基于CFD的气敏特性测试室气体均匀性仿真分析

Simulation analysis of gas uniformity in gas sensitive characteristic test room based on CFD

开发高性能的气体传感器,必须确保合格的传感器响应测试。而大多数发生在传感器表面的化学/物理过程都受到测试室内气体分布均匀性的影响。通过计算流体动力学(CFD)仿真,设计了一种气敏特性多通道测试室。首先,对测试室结构建立三维模型并采用滑移网格处理;然后,采用kω-SST和SAS湍流模型计算不可压缩条件下的Navier-Stokes方程;最后,经后处理,获得室内空气龄、流速场均匀性综合信息。结果表明:当孔径比β=0.67时,传感器表面流量覆盖率为90.41%,流速阶梯性变化对传感器稳定性影响小于4.06%,相较于其他的孔径比,对响应时间的稳定性提升了230%,为实际的测试室开发提供了理论依据。

To develop high performance gas sensors,it is imperative to ensure qualified sensor response testing.Most of the chemical/physical processes that occur on sensor surface are affected by the uniformity of the gas distribution in test chamber.A multi-channel test room for gas sensitivity characteristics is designed through computational fluid dynamics(CFD)simulation.Firstly,a three-dimensional(3D)model of the test chamber structure is established and processed by sliding mesh.Then,the Navier-Stokes equation under incompressible conditions is calculated by kω-SST and SAS turbulence models.Finally,after post-processing,uniformity comprehensive information on indoor air age,flow velocity field is obtained.The results show that when the aperture ratioβ=0.67,the surface flow coverage of the sensor is 90.41%,and influence of step change of flow velocity on the stability of the sensor is less than 4.06%.Compared with other aperture ratios,the stability of the response time is improved by 230%,which provides a theoretical basis for the actual development of test chambers.