Measurement and correlation of the (pressure, density, temperature) relation of nitrogen in the temperature range from 273.15 to 323.15 K at pressures up to 8 MPa

Apparatus for accurate density measurements of fluids based on a magnetic suspension balance

“…Our data agree well with the literature data, and they exhibit considerably less scatter than the data of Ben et al [11] and Ejaz S. [12]. Ben et al [11]; +, Duschek et al [8]; ×,Nowak et al [9]; ,Ejaz S. [12].…”

“…FIGURE 4 shows the comparison of the present experimental results with the literature data which overlap our temperature and pressure range. The data from Duschek et al [8] and Nowak et al [9] were measured by a two-sinker densimeter, and were used to fit the equation of Span et al [7]. The literature data [12] were measured by a single-sinker densimeter.…”

Measurement and correlation of the (p,ρ,T) relation of nitrogen. I. The homogeneous gas and liquid regions in the temperature range from 66 K to 340 K at pressures up to 12 MPa

“…A detailed comparison of the new (p, r, T ) values with several selected measurements of other workers (14,(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34) is presented on 12 representative isotherms outside the critical region in figures 2 to 5 (relative deviation in density) and on three isotherms in the critical region in figure 6 (relative deviation in pressure). The figures show the deviations between measured values and values calculated from a preliminary equation of state, which was established only for comparison purposes and was fitted only to the new measurements.…”

“…In addition to the experimental results, the figures also contain plots of values calculated from two equations of state; one was published in the IUPAC book on nitrogen (35) and the other in Jacobsen et al (36) The first temperature value given above each diagram corresponds to our measurements and the temperature range written in brackets covers the results of the other authors. A summary of the selected sets of measurements (14,(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34) together with their uncertainties is listed in table 3. In order to avoid overcrowding of the diagrams in the case of very comprehensive sets of measurements some of the measuring points have been omitted, however, without losing any essential information.…”

“…This densimeter was developed in order to obtain accurate (p, r, T ) measurements of pure fluids in the homogeneous gas and liquid phase including the critical region and, in particular, the entire (vapour + liquid) coexistence curve. Up to now, comprehensive measurements on methane, (3)(4)(5)(6) carbon dioxide, (7)(8)(9) argon, (10,11) and ethylene (12,13) have been carried out successfully; nitrogen, (14) sulphur hexafluoride, (15) and the refrigerants R12 and R22 (16) have been measured in parts of the fluid region. The design of the densimeter was described in detail in previous papers; (3,6) therefore only the measuring principle is briefly explained here.…”