Research and Design on a Portable Intravehicular Ultrasonic Leak Detector for Manned Spacecraft

Authors: Yan Rongxin, Sun Wei, Li Weidan

Abstract:

Based on the acoustics cascade sound theory, the mechanism of air leak sound producing, transmitting and signal detecting has been analyzed. A formula of the sound power, leak size and air pressure in the spacecraft has been built, and the relationship between leak sound pressure and receiving direction and distance has been studied. The center frequency in millimeter diameter leak is more than 20 kHz. The situation of air leaking from spacecraft to space has been simulated and an experiment of different leak size and testing distance and direction has been done. The sound pressure is in direct proportion to the cosine of the angle of leak to sensor. The portable ultrasonic leak detector has been developed, whose minimal leak rate is 10^-1 Pa·m³/s, the testing radius is longer than 20 mm, the mass is less than 1.0 kg, and the electric power is less than 2.2 W.

Keywords: Leak detection, manned spacecraft, ultrasonic, sound transmitting.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1130595

References:

[1] Yu Xinfa, Yan Rongxin. The research of leak testing technology in spacecraft on orbit (J). Spacecraft Environment Engineering, 2008，25 (2), 177-182 (in Chinese).
[2] Reusser R, Holland S D, Roberts R A. Array-based acoustic leak location in spacecraft structures (C).in AIP Conference Proceedings，2006，894: 1540-1547.
[3] Holland S D, Roberts R, Chimenti D E, et al. Two-sensor ultrasonic spacecraft leak detection using structure-borne noise (C). Acoustics Research Letters Online, 2005, 6(2), 63-105.
[4] Holland S D, Roberts R, Chimenti D E, et al. Leak detection in spacecraft using structure-borne noise with distributed sensors (J). Applied Physics Letters, 2005, 86: 174105.
[5] Song Juoho, Holland D Stephen, Chimenti D E. A spherically focused capacitive-film air-coupled transducer (C). AIP conference, 2006, 820: 908-915.
[6] Holland S D, Roberts R, Chimenti D E, et al. An ultrasonic array sensor for spacecraft leak direction Finding (J). Ultrasonics, 2006, 45: 121-126.
[7] Yan Rongxin，Li Weidan. Design of portable leak detector used for manned spacecraft based on ultrasonic (C).11th European Conference on Non-Destructive Testing (ECNDT 2014), October 6-10, 2014, Prague, Czech Republic.
[8] Zhang Qiang. Pneumatic Acoustics (M). Beijing National Defense Industry Press, 2012: 210-211 (in Chinese).
[9] Ma Dayou. Acoustic Manual (M). Beijing: Science Press, 1983:30-32(in Chinese).