Take a sneak peek at the new NIST.gov and let us know what you think!
(Please note: some content may not be complete on the beta site.).
NIST Authors in Bold
|Author(s):||Ryan J. Lewis; Yunda Wang; Mu Hong Lin; Marcia L. Huber; Ray Radebaugh; Yung-Cheng Lee;|
|Title:||Enthalpy change measurements of a mixed refrigerant in a microcryogenic cooler in steady and pulsating flow regimes|
|Published:||August 29, 2012|
|Abstract:||Micro cryogenic coolers (MCCs) are useful to a number of small electronic devices which require low cooling power. The cooling power of MCCs operating with mixed refrigerants in a Joule-Thompson (J-T) cycle can be calculated based on enthalpy calculations for the mixture. This letter demonstrates a method to measure the isothermal enthalpy change in a mixture undergoing J-T expansion in an MCC for different refrigerant flow regimes. This shows that the enthalpy change for a mixture undergoing steady flow is an order of magnitude below that calculated; whereas the enthalpy change for the mixture undergoing pulsating flow agrees with the calculations below a certain temperature, and is over-predicted above that temperature. In the case of steady flow, the low enthalpy change is due to liquid holdup in the annular flow regime, and for pulsating flow, the discrepancy is due to periods of liquid slug flow interrupted by periods of annular flow.|
|Pages:||pp. 609 - 614|
|Keywords:||microcryocooler, mixed refrigerants|
|Research Areas:||Thermophysics, Cryogenics|
|DOI:||http://dx.doi.org/10.1016/j.cryogenics.2012.08.006 (Note: May link to a non-U.S. Government webpage)|
|PDF version:||Click here to retrieve PDF version of paper (1MB)|