气动充放气系统二维非定常流场数值模拟

摘要

以典型气动系统为研究对象，考虑系统内部气体、元件和环境空气之间的耦合传热，将系统内部流场、元件和外部空气作为整体进行研究，建立气动充放气系统的二维模型，采用湍流κ-ε两方程模型，利用有限体积法(FVM)和动网格技术对充放气过程进行计算，得到系统内气体状态参数。在充放气过程中，气体速度最大值出现在放气管出口处，可达到超声速范围；气缸中温度梯度主要存在于内壁面处。在系统元件中，进气节流口壁面温度的上升幅度最大，放气节流口壁面及紧邻的气管壁面温度降幅最大。通过试验验证本方法的可行性，为非定常流场的计算和分析提供参考。%Considering the coupling heat transfer of pneumatic components, air inside the system and ambient air, the flow field inside system, components and air outside system of typical pneumatic system treated as research object were investigated as an entirety. And the two-dimension model of pneumatic charging and discharging system was putted forward. The unsteady flow field was calculated by finite volume method (FVM) and dynamic mesh with the turbulence k-ε model. The results show that the air's maximal velocity appears at the outlet of the discharging pipe, which is faster than speed of sound in the charging and discharging process, and the temperature gradient inside cylinder exists nearby the cylinder wall. Among the components, the temperature of charging speed controller rises most, and the temperature of discharging speed controller and the neighboring pipe reduces most. The calculation results are consistent with those of experiment, which validates the proposed method is feasible. It illustrates a new way for calculation and analysis of unsteady flow field.