The Research Of Winnowing Characteristics On Tobacco Cutting And Rebaking In The DPM Model

Tobacco leaf threshing and redrying is an important process that affects the quality of cigarettes,and the leaf air separation is one of the representative processes during the production of cigarette.Therefore,the research of multiple complex two-phase flow fields in the process of tobacco leaf splitting and the conversion of different proportions of tobacco leaves that affect the wind splitting effect can improve the common technology of leaf splitting during the tobacco leaf threshing and redrying process,ensuring the Quality stability of pure tobacco leaves during cigarette production.In view of the current problem that the wind separation process parameters of tobacco leaf rely on experience and other issues,this topic realizes the "white box" process of the complex "black box" inside the wind extension,Thus forming a scientific theory and basis to guide production.Firstly,the article discussed the basic theory of tobacco fluid mechanics and the gas-soild flow,establishes the trajectory equation of the tobacco leaf separation in the air chamber,and the key research has established a mathematical model for the conversion of equivalent spherical particles of tobacco leaves,and verified the rationality of the numerical simulation technology.Scondly,the article simplifies the structure of the Horizontal wind separation machine.Fluent software was used to perform numerical simulation of the gas phase at three different wind speeds on the wind flow field in the wind separation machine.The simulation results show that the gas velocity is larger at the blade outlet and the material outlet,but the pressure is smaller and a negative pressure is formed.Thirdly,based on gas-solid phase flow simulation and simulation technology,using tobacco leaf image recognition technology,the equivalent spherical particle diameters of three types of tobacco leaves: pure tobacco leaf?leaf containing stem?pure tobacco stem were determined through experiments,and the gas-solid phase flow was simulated and analyzed.The velocity field and pressure field of the first time realized the "black box" to "white box" of the tobacco leaf wind separation process.The simulation results show that the three types of tobacco leaves are layered in the wind split field,and a large number of vortices appear on the wind splitter and the middle box,and the speed varies from 1.97 m/s to 3.15 m/s,which is in line with Similarly,a negative pressure is generated at the blade outlet and the material outlet,and the maximum negative pressure is-19 Pa.Finally,In order to explore the influence of the three types of tobacco leaf ratio on the wind distribution under different experimental conditions and obtain the best working conditions,the turbulence changes and particle movement trajectories of the tobacco leaves in the wind distribution room were analyzed.And according to the index of the wind separation effect of the tobacco leaf threshing and redrying plant,that is,the wind separation efficiency requirement is greater than 80%,and the pure tobacco leaf rate is greater than 50%,the study established a wind separation effect evaluation model.The results show that the turbulence changes are mainly concentrated in the flow field in the upper area of the wind separation machine,and an obvious annular turbulent flow is formed in the middle area of the wind separation machine,with a maximum velocity of 8.29 m/s;Affected by the overlapping space,the residence time of some pure tobacco leaves in the wind shunt field is too long for 4.63 s,and the movement trajectory shows a circular movement trend in the middle box;Through simulation and experiment analysis of the wind separation efficiency and film output rate of pure tobacco leaves under different working conditions,the best working condition for improving the wind separation effect was obtained,that is,the frame bar opening was 2.8° and the roller speed was 50r/s.The efficiency of wind division is 85.94%,and the pure tobacco leaves rate is 87.15%,which verifies the feasibility of using tobacco leaf equivalent spherical particles for numerical simulation.