Meeting start time: 2:00 p.m.

Members Present: Lee, Sage, Mathew, Jose

Fixed Issues:

  • Leaks had been found on the VT and fixed utilizing indium and pipe tape sealing methods (Jose)

Known Issues:

  • During testing on 7/18/2017 a full gas bottle was drained in ~10 minutes by the system at a working pressure of 350 psi. This has created issues regarding available resources as well as time management. After discussing the issue with Jake, it seems that installing the gas boosters is the next route that should be taken as well as possibly closing the system. Since Nitrogen is relatively cheap, its monetary expense is not much of an issue currently.


From today:

  • A J-T valve was installed on the hot-end of the vortex tube to control back pressure and flow on the system.
  • Currently testing to optimize J-T valve position at 350 psi for optimal cooling capability.
  • Operating with fully open J-T valves at 350 psi saw a drop in ~18 K in roughly 10 minutes.
  • Operating with a fully closed J-T valve on the hot-end saw cooling but at the expense of efficiency. The observations are explored as follows:
  1. Initially saw ~ 1K of cooling on the cold-end.
  2. Cold-end then began warming back up.
  3. After ~ 4 minutes, gradual cooling on the cold-end could be seen.

** We think that cooling may be occurring even with a fully closed J-T valve on the hot-end for a few reasons. One idea is that while the hot and cold gas is being separating, as the hot gas reaches the J-T valve it is forced back into the VT, mixing with the cold-gas that is then forced out the cold-end. This then decreases the rate of cooling on the cold-end, leading to the idea that closing the hot-end is extremely inefficient.


Current Issues:

  • Still do not have a recording system for temperature measurements. Lee is currently working to get the measurement set up through LabView or Excel.