分段螺旋式甘草茎秆揉切装置设计与试验

针对全混合日粮饲草料揉切需求，该研究设计了一种分段螺旋式甘草茎秆揉切装置，对分段螺旋叶片的主体结构和搅龙结构参数进行设计，建立了刃口曲线方程，分析了装置揉切机理，并试制了分段螺旋式甘草茎秆揉切装置试验台。以搅龙转速、加工时间、填充系数、刀片与底壳间隙为因素，以粒度、破节率、单位质量能耗为指标，开展四因素三水平Box-Behnken试验，对试验结果进行方差分析和二次回归拟合，得出各因素对粒度影响显著性由大到小为加工时间、搅龙转速、填充系数、刀片与底壳间隙；对破节率的影响显著性由大到小为加工时间、填充系数、搅龙转速、刀片与底壳间隙；对单位质量能耗的影响显著性由大到小为填充系数、加工时间、搅龙转速、刀片与底壳间隙。对交互影响因素进行响应曲面分析并进行参数优化验证试验，结果表明：当搅龙转速为25 r/min、加工时间为12 min、填充系数为0.46、刀片与底壳间隙为15 mm时，甘草茎秆的揉切粉碎粒度为11.76 mm，破节率为83.27%，此时单位质量能耗为9 959.82 J/kg，试验值与模型理论值误差不超过7%，参数优化模型合理，满足作业要求。研究结果可为全混合日粮搅拌机的研发提供理论依据。

Design and experiments of segmented helical kneading and cutting device for licorice straw

Kneading and cutting the licorice stalk for the whole total mixed ration can be used to effectively improve the quality of beef and mutton products. In this study, a segmented helical device was introduced to knead and cut the licorice stalk. The segmented helical auger was placed horizontally in the material box, and rotated in a clockwise to knead and chop the licorice stalk. Meanwhile, it can be transported in the axial direction to make the material accumulate in the middle and fall back, thereby to achieve efficient knead and cut of the licorice stalk repeatedly. The structure style, blade edge curve, and auger structure parameters were designed to reduce the axial conveying speed, while improve material cutting probability. A theoretical analysis and a developed test bench were carried out in the cutting and kneading process of a licorice stalk in the device. A four factors and three levels Box-Behnken test was performed, where the factors included the rotation speed of the segmented helical auger, processing time, fill-factor, clearance between blade and bottom case, while, the particle size, breaking rate, and the energy consumption of unit mass as indexes. The test data was analyzed by variance analysis and quadratic regression fitting. The significant influence of single factors on particle size was ranked in the order from high to low: the processing time, the rotation speed of segmented helical auger, fill-factor, clearance between blade and bottom case. The results showed that the influence factors on the breaking rate were in the order from high to low: processing time, fill-factor, rotation speed of segmented helical auger, clearance between blade and bottom case. The significant influence on the energy consumption of unit mass was in the following order from high to low: fill-factor, processing time, rotation speed of segmented helical auger, clearance between blade and bottom case. Meanwhile, the analysis of response surface showed that the grain size increased as the fill-factor increased. The particle size first decreased, and then increased with the rotation speed increased. The grain size decreased as the process time increased. When the processing time was at a low level, the grain size increased with the increase of the fill-factor. While the process time was at a high level, the grain size decreased with the increase of the fill-factor. The breaking rate increased with the increase of machining time and rotation speed, and decreased with the increase of clearance and fill-factor between the blade and the bottom case. The energy consumption of unit mass increased with the increase of the rotation speed and the processing time. However, when the rotation speed was at a low level, the energy consumption of unit mass decreased first and then increased as the fill-factor increased. When the rotation speed was at a high level, the energy consumption of unit mass decreased with the increase of the fill-factor. When the clearance between the blade and the bottom case increased gradually and the processing time was at a lower level, the energy consumption of unit mass increased, while decreased when the processing time was at a higher level. At the same time, these parameters were optimized and verified through response surface technologies. The experimental results showed that when the rotation speed, processing time, the fill-factor, and the clearance between blade and bottom case were 25 r/min, 12 min, 0.46, and 15 mm, respectively, the particle size and the breaking rate of the licorice stalk were 11.76 mm, 83.27%, respectively. Currently, the energy consumption of unit mass was 9959.82 J/kg, the error between the experimental value and the theoretical value was not more than 7%, indicating in reasonable agreement with the requirements of crushing operation. This finding can provide a theoretical basis for the research and development of TMR mixer.