Loading...
Please wait, while we are loading the content...
Similar Documents
Cryogenic testing of different seam concepts for multilayer insulation systems
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Fesmire, J. E. Johnson, Wesley L. |
| Copyright Year | 2009 |
| Description | Recent testing in a cylindrical, comparative cryostat at the Cryogenics Test Laboratory has focused on various seam concepts for multilayer insulation systems. Three main types of seams were investigated: straight overlap, fold-over, and roll wrapped. Each blanket was comprised of 40 layer pairs of reflector and spacer materials. The total thickness was approximately 12.5-mm, giving an average layer density of 32 layers per centimeter. The blankets were tested at high vacuum, soft vacuum, and no vacuum using liquid nitrogen to maintain the cold boundary temperature at 77 K. Test results show that all three seam concepts are all close in thermal performance; however the fold-over method provides the lowest heat flux. For the first series of tests, seams were located 120 degrees around the circumference of the cryostat from the previous seam. This technique appears to have lessened the degradation of the blanket due to the seams. In a follow-on test, a 20 layer blanket was tested in a roll wrapped configuration and then cut down the side of the cylinder, taped together, and re-tested. This test result shows the thermal performance impact of having the seams all in one location versus having the seams clocked around the vessel. This experimental investigation indicates that the method of joining the seams in multilayer insulation systems is not as critical as the quality of the installation process. |
| File Size | 5374506 |
| Page Count | 10 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_20130012959 |
| Archival Resource Key | ark:/13960/t3713208z |
| Language | English |
| Publisher Date | 2009-04-22 |
| Access Restriction | Open |
| Subject Keyword | Mechanical Engineering Leakage Aluminum Liquid Nitrogen Cryogenics Cylindrical Bodies Temperature Profiles Seams Joints Multilayer Insulation Data Bases Heat Flux Cryostats Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
