MEMS流速仪流体动力学设计

CFD Design of Current Meter Based on MEMS

针对MEMS技术在流速测量的领域的应用,设计了一种基于MEMS技术的在线流速仪。为了优化传感器探头结构设计与芯片选型,利用CFD方法建立流速仪的流体动力学模型,对其施加外部复杂对流-传热耦合热边界条件,进行流固耦合传热计算,得到不同直径的流速仪温度场分布。采用遗传算法对CFD方法计算结果进行拟合,建立了探头温度T与水流速度V及探头直径D之间的修正方程。测试结果表明:传感器探头温度随着水流速度的增加而呈指数形式减小,随着探头外径的增加而减小。当水流速度小于0.1m/s时,探头温度随速度减小变化较快,即该量程范围内测量精度较高。

Aiming at the application of MEMS technology in the field of velocity measurement, based on MEMS technology an online current meter was designed. In order to optimize the sensor probe structure design and chip selection, the flow of fluid dynamics model was established by the method of CFD. The current meter temperature field distribution of different diameter was developed from the fluid-structure coupling heat transfer calculation, for the external convective heat transfer coupling-complex thermal boundary conditions of the sensor. The modified equation of the probe temperature T and the flow velocity V and pipe diameter D was established, with the method of genetic algorithm, applying to fit the calculation results of CFD. Test results show that： the temperature of sensor probe decreases in the form of exponential with the increase of flow velocity and decreases with the increase of the probe diameter. When the flow rate is less than 0. 1 m/s, the temperature of sensor probe decrease sharply with the reduce of flow velocity, the precision is higher within the speed range.