Research Of Distribution And Dynamic Characteristic Of Particle Group In Structural Flow Passage

Research of distribution and dynamic characteristic of particle group in structural flow passage is of important guiding significance to softness abrasive flow machining (SAFM), when the particle group motion rule is fully understand, it is possible to discuss further on control methods of abrasive flow pattern, to meet the demands of different machining circumstances. Aiming at the problems of softness abrasive flow (SAF), such as different interphase acting force in different particle concentration, inconvenient observing particle group motion, a kind of research method based on particle group distribution was put forward; distribution and dynamic characteristic of particle group were discussed deeply, and the feasibility and effectiveness of SAFM method can be reaffirmed fundamentally, the main work is as follows:1. Start with liquid-solid two-phase flow and turbulence model, this paper first analysis the single particle dynamics model, then comprehensive analysis the motion and stress between two-phase in a low concentration and in a high concentration, as well as the turbulent numerical simulation method, suitable for low concentration and high concentration of liquid-solid two-phase SAF physical model is described.2. Aiming at SAF in different concentration, a two-phase fluid dynamic basic model was built based on mixture model method, and with realizable k ?εturbulence model the numerical simulation of SAFM in the flow passage which has V-shaped texture and semicircular cross-section was carried out, the SAF's parameters (e.g. velocity field and distribution of particle group, etc.) in the flow passage which has V-shaped texture and semicircular cross-section and the near wall area were obtained.3. The particle motion and turbulent diffusion model of SAF which is in a low concentration were studied. Using discrete phase random walk model and speed control way, the simulation of particle group motion in the flow passage which has V-shaped texture and rectangular section in SAFM processing was carried out. The movement characteristics and kinetics characteristics were obtained, and it is proved that the flow field in the flow passage has reached turbulent state.4. Build the particle group movement observation device Based on particle image velocimetry (PIV) system to observe the movement of particle group. The motion characteristics and vorticity characteristics of particle group were obtained by cross-correlation technique matching image particles method, which proved the accuracy of simulation results; according to observation experiment, design the flow passage which has V-shaped texture and rectangular section, and prove the accuracy of observation experiments based on practical processing experiment.5. The fractal dimension of particle group in flow passage is calculated based on fractal theory and image processing technology in the box counting dimension method. Results show that distribution of particle group in flow passage has the fractal characteristics, and flow field in the flow passage has reached turbulent state, so the feasibility and effectiveness of SAFM method can be reaffirmed fundamentally.There are certain theoretical guidance and technical reference value for promoting the development of structured surface polishing and enriching the theory of SAFM.