基于 MEMS 的量热式传感器气体流量测量的模型研究

气体流量测量广泛应用于呼吸监测、管道运输等领域。本研究细致分析了MEMS量热式传感器温度一维分布模型中的热边界层参数，进行了相应的经验修正。并且在温度一维分布模型的基础上，针对具有两对上下游测温电阻芯片结构的MEMS量热式传感器，提出了一种新的传感器输出电压关于气体流量的半修正理论模型。该理论模型能够适用于不同类型的单介质气体。同时，开展了N₂、CO₂流量测量实验，与理论模型进行对比，证明所提出的理论模型可以正确预测不同气体介质的流量，其中针对CO₂测量介质的均方根误差为0.15%。此外，结合理论分析，提出了一种高精度，拟合形式简单、针对确定气体适用性更好的测量模型，其中针对CO₂测量介质的均方根误差为0.05%。

Modelling of gas flow measurement based on MEMS calorimetric sensors

Gas flow measurement is widely used in respiratory monitoring, pipeline transport, and other fields. In this study, the thermal boundary layer parameters in the one-dimensional temperature distribution model of MEMS calorimetric sensors are carefully analyzed, and the corresponding empirical corrections are made. On the basis of the one-dimensional temperature distribution model, a new semi-corrected theoretical model of the sensor voltage output with respect to the gas flow rate is proposed for MEMS calorimetric sensors with two pairs of upstream and downstream temperature measuring resistor chip structures. The theoretical model can be applied to different types of single-medium gases. Meanwhile, N2 and CO2 flow measurement experiments are implemented to compare with the theoretical model, which shows that the proposed theoretical model can accurately predict the flow of different gases, and the RMSE is 0. 15% for the CO2 measurement medium. In addition, combined with the theoretical analysis, a high-precision measurement model with a simple fitting form and a better applicability to deterministic gases is proposed, and the RMSE is 0. 05% for the CO2 measurement medium