针对山区丘陵平贝母收获费时费工、机械化水平不高等现状,设计了一种与手扶拖拉机相配套的平贝母药材收获机。该机主要由刮土机构、挖掘铲、振动筛、筛下分贝土机构、装袋装置等组成。利用解析作图法对振动筛串联四杆机构进行分析,确定...针对山区丘陵平贝母收获费时费工、机械化水平不高等现状,设计了一种与手扶拖拉机相配套的平贝母药材收获机。该机主要由刮土机构、挖掘铲、振动筛、筛下分贝土机构、装袋装置等组成。利用解析作图法对振动筛串联四杆机构进行分析,确定平贝母和土壤混合物能顺利通过筛面的驱动轴转速范围240~535 r/min;对反向螺旋叶片上的平贝母进行受力分析得出减小平贝母碰撞破损的筛下分土机构螺旋叶片转速小于4 m/s;平贝母收获试验样机田间试验表明：该机作业顺畅、性能稳定,匹配动力为13.2 k W的手扶拖拉机,平贝母损失率小于4.9%、损伤率小于4.1%,满足行业标准规定,筛后贝土输送螺旋能顺畅地将贝土分至畦面两侧。该研究为产品级平贝母药材收获机的研制提供技术参考。展开更多
Low-head hydraulic turbines are the subjects to individual approach of design. This comes from the fact that hydrological conditions are not of a standard character. Therefore, the design method of the hydraulic turbi...Low-head hydraulic turbines are the subjects to individual approach of design. This comes from the fact that hydrological conditions are not of a standard character. Therefore, the design method of the hydraulic turbine stage has a great importance for those who may be interested in such an investment. As a first task in a design procedure the guide vane is considered. The proposed method is based on the solution of the inverse problem within the flame of 2D model. By the inverse problem authors mean a design of the blade shapes for given flow conditions. In the paper analytical solution for the simple cylindrical shape of a guide vane is presented. For the more realistic cases numerical solutions according to the axis-symmetrical model of the flow are also presented. The influence of such parameters as the inclination of trailing edge, the blockage factor due to blade thickness, the influence of loss due to dissipation are shown for the chosen simple geometrical example.展开更多
文摘针对山区丘陵平贝母收获费时费工、机械化水平不高等现状,设计了一种与手扶拖拉机相配套的平贝母药材收获机。该机主要由刮土机构、挖掘铲、振动筛、筛下分贝土机构、装袋装置等组成。利用解析作图法对振动筛串联四杆机构进行分析,确定平贝母和土壤混合物能顺利通过筛面的驱动轴转速范围240~535 r/min;对反向螺旋叶片上的平贝母进行受力分析得出减小平贝母碰撞破损的筛下分土机构螺旋叶片转速小于4 m/s;平贝母收获试验样机田间试验表明：该机作业顺畅、性能稳定,匹配动力为13.2 k W的手扶拖拉机,平贝母损失率小于4.9%、损伤率小于4.1%,满足行业标准规定,筛后贝土输送螺旋能顺畅地将贝土分至畦面两侧。该研究为产品级平贝母药材收获机的研制提供技术参考。
文摘Low-head hydraulic turbines are the subjects to individual approach of design. This comes from the fact that hydrological conditions are not of a standard character. Therefore, the design method of the hydraulic turbine stage has a great importance for those who may be interested in such an investment. As a first task in a design procedure the guide vane is considered. The proposed method is based on the solution of the inverse problem within the flame of 2D model. By the inverse problem authors mean a design of the blade shapes for given flow conditions. In the paper analytical solution for the simple cylindrical shape of a guide vane is presented. For the more realistic cases numerical solutions according to the axis-symmetrical model of the flow are also presented. The influence of such parameters as the inclination of trailing edge, the blockage factor due to blade thickness, the influence of loss due to dissipation are shown for the chosen simple geometrical example.
