At Flow Systems we continually work towards improving the uncertainty and repeatability of the flow
measurements provided by our equipment. A large contributor to the total uncertainty of the High Flow Test
Stand was the +/- 0.35% nozzles calibrations. In an effort to improve these calibrations Flow Systems built two
calibration test stands for the Colorado Engineering Experiment Station, Inc (CEESI). These stands employ flow
standards that are directly calibrated by NIST's best in the world PVTt systems and use highly accurate
instrumentation and advanced control systems. With these tests stands CEESI can now provide +/- 0.13 to 0.20%
calibrations on the nozzles used in High Flow Test Stand which significantly reduces the total system uncertainty.
In addition to improving the High Flow uncertainty Flow Systems also wanted to improve the test stand's
repeatability and reproducibility. In this effort we are offering a liquid heat exchanger package for our High Flow
Test Stands. Three tube and shell type heat exchangers are used for the inlet of the small plenum and the outlet
of the small and large plenums. These units are built with a combination of steel ends for durability, an aluminum
shell to reduce weight, and copper tubes to provide significant heat transfer. For the inlet of the large plenum a
pressure vessel that contains three series mounted oil coolers is used. These heat exchangers were specifically
designed to provide the required heat transfer while minimizing pressure drop as compared to typical
commercially available heat exchangers. Propylene glycol, a non-toxic fluid, is pumped thru the plenum heat
exchangers and acts as the medium for heat transfer. Heat is rejected or collected as required from the fluid via a
radiator and system controlled fan that vents out the underside of the test stand. The full system is built into the
flow stand and doesn't have any additional facilities requirements.