| The circular mould granulator is one of the common biomass molding equipment on the market, which plays an important role during the extrusion process. Although great achievements have been made in the biomass molding technology and equipment manufacture in recent years in China, there are many problems are still unsolved. For example, the life of the key parts of circular mould granulator is low, the granulation process is imperfect and so on.The horizontal circular mould granulator is designed based on the practical requirements in the paper. The important design parameters of the circular mould granulator are calculated, including rotating speed of circular mould, main motor power, power of unit area and so on. The structure design of key part are designed. The 3D model of horizontal circular mould granulator is built by the SolidWorks.In this paper, according to the characteristics of the extrusion process of straw and other materials, the normal temperature extrusion process is used to this granulator. The route of particle molding is determined. The mechanical model of the die hole of circular mould in the extrusion process is calculated. The formulas of pressure and friction force on the inner wall of the die hole during the extrusion process are calculated. The D-P model in the software is usd to be the material in the extrusion process of straw. The change rule of the material in the extrusion process is simulated by software of ANSYS. It is found the maximum stress in the bottom boundary of feeding hole by the simulation the extrusion process of the material in the die hole.According to the die hole parameters (compression ratio, diameter of die hole, angle of cone hole, depth of cone hole), the test is arranged by the orthogonal table L25(56). The model of the structure is built and analysed by software ANSYS. The optimum die hole parameters that based on using the maximum equivalent stress in the extrusion process as index is got, compression ratio is 5.5:1, diameter of die hole is 12mm, angle of cone hole is 30°, depth of cone hole is 8mm. Four circular mould structure is designed based on arrangement of die hole arrangement and opening ratio, the finite element analysis of circular mould structure is carried out using ANSYS, the force exerted on the die hole during the extrusion process is applied to the finite element model. The center distance of the circular mould is 17.5mm and the opening rate is 35.43%, the die hole is an equilateral triangle arrangement, which has smaller stress and displacement of circular mould and improve the service life of the ring die.Through the static analysis and the modal analysis of spindle of the granulator by using finite element software ANSYS, the displacement and stress of the granulating machine spindle are got, it is found that the stress value is smaller than the allowable stress of the material. The first six order natural frequency and vibration mode are obtained by modal analysis, and calculate the critical speed of the spindle. The circular mould granulator would be no resonance during operating, there are some parts that can be optimized. The spindle of the granulator is established by ANSYS Parametric Design Language (APDL), an optimal design for spindle of the granulator by using the zero order optimization optimal method is performed. The optimization objective is the minimum volume. In the case of ensuring the strength of the spindle, the optimized volume is reduced by 16.1%, which provides a theoretical basis for the lightweight design of the spindle. |
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