Conveners
C1Po2B: Non-Aerospace Coolers I: GM and JT Coolers
- Richard Dausman (Bluefors Cryocooler Technologies, Inc.)
- Xihuan Hao (Bluefors Cryocooler Technologies, Inc.)
Cooling performance in positive displacement cryocoolers is dependent on the relationship between the compressor’s displacement and the cold head’s displacement. An experimental investigation explored the relationship between compressor and cold end displacement for a single-stage gas-driven GM-type cold head operated at different frequencies. As loss mechanisms can be frequency related, the...
The NMR magnet is cooled by two kinds of cryogens. The boil-off rate of the cryogen in a general NMR magnet is 20 cc/h for liquid helium and 200 cc/h for liquid nitrogen. We have developed a zero boil-off system that can greatly suppress the evaporation of liquid helium and liquid nitrogen.
This system is equipped with a GM cryocooler, with a nitrogen cooling chamber on the 1st stage and a...
A cryogenic mixed refrigerant Joule-Thomson refrigerator was developed to apply the cryogenic etching process with non-flammable constituents. 2-stage cascade type mixed refrigerant Joule-Thomson refrigerator was analyzed to figure out the coefficient of performance of the refrigeration cycle. The working fluid of mixed refrigerant Joule-Thomson refrigerator is non-flammable mixture of...
A 4 K Helium Joule-Thomson (JT) refrigeration system based on ejector technology is presented in this paper to enhance the thermodynamic efficiency, which could also decrease the lowest cold head temperature and avoid higher suction pressure of the compressor. This paper studies the influence on the cryocooler performance of ejector parameters using one-dimension numerical simulation. A...
