摘要
为了研究锥管的流阻特性,采用数值模拟的方法对最小截面宽度为150μm,高度为150μm的平面锥管进行分析,得到雷诺数在100～2 000范围内,收缩方向流阻系数与扩散方向流阻系数的比值λ随锥角θ及流管长宽比l/w变化的规律.结果表明:流管锥角越小,θ及l/w对λ值的影响越大,且流管的流阻特性随θ和l/w的变化发生了转换;在Re=100与Re≥500两种工况下,流管扩散方向流阻系数ξd随θ及l/w的变化趋势相反;Re=100时,流管多呈沿扩散方向流阻较小的Ⅰ类流管特性,θ=20°,l/w=20的流管的λ值最大达到1.22;Re≥500时,流管多呈沿收缩方向流阻较小的Ⅱ类流管特性,θ=20°,l/w=1的流管的λ值最小达到0.63.说明不同雷诺数流动下流管的流阻特性相差较大,不同工况下可通过选用合适的流管结构参数提高无阀压电泵的工作效率.
The flow in a tube with the narrowest width 150 μm and the depth 150 μm was studied numerically,two flow resistance coefficient curves versus cone angle θ and length-width ratio l/w were obtained when the tube was subject to convergent and divergent flows at a Reynolds numbers ranged in 100-2 000.The results show that the smaller the cone angle θ,the more significantly dependent on θ and l/w the flow resistance coefficient λ,and a transition occurs in flow resistance feature.The relations of λ to θ and l/w are different at Re=100 and Re≥500 obviously.When Re=100,most of tubes present the typeⅠ tube characteristics that flow resistance coefficient in the divergent direction is less than in the convergent one,and λ reaches a maximum 1.22 at θ=20°and l/w=20.When Re≥500,most of tubes show the type Ⅱ tube characteristics which is contrary to typeⅠ,and λ reaches a minimum 0.63 at θ=20°and l/w=1.The results show that the flow resistance coefficient of flat-walled diffusers highly depends on Reynolds number.In order to improve performance of the valveless piezoelectric pump,appropriate geometrical parameters should be chosen in the pump design according to the actual working condition of the pump.
出处
《排灌机械工程学报》
EI
北大核心
2012年第5期532-537,共6页
Journal of Drainage and Irrigation Machinery Engineering
基金
江苏高校优势学科建设工程项目
江苏大学高级专业人才科研启动基金资助项目(11JDG091)
关键词
无阀压电泵
平面锥管
流动特性
转折点
数值模拟
valveless piezoelectric pump
flat-walled diffuser
flow characteristic
transition point
numerical simulation
