基于气溶胶理论的热膜气体流量传感器颗粒物沉积机理与实验研究

项目名称： 基于气溶胶理论的热膜气体流量传感器颗粒物沉积机理与实验研究

项目编号： No.51475242

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 机械、仪表工业

项目作者： 孙中圣

作者单位： 南京理工大学

项目金额： 80万元

中文摘要： 针对热膜式气体流量传感器受污染后测量精度下降的问题，基于气溶胶理论对灰尘、油雾等微小颗粒物在热膜表面的沉积机理进行分析和试验研究。与气溶胶在空调通风、呼吸系统等领域的应用研究不同，本项目考虑传感器热膜表面形成的热场和电场，通过建立颗粒物的运动和受力模型，分析颗粒物在流道内的输运过程和热膜表面的沉积速度，研究影响沉积速度的主要因素。在此基础上，利用仿真和试验分析颗粒物在热膜表面的沉积数量、厚度和分布的变化规律以及由颗粒物沉积引起的粗糙度变化对沉积速度的影响，研究传感器受污染后精度的变化，建立沉积污染物与测量精度之间的关系模型，预测传感器精度的变化趋势。为减少颗粒物在热膜表面的沉积，基于气旋原理设计集成于传感器的小型颗粒物分离装置，利用有限元模型对结构参数进行设计优化，并通过试验分析其除尘效率。该研究可为传感器的设计改进提供参考，对于提高抗污染能力和精度的保持性，拓宽其应用领域具有重要意义。

中文关键词： 热膜式气体流量传感器；气溶胶；颗粒沉积；气旋原理

英文摘要： Aiming at the measurement accuracy decrease after the hot-film air flow sensor is contaminated, the deposition mechanism of fine particles such as dust and oil mist on the hot-film surface is analyzed and researched by experiment based on the aerosol theory. In this project, the electric and thermal fields on the hot-film surface are considered differing from aerosol research in the field of the air-conditioning ventilation system and respiratory tract. The transport process in the flow channel and deposition velocity on the hot-film surface is analyzed by building the movement and force model of particle, and the main factors effecting on deposition velocity are researched. Based on the research above, the deposition quantity, thickness and distribution of particles on the hot-film surface are analyzed by simulation and experiment. The effect of roughness change caused by particle deposition on deposition velocity is also analyzed. Accuracy variation of the contaminated sensor is researched, and the relation model between contamination and measurement accuracy is build in order to forecast the accuracy variation tendency. The cyclone-type small particle segregation device is designed which can be integrated into hot-film air flow sensor. Its structure parameters are analyzed and optimized by the finite element model, and the dust collection efficiency is analyzed by experiment. The research of this project can provide the reference for sensor design, and have important significance for improving the anti-contamination ability and accuracy stability and broadening its application field.

英文关键词： hot-film air flow sensor;aerosol;particle deposition;cyclone theory