Analysis Research Based On Multifractal For Flow Field Of Hydrodynamic Suspension Polishing Plate

Amorphous thin film is one of the important amorphous material, and its excellent performance make it has broad application prospects in the fields of electronic, mechanical, chemical and defense. The quality of amorphous thin film substrate has a significant impact on the performance of amorphous films. Hydrodynamic suspension polishing method is suitable for the processing of amorphous film substrate. The study of hydrodynamic suspension polishing base plate flow field is to ensure and enhance the hydrodynamic suspension polishing quality. In this paper, theoretical calculations and numerical simulation has been used to study different base plate structure, abrasive particle movement and distribution has be observed and analyzed with high-speed photography under the operating status, and bubble distribution in dynamic flow field was analyzed by the multi-fractal theory. The study includes the following sections:(1) Based on the hydrodynamic theory, hydrodynamic suspension polishing base plate mathematical model was established. Put forward three kinds of structured flow channel, including wedge-shaped, L-shaped, parabolic-shaped. Theoretical calculations and numerical simulation was used to compare their ability to generate buoyancy, and analyze the relationship between buoyancy and structural parameters. The results show that buoyancy generated by wedge-shaped and parabolic-shaped structures can lift the base plate in the polishing process, and the floating capacity of the parabolic shaped structure is a little better.(2) Studied the fractal test method of the hydrodynamic suspension polishing base plate flow field characteristics, designed and built a fractal test platform for hydrodynamic suspension polishing base plate flow field characteristics. The dynamic flow field of hydrodynamic suspension polishing was shot with high-speed photography, it was used to flow field characteristics analysis. (3) Abrasive movement and distribution in the dynamic flow field of the hydrodynamic suspension polishing was analyzed. The results show that the movement of abrasive flow in the hydrodynamic suspension polishing base plate flow field meets hydrodynamic theory, and hydrodynamic suspension polishing has a good polishing quality when its rotational speed less than50r/min.(4) Based on the fractal theory and the multi-fractal theory, Matlab software was used to extract the information of bubble distribution in hydrodynamic suspension polishing dynamic flow field, and calculate the multi-fractal spectrum. Finally, conducted a correlation analysis of the multi-fractal spectrum, the results show that:low rotational speed benefits polishing quality when it has satisfied the conditions of buoyancy.