Main Article Content
Abstract
The fabric of a Lighter-Than-Air (LTA) system experiences permeation of Helium over a period of time. Due to the small size of the molecules of Helium, it permeates through the intermolecular spaces of the fabric. This leakage increases with time due to the degradation of the fabric. LTA systems need to be deployed for long durations. The loss of Helium due to permeation reduces the relative lift of the LTA system. The unknown permeation rates thus lead to uncertainties in the deployment time of the system. This paper describes the design and fabrication of a test rig to determine the permeability of Helium through different fabrics. This method involves a permeation cell divided into upper and lower chambers arranged to hold a specimen fabric between them, with the provision of a continuous supply of Helium in the lower chamber. A Phoenix L300i Helium Leak Detector (HLD) is connected to the upper chamber to detect Helium and measure its concentration. The further objective of this research is to study the variation of helium permeability through the fabrics at constant temperature and input pressure with time.
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References
- Noll, J. R., "Determination of Lift Gas Leakage Rate for a Stratospheric Airship Hull", 11th ATIO Conference-19th LTA System Conference, Virginia Beach, 22 September, 2011, Serial No.78228.
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- van Rooyen, L. J., Karger-Kocsis, J., Vorster, O. C. and Kock, L. D., " Helium Gas Permeability Reduction of Epoxy Coatings by Incorporation of Glass Flakes", Journal of Membrane Science, 2013, pp.203-210.
- Crosby, E. J., "Apparatus and Method for Measuring Permeability", RCA Corporation, New York, 22 October, 1976, Serial No.734728.
- Barchenko, V. T., Lisenkov, A. A. and Vinogradov, M. L., "Apparatus and Method for Determining the gas Permeability and Flux of Helium Through the Materials and Coatings", Journal of Physics, Conference Series, 567, 2014, 012002.
References
Noll, J. R., "Determination of Lift Gas Leakage Rate for a Stratospheric Airship Hull", 11th ATIO Conference-19th LTA System Conference, Virginia Beach, 22 September, 2011, Serial No.78228.
Ashford, R. L., Bata, B. T. and Walsh, E. D., "Measurement of Helium Gas Transmission Through Aerostat Material", Aerostat Systems Department, TCOM Corporation, Serial No.831986.
Fernandes, M. A. F., Yelve, N. P. and Pant, R. S., "Leak Testing of Envelopes of LTA System Systems", Indian Institute of Technology Bombay, Mumbai.
Kammermeyer, K. and Brubaker, D. W., "Permeability Tester", State University of Lowa, Lowa City, 12 June, 1953, Serial No.361202.
Doyle, J. M., "Permeability of Noble Gases Through Kapton, Butyl, Nylon, and Silver Shield", Department of Physics, Harvard University, Oxford Street, Cambridge, 19 January 2010, Serial No.267271.
Yao, X. F., Lei, Y. M., Xiong, C. and Wu, Q., "Mechanics Analysis on Helium Leakage of Flexible Composites", Tsinghua University, Beijing, China, 05 September, 2012, Serial No.603-612.
van Rooyen, L. J., Karger-Kocsis, J., Vorster, O. C. and Kock, L. D., " Helium Gas Permeability Reduction of Epoxy Coatings by Incorporation of Glass Flakes", Journal of Membrane Science, 2013, pp.203-210.
Crosby, E. J., "Apparatus and Method for Measuring Permeability", RCA Corporation, New York, 22 October, 1976, Serial No.734728.
Barchenko, V. T., Lisenkov, A. A. and Vinogradov, M. L., "Apparatus and Method for Determining the gas Permeability and Flux of Helium Through the Materials and Coatings", Journal of Physics, Conference Series, 567, 2014, 012002.