三丝结构水平姿态传感器敏感机理的研究

Study of the Sensitive Mechanism of the Level-gesture Sensor with Three-thread Structure

采用有限元法,利用ANSYS-FLOTRAN CFD软件,计算了在不同倾斜状态下三丝结构敏感元件内的温度场和流场。计算结果表明,加热热电阻丝在敏感元件内形成一定的温度场和流场,倾斜时温度场和流场不再对称分布;在水平状态时两检测热电阻丝处的气流速度相等,两检测热电阻丝的电阻相等,电桥电路输出为零;在倾斜状态下时,两检测热电阻丝处的气流速度之差随着倾斜角度而变化,引起两检测热电阻丝电阻之差也随之变化,电桥输出一个对应于倾斜角度的电压。有限元计算法为三丝结构气流式水平姿态传感器优化设计开辟了有效的研究途径。

The temperature and flow fields of the sensing device with three-thread structure in different tilting states was calculated by using the ANSYS-FLOTRAN CFD program and with the method of finite element. The results showed that a heated hot wire formed a definite temperature-field and fluid-field within the sensing element when it was gradient, and the two fields were no longer distributing symmetrically. In the level state, the velocity of gas flow at both detected hot wires was equal, so the resistance of both detection hot wires were also equal and the output of the Bridge circuit was zero; while in the incline state, the velocity difference of gas flow at both hot wires will change with the tilt angle, so result in changing of the resistance difference of both hot wires, the Bridge outputs a voltage signal of corresponding to the tilt angle. This calculated method provided an effective way for the optimization design of gas-flow level-gesture sensor with three-thread structure.