2.7 Conduct cryogenic testing

Four cylinders from each configuration were tested cryogenically. Each test cylinder was assembled into the test fixture, filled with liquid nitrogen, sealed, and pressurized (using compressed air) to at least its minimum test pressure. After pressurizing one time, a bleed valve was used to depressurize the cylinder to ? of its minimum test pressure. This process was repeated a total of three times for each test cylinder. Following the pressurizing and depressurizing, the test cylinder was then taken out of the test assembly and allowed to come back up to ambient temperature. This process constituted one "cycle". (A chart documenting pressure and temperature of a typical test "cycle" can be seen in Appendix A of this report.) The test cylinder was then hydroburst using HEI's hydrostatic burst pump. The photo below left shows the cryogenic protective test chamber with a portion of the test setup being readied for a test and the photo below right shows a "frosty" cylinder that recently completed a cryogenic cycle next to a cylinder that had not yet been tested.

A design of experiments such as conducted for this effort typically provides only an indication of the parameters that might or might not improve or degrade a product or process. Usually no "final answers" are identified. However, having said that, the results from this experiment have provided some extremely interesting and valuable data. The following table summarizes the data obtained from cryogenic testing.

HEI TEST DATA SUMMARY POST-CRYOGENIC TESTING PERFORMANCE

The remaining cylinders from Dr. DeLay were also tested in the same manner as HEI's test cylinders. Since only one cylinder from each configuration was tested, it was impossible to get an actual CV. As a consequence, a CV of 3% has been assumed. This is something that HEI would pursue more vigorously, if granted a Phase II follow-on contract. The information gathered from hydrostatic burst testing following cryogenic testing is presented in the following table.

NASA TEST DATA SUMMARY POST-CRYOGENIC TESTING PERFORMANCE

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HyPerComp Engineering, Inc.; SBIR NAS8-03027 Final Report