分流对冲与多级扩容式自动集沙仪集沙盒的设计参数分析
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摘要
研究和防治农田或草地的土壤风蚀,必须掌握风蚀地表的风沙流结构,集沙仪是观测风沙流结构和获取风蚀量的关键仪器。自动集沙仪虽然可以得到实时、连续的风蚀量,但是当排沙口气流速度过大时,气流容易冲击集沙盒底部的称重传感器,影响测量数据的正确性。以分流对冲与多级扩容式自动集沙仪的风沙分离器和集沙盒为研究模型,将集沙盒简化为排沙口气流的下行空间,下行空间与风沙分离器组成连通体,再利用Gambit软件和Ansys Workbench软件的联合仿真,对不同参数的连通体的速度场进行分析,最后进行试验验证。结论表明:分流对冲与多级扩容式自动集沙仪的集沙盒设计参数的变化既不会影响风沙分离器内部流场的分布特征,也不会影响风沙在风沙分离器内部的分离,但对排沙口气流的影响较大,当集沙盒的设计参数满足L≥0.5 D1且D2≥2 D1或L≥D1且D2≥D1时,排沙口气流的部分高速气流会收缩至排沙口附近,不会冲击集沙盒下面的称重传感器,确保自动称重数据的可靠性。
To study and control soil erosion in farmland or grassland,wind-sand flow structure of wind erosion surface must be mastered,and sand sampler is a key instrument for observing the structure of wind-sand flow and obtaining the amount of wind erosion.Although the automatic sand sampler can obtain real-time and continuous wind erosion,however,when airflow velocity at the outlet is too high,the airflow will easily impact the weighing sensor at the bottom of the sandbox,affecting the accuracy of the measurement data.In this paper,the wind-sand separator and sandbox of the shunt-hedging and multi-stage expansion combined automatic sand sampler are taken as study models,the sandbox is regarded as the downlink space of the airflow at the outlet,the downlink space is connected with the wind-sand separator of the sand sampler to form a connecting body,and then using Gambit and Ansys Workbench software to analyze the downstream space of different parameters,and carried out a experimental verification.The result showed that design parameters of sandbox of the shunt-hedging and multi-stage expansion combined automatic sand sampler will neither affect the flow field in the wind-sand separator nor affect the separation of wind-sand in the wind-sand separator,but it has great influence on the airflow at the outlet,when the design parameters of the sandbox are satisfied,when L≥0.5 D1 and D2≥2 D1 or L≥D1 and D2≥D1,part of the high-speed air flow at the desilting outlet will shrink to the vicinity of the desilting outlet and will not impact the weighing sensor under the sandbox,thus ensuring the reliability of the automatic weighing data.
To study and control soil erosion in farmland or grassland,wind-sand flow structure of wind erosion surface must be mastered,and sand sampler is a key instrument for observing the structure of wind-sand flow and obtaining the amount of wind erosion.Although the automatic sand sampler can obtain real-time and continuous wind erosion,however,when airflow velocity at the outlet is too high,the airflow will easily impact the weighing sensor at the bottom of the sandbox,affecting the accuracy of the measurement data.In this paper,the wind-sand separator and sandbox of the shunt-hedging and multi-stage expansion combined automatic sand sampler are taken as study models,the sandbox is regarded as the downlink space of the airflow at the outlet,the downlink space is connected with the wind-sand separator of the sand sampler to form a connecting body,and then using Gambit and Ansys Workbench software to analyze the downstream space of different parameters,and carried out a experimental verification.The result showed that design parameters of sandbox of the shunt-hedging and multi-stage expansion combined automatic sand sampler will neither affect the flow field in the wind-sand separator nor affect the separation of wind-sand in the wind-sand separator,but it has great influence on the airflow at the outlet,when the design parameters of the sandbox are satisfied,when L≥0.5 D1 and D2≥2 D1 or L≥D1 and D2≥D1,part of the high-speed air flow at the desilting outlet will shrink to the vicinity of the desilting outlet and will not impact the weighing sensor under the sandbox,thus ensuring the reliability of the automatic weighing data.
引文
[1]宋涛.分流对冲与多级扩容组合式自动集沙仪及其内流场特性研究[D].呼和浩特:内蒙古农业大学,2016.Song Tao.Study on inner flow-field characteristics and shunt-hedging and multi-stage expansion combined automatic sand sampler[D].Hohhot:Inner Mongolia Agricultural University,2016.
[2]麻硕士,陈智.土壤风蚀测试与控制技术[M].北京:科学出版社,2010.
[3]安蕾.集沙仪集沙效率的数值模拟及其优化设计[D].兰州:兰州大学,2011.An Lei.Computational simulation of sampling efficiency and optimal design of the sand trap[D].Lanzhou:Lanzhou University,2011.
[4]宋涛,陈智,麻乾,等.分流对冲式集沙仪设计与性能试验[J].农业机械学报,2015,46(9):173-177.Song Tao,Chen Zhi,Ma Qian,et al.Design and performance experiment of shunt-hedging sand sampler[J].Transactions of the Chinese Society for Agricultural Machinery,2015,46(9):173-177.
[5]黄炎,赵满全,刘汉涛,等.基于ANSYS FLUENT对旋风分离式集沙仪内流场的分析[J].中国农机化学报,2014,35(2):310-313,329.Huang Yan,Zhao Manquan,Liu Hantao,et al.Analysis of the flow field of whirling separation sand sampler based on ANSYS FLUENT[J].Journal of Chinese Agricultural Mechanization,2014,35(2):310-313,329.
[6]宋涛,孟晓军,边炳传,等.分流对冲与多级扩容式集沙仪排气管参数优化与流场模拟[J].中国农机化学报,2018,39(8):27-32.Song Tao,Meng Xiaojun,Bian Bingchuan,et al.Flow field simulation and parameter optimization of exhaust pipe of a shunt-hedging and multi-stage expansion sand sampler[J].Journal of Chinese Agricultural Mechanization,2018,39(8):27-32.
[2]麻硕士,陈智.土壤风蚀测试与控制技术[M].北京:科学出版社,2010.
[3]安蕾.集沙仪集沙效率的数值模拟及其优化设计[D].兰州:兰州大学,2011.An Lei.Computational simulation of sampling efficiency and optimal design of the sand trap[D].Lanzhou:Lanzhou University,2011.
[4]宋涛,陈智,麻乾,等.分流对冲式集沙仪设计与性能试验[J].农业机械学报,2015,46(9):173-177.Song Tao,Chen Zhi,Ma Qian,et al.Design and performance experiment of shunt-hedging sand sampler[J].Transactions of the Chinese Society for Agricultural Machinery,2015,46(9):173-177.
[5]黄炎,赵满全,刘汉涛,等.基于ANSYS FLUENT对旋风分离式集沙仪内流场的分析[J].中国农机化学报,2014,35(2):310-313,329.Huang Yan,Zhao Manquan,Liu Hantao,et al.Analysis of the flow field of whirling separation sand sampler based on ANSYS FLUENT[J].Journal of Chinese Agricultural Mechanization,2014,35(2):310-313,329.
[6]宋涛,孟晓军,边炳传,等.分流对冲与多级扩容式集沙仪排气管参数优化与流场模拟[J].中国农机化学报,2018,39(8):27-32.Song Tao,Meng Xiaojun,Bian Bingchuan,et al.Flow field simulation and parameter optimization of exhaust pipe of a shunt-hedging and multi-stage expansion sand sampler[J].Journal of Chinese Agricultural Mechanization,2018,39(8):27-32.