Study on Influence on Sensitive of Thermosensitive Element to Open Jet Gyroscope

Abstract

This paper describes the effect mechansim of sensitive of thermosensitive element to open jet gyroscope. When different angular rate is applied, the distribution of airflow velocity at thermosensitive element is calculated by using fluid-solid coupling. The result shows that when angular rate about Z axis is applied, the distance between thermal resistance wires of d=0.6mm can decrease the influence of vortex inside of jet sensing cavity. Then, the temperature of thermal resistance wire is changing fast, which can increase the output voltage of Wheatstone Bridge and improve the sensitive of open jet gyroscope. The jet gyroscope can be applied in rugged environment with the virtue of supporting high overload and low cost etc. [1]. Open jet gyroscope is miniature gyroscope that the structure is simpler. Thermal resistance wire is thermosensitive element of open jet gyroscope and the detection of angular rate is carried out by Wheatstone Bridge consist of thermosensitive element. When the gyroscope has the angular rate input, the airflow velocity of two symmetrical thermal resistance wire is different. With the increasing angular rate, the difference of airflow velocity is increasing at the mean time. Accordingly, this causes the changes of current crossing two thermal resistance wire. Furthermore, the output of Wheatstone Bridge is voltage corresponding to angular rate. This paper calculates the flow field distribution of jet sensing cavity inside of open jet gyroscope when different angular are applied. Additional, It studies the difference of airflow velocity when there are different distances between two thermal resistance wires, which lays foundation for the set of thermosensitive element.