Research on Orifices Distribution Effects on Accuracy of Flush Air Data Sensing System

Abstract

Being the data source of flush air data sensing(FADS) system, the distribution of orifices had direct effects on the accuracy of FADS system. Numerical computations based on Newton model and filtering algorithm are conducted. For Spherical aircraft head as an example, virtual flight path covering Mach number 4.30~15.79, height 25~70 kilometers is defined. Spherical nose is presented for FADS orifices arrangement. Results of clock angle effect, cone angle effect and asymmetric distribution effect are presented and analyzed. Computational results show that increasing the number of pressure points along the circumference can improve the measurement accuracy of the FADS system. However, there is a threshold value. When the number of pressure points is the same, increasing the cone angle can significantly improve the measurement accuracy of FADS. The asymmetric distribution of the orifices has no effect on the measurement accuracies.

Keywords

• flush air data sening system
• orifices
• clock angle effect
• cone angle effect