FEM Analysis of Micro-machined Airflow Accelerometer´s Sensitive Mechanism

The sensitive mechanism of micro- machined airflow accelerometer is explained. Using the finite element method, the stream field by heat source, with different input accelerations, has been obtained. The numerical results are as follows: Without acceleration, the velocities of airflow at two thermistors are equal, so the current of both thermistors are also equal. The output of the bridge circuit is zero. With input acceleration, the velocity difference of airflow at two thermistors will change with the acceleration, so lead to changing of the current difference of both thermistors; the bridge outputs a voltage signal of corresponding to the acceleration. This calculated method provides a new road for optimization of micro-machined airflow accelerometer.