Research on Drag Reduction Performance of Sliding Plate of Rice Direct Seeding Machine Based on Non Smooth Structure of Loach Surface

Sliding plate was the key soil-engaging component of rice direct seeding and planting machinery. It has the problems of large sliding resistance and serious soil adhesion. which has a serious negative impact on the operation efficiency and quality of rice planting machinery. Reducing the soil adhesion and resistance between sliding plate and soil can significantly improve the operation effect of the whole machine and reduce power consumption. Loach moves freely and flexibly in the mud and has highly efficient lubrication and drag reduction effects. The movement state of sliding plate was similar to that of loach, as well as the working environment and conditions. Therefore, the sliding plate of rice direct seeding machine was selected as the research object and the loach as the bionic prototype. The macroscopic and microscopic structure characteristics of the scales were observed, the results showed that the body surface of the loach was covered by scales, and the scales had a ridged non-smooth structure. The simulation analysis of the drag reduction performance of the non-smooth structure based on Fluent was carried out, the results show that the maximum drag reduction rate was 2.55% at the speed of 1m/s. The bionic sliding plate of rice direct-seeding machine was constructed based on the non-smooth structure of loach body surface, and its working performance was simulated and analyzed. The single factor test results show that at the speed of 1m/s, the drag reduction rate of ribbed height in the range of 3.5mm to 4.5mm was relatively high, the drag reduction rate of ribbed width in the range of 4mm-5mm was relatively high; the drag reduction rate was relatively high when the distance between ribs was in the range of 4mm5mm. The results of orthogonal test show that the order of primary and secondary factors of bionic structure parameters affecting drag reduction rate was ribbed spacing > ribbed width > ribbed height. The optimal parameter combination was ribbing height 4mm, ribbing width 4.5mm, ribbing spacing, and the optimal drag reduction rate was 4.21%. The results of this study can provide theoretical support for bionic design of soil engaging components of rice planting machinery in wet and soft paddy field.