气力板式蔬菜排种器气室真空流场仿真分析

A simulation analysis on vacuum flow field for an air chamber of pneumatic plate-type vegetable seed metering device

【目的】优化气力板式蔬菜排种器气室结构参数,简化气室气流体为定常不可压的湍流模型.【方法】选用ANSYS软件的FLOTRAN模块,对不同气室结构参数进行仿真分析.【结果和结论】相对整体矩形空腔结构,矩形横槽和纵槽连通气室结构更能节省气流量,提高整体强度;双气源口结构相比单气源口结构相对压力损失小,流场分布均匀性更好;优化的气源口位置在距排种器两侧边缘第4个和第5个吸种孔之间;气室槽深越大,过渡区域相对压力损失越小,吸种孔入口处的相对压力和速度分布越均匀,但排种器整体结构尺寸增大,气腔内形成一定相对压力的稳定流场所需时间更长,槽深取4 mm综合较好.验证试验结果表明,在吸种孔入口中心处,仿真分析结果与实际测量结果比较接近,趋势上具有较高一致性,表明仿真分析优化气室结构参数可行.

[Objective] To optimize chamber structure parameters of the pneumatic plate-type vegetable seed metering device , and to simplify the vacuum flow field in the air chamber as steady , regular, incom-pressible and turbulent fluid .[Method] The FLOTRAN module of ANSYS software was applied to simu-late and analyze the air chamber with different structure parameters .[Result and conclusion] Compared to the rectangular cavity air chamber structure , the rectangular groove connected air chamber structure could save more gas flow and improve the overall strength .Pressure loss of double outlet was less than single outlet, and flow field uniformity of double outlet was better .The optimized air source location was between the fourth and the fifth suction holes calculated from both sides of the metering device .Increas-ing channel depth could reduce pressure loss at transition region and ensure more uniform pressure and velocity distribution .But if channel depth increased , the size of metering device would increase corre-spondingly , and the time for forming steady flow would be longer .According to simulation results , 4 mm channel depth was optimized .Verifying tests of the air flow field in the vacuum chamber of seed metering device show that the simulation analysis results are comparatively consistent with the actual measurement results, with a consistent pressure distribution trend .This proves the feasibility of the numerical simula-tion method.