Research on the natural convection effects of the fluidic gyroscope

The effect mechanism for the natural convection of the fluidic gyroscope was explained. Using the finite element method, building an entity model, the finite element simulation was conducted by a series of procedures, such as meshing, applying loads and solving. Then the flow field in the sensitive element was obtained in the different inputting angular rate. The results are as follow: (1) With the existence of natural convection, when there is no inputting angular rate, the airflow velocity difference Δv at the two hotwires will change with the tilt angle, so the detection result is that the bridge outputs a zero voltage. In static status, the airflow velocity shows a symmetry distribution through the central axis in the cavity, the flow velocity is equal at the two hotwires, so the current of both hotwires are also equal. The bridge circuit outputs zero, and the mean absolute deviation is 16mv. When the sensor´s sensitivity is 40mV/°s, the error reaches 0.4°/s. So it leads to the change with the zero reproducibility. (2) With the existence of natural convection, with the inputting angular rate, the airflow velocity difference Δv at the two hotwires will also change with the tilt angle, different tilt angles make the mean comparative error of detecting bridge voltage U reach 2.4% and the error reaches to 0.03°/s, so it lead to the instability of sensibility. (3)The influence of natural convection for fluidic gyroscope´s zero reproducibility is greater, but for the stability of sensitivity is smaller. In this paper, both theory gist and experiment have been given to eliminate the influence of natural convection, and improve the zero reproducibility and sensitivity stability for the fluidic gyroscope.