气体传感器性能准确快速评价方法研究

Research on Accurate and Fast Evaluation De-vice Using for Gas Sensor Performance

本文构建了一款以微型舱为核心的气体传感器性能评价系统,由多组分动态配气单元、微型测试舱和数据采集分析单元三部分组成;利用SolidWorks软件对测试舱内腔结构建立物理模型,并在ANSYS FLUENT软件中选择标准k-ε方程(k为湍动能,ε为耗散率)对测试舱壁面处湍流流动和腔室内部气体层流状态进行模拟,实验研究了气体流速对三款传感器响应性能的影响,并采用压差法考察测试舱气密性。以甲醛及甲苯作为目标组分考察了Sensor W及Sensor Z的响应性能。与Sensor W标称值相比,用本装置的检测下限为0.1 ppm,灵敏度(Rg/Ra)为0.926,较其标称值均有所改善,结果更客观准确;在甲醛浓度500 ppb^10 ppm、甲苯浓度5 ppb^300 ppb范围内,Sensor Z的响应随着浓度增加稳步上升;可准确测量Sensor Z对甲醛和甲苯的响应时间(T90)分别为11 s和36 s,恢复时间(T10)分别为2 s和9 s。结果表明:本文构建的气体传感器性能评价系统具有内部流场稳定、浓度分布均匀、气密性好等特点,尤其适用于高灵敏气体传感器的低浓度响应能力测定及响应恢复时间的评价。

In this paper, an evaluation systemusing for gas sensor performance has been constructed, which comprised withthree parts: a multicomponent dynamic gas distribution unit, a micro testchamber as core and a data analysis unit. The simulations of gas flow statesfor the internal micro test chamber were employed via the standard k-ε equation(k is the turbulent kinetic energy, ε is the dissipation rate) in ANSYS FLUENTsoftware based on inner chamber structure modeling by SolidWorks software. Theeffect of flow velocity on three gas sensors performance and the tightness ofthe micro test chamber were investigated. The response performance of Sensor Wand Sensor Z was exhibited via the as-constructed evaluation device by usingmethanal and toluene as target components. In contrast to the nominal value,Sensor W has obtained more accurate and objective sensing properties, i.e. the lower detection limit (0.1 ppm)with the corresponding sensitivity ((Rg/Ra, 0.926).Sensor Z has been demonstrated excellent sensing response towards methanal andtoluene, range from 500 ppb - 10 ppm and 5 ppb - 300 ppb, respectively. Simultaneously,the response and recovery times of Sensor Z for methanal and toluene at 5 ppband 500 ppb respectively, were accurately measured. As the results, theevaluation system for gas sensor performance as-constructed in this paper hasthe advantages of stable internal gas flow field, uniform gas concentrationdistribution and satisfied gas tightness as well as the evaluation capabilityfor ultrasensitive and fast gas sensor.