Hot-Wire Measurements of the Thermal Conductivity of RE347mcc and Novec 649
Measurements of thermal conductivity are reported for 1,1,1,2,2,3,3-heptafluoro-3-methoxypropane (RE347mcc, HFE-7000 and Novec 7000) and 1,1,1,2,2,4,5,5,5-nonafluoro-4-(trifluoromethyl)-3-pentanone (Novec 649, FK-5-1-12 and Novec 1230). These two fluids are of interest as working fluids for organic Rankine power cycles with low global-warming potentials and near-zero ozone depletion potentials. Thermal conductivity data are reported for both fluids at temperatures from near their triple points up to 500 K in the liquid, vapor and supercritical phases at pressures up to 70 MPa. The measurements were made with two hot-wire apparatus with platinum wires of 12.7 micron diameter. The measurements were made with the steady-state technique for gas at pressures below 1 MPa, while the transient technique was used for liquid and supercritical gas at pressures above 1 MPa. The low-temperature apparatus was used at temperatures from 160 K to 340 K, while the high-temperature apparatus was used at temperatures above 340 K. Comparisons with preliminary correlations are shown. The thermal conductivity data in the critical region show contributions from the thermal conductivity critical enhancement. The critical enhancement for the thermal conductivity of this fluid is consistent with mode-coupling theory that indicates the thermal conductivity of a pure fluid is divergent at the critical point.
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Richard Perkins (POC,Primary Presenter,Co-Author), NIST Applied Chemicals and Materials Division, email@example.com;
Marcia Huber (Co-Author), NIST Applied Chemicals and Materials Division, firstname.lastname@example.org;