Thermodynamic properties of 1,1-difluoroethane (R152a) in the critical region

Transport properties of 1,1-difluoroethane (R152a)

“…For the present correlation we have used similar but slightly modified expressions as specified elsewhere [56,57]. The crossover functions depend on the correlation length 4, which for practical purposes is calculated from the dimensionless susceptibility ©¢0,) z*(T'P)= p~, \OPJr (16) where Pc =4.520 MPa is the critical pressure, through an equation of the form [9] (17) Here Go = 1.894 × 10-l°m and F= 0.0487 are the amplitudes of the critical power laws for ~ and Z* [-58] and whose values can be deduced from the asymptotic behavior of the equation of state [6]. Trer is a reference temperature which is chosen in such a way that the critical enhancement of the thermal conductivity tic2 is negligibly small for temperatures greater than Trot; we continued to choose Trer = as previously adapted for R134a [9].…”

“…(10). The various thermodynamic properties in the crossover model were calculated from the equations of state of van Pelt and Sengers [6] and of TillnerRoth [7] as specified in Section 2. Thermal-diffusivity data deduced from dynamic light-scattering measurements have been obtained by Kraft and Leipertz [36] and by Kruppa and Straub [37] for R152a in the critical region.…”

“…An equation for the thermodynamic properties of R152a in the critical region has recently been developed by van Pelt and Sengers [ 6 ] as a supplement to a global equation for the thermodynamic properties of R152a provided by Tillner-Roth [7]. Hence, it is now possible to present equations for the transport properties of R152a over an appreciable range of temperatures and densities including the critical region.…”

Residual properties of gases based on a complete virial equation of state

“…Furthermore, it would be very useful if at least some conclusions for gas mixtures could be deduced from the parametric functions valid for pure fluids. Recent research in this area, reported by Sengers et al [37][38][39][40], looks promising for this purpose.…”

Critical and Crossover Phenomena in Fluids and Fluid Mixtures

“…An extension of the crossover theory by retaining 6 terms in the Landau expansion has been developed [4,13,60], referred to as six-term crossover Landau model. The six-term crossover Landau model (with some minor variations) has been used to represent the thermodynamic properties of a variety of fluids in an appreciable range of temperatures and densities around the critical point including steam [4,67], carbon dioxide [4,68], ethane [4,68,69], methane [69,70], argon [71], sulfur hexafluoride [72], and a number of refrigerants like RI34a [73], R152a [74], and ammonia [75].…”