| In order to improve the extrusion quality of peanut protein in single screw extruder, based on the crushing effect of tensile stress, the traditional single screw extruder was used as a reference, the finite element software CFX was used to calculate the movement of peanut protein in the flow field, the characteristics of the new mixing single screw extruder was analyzed through the pressure field, velocity streamline field and strain rate field, the design principle with tensile rheological theory was verified, and the process parameters of the new extruder were optimized by response surface methodology. The results showed that the diversion effect of the mixing element in the new extruder made the pressure drop along the extrusion direction, and the material flows back, resulting in reduced pressure building performance, thereby prolonging the residence time, and the local high pressure generated by the reflux effect here was also conducive to calendering, the material could experience both circumferential stretching and radial stretching when flowing through the parabolic surface, and the dispersion mixing effect was better. After simulation calculation, it was found that the average strain rate of the new extruder was 165% higher than that of the traditional extruder, which made the quality of extrusion product better. The order of influence of each factor on the average strain rate of peanut protein was screw speed, convergence ratio, segmentation prism thickness, and the optimal process parameters of the new single screw extruder were screw speed 128 r/min, convergence ratio 6.6, and segmentation prism thickness 3.1 mm. Under the optimal conditions, the theoretical average strain rate of peanut protein was 50.945 s-1. In conclusion, the extrusion quality of peanut protein is effectively improved due to the formation of tensile flow field in the new mixing single screw extruder. |
