Self evacuated multilayer insulation of lightweight prefabricated panels for cryogenic storage tanks
Year: 1968
Type: article
Abstract: A new concept for simplifying the application of radiation-shield insulation to cryogenic tanks was developed and tested for both ground and space performance.A vacuumtight flexible casing of laminated aluminized Mylar encloses the multilayers, forming panels that are bonded to tank walls in an overlapping shingle arrangement.The panels, weighing only 0.34 pound per square foot (1.66 kg/m ), a r e filled with carbon dioxide (COS) gas which cryopumps to provide required vacuum when the tank is filled with a cryogen.The thermal performance of this insulation was determined in flat-plate and cylindrical calorimeters.Of the many materials tested in the flat-plate calorimeter, polyurethane foam was chosen as the separator between radiation shields because of its small increase in heat flux when compressed to 14.7 psi (10.13 N/cm ) in panels evacuated in the atmosphere.During ground tests, insulation panels as large as 3 by 6 feet (0.91 by 1.83 m) were mounted on a cylindrical calorimeter of liquid hydrogen and cryopumped to at least 5 x 1 C 3 torr ( 6 .6 6 ~1 0 -~ N/cm2).This procedure resulted in a heat flux of 23 Btu per hour per square foot (261 000 J/(hr)(m )) for an external temperature of 70° F (294' K).In simulated space tests, panels evacuated by outside vacuum resulted in a heat f l u x of 0.86 Btu per hour per square foot (9770 J/(hr)(m )) with outside surfaces at 70' F (294' K).
Authors: R. P. Dengler, Laura Niendorf, Gilles Nies, P. J. Perkins
Institution: Glenn Research Center
Language: English
Subfield: Aerospace Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W45328102