MEMS Thermal Film Gas Flow Sensor Dust Removal Device Based On Cyclone Principle

The MEMS hot-film gas flow sensor has the advantages of high measurement accuracy,fast response and good repeatability,but its measurement accuracy can be easily affected by the dust from the gas.Cyclone dust removal technology has the advantages of simple structure,high separation efficiency and large gas flow rate.In order to improve the dust-proof ability of MEMS gas flow sensor and meet the needs of some special working occasions,a dust removal device based on cyclone principle is designed.Theoretical calculation and FEM simulation are used in structural design and performance research of the cyclone dust removal.According to the requirement of flow rate and velocity when the sensor works,the ranges of sizes of dust removal device are selected.The rotational degree of flow field and the force of the dust are analyzed mathematically.By estimating the characteristics of the cyclone and dust removal efficiency,the appropriate ranges of sizes are determined.The FEM simulations of dust removal device with different sizes are carried out.According to the orthogonal test method,the influences of each dimensional parameter on dust removal efficiency are analyzed.The flow field characteristics of two-phase flow and the dust removal efficiency in different conditions are analyzed by FEM simulations.According to the movement of airflow and dust particles,the two-phase flow field is divided into different parts.The influence and mechanism of each part on the dust removal efficiency are studied.In order to verify the results of FEM simulations,the ratio of branch flow,pressure loss and dust removal efficiency are measured in different working conditions.The difference between the experimental and FEM simulation results is very small.The FEM simulation results are turned out to be acceptable.