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

Analysis of design parameters of sandbox of the shunt-hedging and multi-stage expansion combined automatic sand sampler

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 istoo high,the airflow will easily impact the weighing sensor at the bottom of the sandbox,affecting the accuracy of the measurementdata.In this paper,the wind-sand separator and sandbox of the shunt-hedging and multi-stage expansion combined automatic sandsampler are taken as study models,the sandbox is regarded as the downlink space of the airflow at the outlet,the downlink space isconnected with the wind-sand separator of the sand sampler to form a connecting body,and then using Gambit and Ansys Workbenchsoftware to analyze the downstream space of different parameters,and carried out a experimental verification.The result showed thatdesign parameters of sandbox of the shunt-hedging and multi-stage expansion combined automatic sand sampler will neither affect theflow field in the wind-sand separator nor affect the separation of wind-sand in the wind-sand separator,but it has great influence onthe airflow at the outlet,when the design parameters of the sandbox are satisfied,when L≥0.5 D1and D2≥2 D1or L≥D1and 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.