Based on the engineering application, the angle range of rectifying airflow unit attaching diffusion tank is from 2.5° to 7.5°. In the range of average inlet velocity of 25.0 m/s to 55.0 m/s of diffusion tan...Based on the engineering application, the angle range of rectifying airflow unit attaching diffusion tank is from 2.5° to 7.5°. In the range of average inlet velocity of 25.0 m/s to 55.0 m/s of diffusion tank, numerical simulations of diffusion tank were done. The results of numerical simulations of diffusion tank are shown as follows： ③ In cases of the inlet velocity range from 25.0 m/s to 55.0 m/s, and the angle range of rectifying airflow unit from 2.5° to 7.5°, the average value of pressure losses decreases to the minimum when the angle is 4.5°.② In cases of the inlet velocity of 35.0 m/s, the pressure loss of diffusion tank decreases to the minimum when the angle of rectifying airflow unit is 5.5°. ③ As far as there are different angles of rectifying airflow unit, pressure loss increases gradually along with the addition of inlet velocity.展开更多
In order to study the movement characteristics and separation mechanism of rice and its impurities under the action of airflow,and lower the impurity rate in the cleaning operation process,rice and its impurities were...In order to study the movement characteristics and separation mechanism of rice and its impurities under the action of airflow,and lower the impurity rate in the cleaning operation process,rice and its impurities were modeled based on the“overlapping multi-sphere clump method”,the DEM-CFD coupling method was used to simulate rice cleaning process under different airflow velocity and airflow inclined angle,and combined with aerodynamics,the motion state and separation behavior of rice and its impurities in the flow field.The results showed that under horizontal airflow conditions,the average impurity rate of rice was the lowest when the airflow velocity was 9 m/s.When the flow velocity remains unchanged and the airflow inclined angle was set at 10°,the average impurity rate decreased,while the entrainment loss rate increased.The airflow velocity was negatively correlated with the impurity rate and positively correlated with the entrainment loss rate,while the airflow inclined angle was negatively correlated with the impurity rate and positively correlated with the entrainment loss rate.By designing and setting up an experimental device,an experiment was carried out with airflow velocity and airflow inclined angle as the factors,and the experimental results were consistent with the simulation results,indicating that it was reliable to study the physical behavior of rice-straw separation in the airflow field by using the DEM-CFD coupling method.展开更多
基金Supported by the National Natural Science Foundation of China （51074073） the Project of Hunan Provincial Science ＆ Technology Department （2010XK6066） the Project of Scientific Research Fund of Hunan Provincial Education Department （10C0675）
文摘Based on the engineering application, the angle range of rectifying airflow unit attaching diffusion tank is from 2.5° to 7.5°. In the range of average inlet velocity of 25.0 m/s to 55.0 m/s of diffusion tank, numerical simulations of diffusion tank were done. The results of numerical simulations of diffusion tank are shown as follows： ③ In cases of the inlet velocity range from 25.0 m/s to 55.0 m/s, and the angle range of rectifying airflow unit from 2.5° to 7.5°, the average value of pressure losses decreases to the minimum when the angle is 4.5°.② In cases of the inlet velocity of 35.0 m/s, the pressure loss of diffusion tank decreases to the minimum when the angle of rectifying airflow unit is 5.5°. ③ As far as there are different angles of rectifying airflow unit, pressure loss increases gradually along with the addition of inlet velocity.
基金The authors acknowledge that this work was financially supported by the National Natural Science Foundation of China(Grant No.51775258).
文摘In order to study the movement characteristics and separation mechanism of rice and its impurities under the action of airflow,and lower the impurity rate in the cleaning operation process,rice and its impurities were modeled based on the“overlapping multi-sphere clump method”,the DEM-CFD coupling method was used to simulate rice cleaning process under different airflow velocity and airflow inclined angle,and combined with aerodynamics,the motion state and separation behavior of rice and its impurities in the flow field.The results showed that under horizontal airflow conditions,the average impurity rate of rice was the lowest when the airflow velocity was 9 m/s.When the flow velocity remains unchanged and the airflow inclined angle was set at 10°,the average impurity rate decreased,while the entrainment loss rate increased.The airflow velocity was negatively correlated with the impurity rate and positively correlated with the entrainment loss rate,while the airflow inclined angle was negatively correlated with the impurity rate and positively correlated with the entrainment loss rate.By designing and setting up an experimental device,an experiment was carried out with airflow velocity and airflow inclined angle as the factors,and the experimental results were consistent with the simulation results,indicating that it was reliable to study the physical behavior of rice-straw separation in the airflow field by using the DEM-CFD coupling method.
