Study on dynamic response mechanism of rice grains in friction rice mill and scale-up approach of parameter based on discrete element method

Rice milling is a key step that decides nutritional quality and economic benefits of rice in rice processing. Because of diverse requirements for the bran removal degree and rice handling capacity, rice milling effect must be accurately controlled. In this study, the milling process of rice in milling cavity was simulated through discrete element method, and simulation effectiveness was verified by experiments. Dynamic response characteristics of rice particles to different parameters were clarified. The more energy input and the larger particle volume fraction in shear zone, the higher milling degree of rice. A scale-up mathematical model involving structural and operating parameters was established for the first time. There is a linear relationship between the model and the energy loss. Experimental results showed that the model can accurately predict the milling degree of rice. This study can provide theoretical guidance for the design of rice mill or similar equipment.