1.College of Quality and Technical Supervision,Hebei University,Baoding,Hebei 071002,China
2. National Institute of Metrology,Beijing 100029,China
3. Zhengzhou Institute of Advanced Metrology Technology,Zhengzhou,Henan 450001,China
Abstract:The accuracy of the nulling and non-nulling of the S-type pitot tube is quite different under different working conditions. The influence of wind velocity,velocity angle of attack and structural parameters on the accuracy of nulling and non-nulling of the S-type pitot tube is studied through the wind tunnel. The results show that when the wind velocity changes from 5 to 30m/s, the maximum difference in the measurement accuracy of pitot tube is more than 10% in nulling and non-nulling at different velocity angles of attack. The pressure change of the static pressure hole in nulling and non-nulling is the main reason for the measurement error of the pitot tube at large velocity angles of attack. The pitot tube with smaller outer diameter, larger distance between total and static pressure hole, bending angle of measuring end between 15° and 30°, and smaller inner diameter of pressure tapping has higher measurement accuracy in both nulling and non-nulling.When the pitch angle is positive,the measurement accuracy of nulling is better than that of non-nulling. When the pitch angle and yaw angle are both 45°, the difference of measurement accuracy reaches the maximum, which is greater than 70%.
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