STUDY ON THE ISOCHORIC SPECIFIC HEAT CAPACITY OF a R32+R1234ze(E) MIXTURE IN THE LIQUID PHASE

摘要

Isochoric specific heat capacity (c_v) of mass fraction w=0.51 R32+(1-w)trans-1,3,3,3-tetrafluoropropene (R1234ze(E)) mixture in the liquid phase were measured with a twin-cell type adiabatic calorimeter. The sample purity of R32 and R1234ze(E) was certified to have a minimum purity of 0.9997 mole fraction and 0.9996 mole fraction respectively by gas chromatographic analysis. The measurements were obtained for temperatures ranging from 274 K to 464 K and at pressures up to 30 MPa. Temperatures were measured with a platinum resistance thermometer on the bottom of each cell and were reported based on the ITS-90. Sample pressures were measured with a quartz crystal transducer. Densities were calculated from the volume of the calorimeter cell and the sample mass. The expanded uncertainty (with a coverage factor k=2) of temperature measurements is 13 mK, and 8 kPa for pressure measurements. The expanded relative uncertainty of density is 0.16%. As a result, the experimental expanded relative uncertainty of isochoric specific heat capacity (c_v) is estimated to be from 2.02% to 2.75% in the liquid phase. The results of c_v measurements were compared with c_v measurements of the component substances of the mixture which were measured with same calorimeter previously.