Hangzhou 311121, China)

Abstract: Aiming at the processing efficiency and polishing uniformity of the soft abrasive flow machining method, a pressure fluctuation monitoring method for constrained flow channel based on HHT was proposed. By using Hilbert Huang transform time frequency analysis method, the characteristics of pressure pulsation of soft abrasive flow in a flow channel were investigated. The internal relations between turbulent development and pressure fluctuation signals in the constrained channel were established. The turbulence in the channel was controlled by monitoring the pressure fluctuation signal. An experimental platform of pressure pulsation measurement and control was set up, and the on line control experiment of abrasive flow was carried out for comparision. The results indicate that the spectrum information of pressure fluctuation signal in the polishing flow channel of the soft abrasive flow obtained by using the HHT transform method, can fully reflect the frequency and amplitude information of the abrasive flow velocity at channel entrance, by monitoring the pressure fluctuation signal can achieve turbulence control. The method can not only improve the efficiency and uniformity of the soft abrasive flow machining, but also provide the possibility for the soft abrasive flow machining to achieve directional controllable polishing.

Key words: softness abrasive flow; Hilbert Huang transform (HHT); pressure fluctuation; turbulent intensity