Experimental and theoretical studies of cryogenic sealing

Funded by NASA Kennedy Space Center, this research project was to solve the liquid hydrogen leakage problem in the cryogenic system of Columbia space shuttle. A contracting-expanding self-sealing (CESSC) device was developed by making use of the thermal contraction ratio of dissimilar metals. A research cryostat providing with a high pressure and variable temperature test chamber was built to leak check the cryogenic fittings. A cryogenic research laboratory for the project was established in the Department of Mechanical Engineering, Florida Atlantic University. Both NASA KC126 fitting and the CESSC fitting were tested in the cryogenic testing system. A theoretical approach was also attempted to study the cryogenic leaking phenomenon. A finite element code was developed to simulate the thermal contraction for different CESSC designs. The ANSYS code was also used for the same purpose. The CESSC fittings were successfully used in the space program as well as in the superconducting projects. The principle of the CESSC seal has been extended to solve a variety of problems in cryogenic field.