Reference Correlation for the Viscosity of Cyclopentane from the Triple Point to 460 K and up to 380 MPa

Abstract

This paper presents a new wide-ranging correlation for the viscosity of cyclopentane based on critically evaluated experimental data. The correlation is designed to be used with a recently developed equation of state, and it is valid from the triple point to 360 K in the liquid range up to 380 MPa and 460 K in the low-pressure vapor range. The average absolute percent deviation of the fit for all primary data is 0.8% with a bias of −0.3%. The estimated expanded uncertainty of the whole fit is 2.7% (at the 95% confidence level), while the uncertainty near atmospheric pressure from 298 K to 460 K increases to 4%. The correlation behaves in a physically reasonable manner when extrapolated to 500 MPa; however, care should be taken when using the correlations outside of the validated range.

The NIST REFPROP Database for Highly Accurate Properties of Industrially Important Fluids

“…Other terms could also be added, for example a modified Batchinski-Hildebrand term 139,268,283 or a free-volume type term, 213,284 although these are now generally not used as they can have bad extrapolation behavior at high density. A completely different approach, used for a variety of fluids, 54,63,126,131,201,221,246,248,285 determines the form of the residual contribution using symbolic regression. Symbolic regression is a type of genetic programming that allows the exploration of arbitrary functional forms.…”

“…A completely different approach, used for a variety of fluids, 54 , 63 , 126 , 131 , 201 , 221 , 246 , 248 , 285 determines the form of the residual contribution using symbolic regression. Symbolic regression is a type of genetic programming that allows the exploration of arbitrary functional forms.…”

Reference Correlations of the Viscosity and Thermal Conductivity of 1-Hexene from the Triple Point to High Temperatures and Pressures

“…The viscosity η can be expressed [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] as the sum of four independent contributions, as where ρ is the molar density, T is the absolute temperature, and the first term, η 0 (Τ) = η(0,Τ), is the contribution to the viscosity in the dilute-gas limit, where only two-body molecular interactions occur. The linear-in-density term, η 1 (Τ) ρ, known as the initial density dependence term, can be separately established with the development of the Rainwater-Friend theory [43][44][45] for the transport properties of moderately dense gases.…”

“…In a series of papers published over the last ten years, we reported new reference correlations over extended temperature and pressure ranges, for the viscosity of some simple fluids (xenon [3], water, [4], deuterium oxide [5], ammonia [6]), hydrocarbons (n-hexane [7], n-heptane, [8], n-undecane [9], n-hexadecane [10], benzene [11], toluene [12], cyclopentane [13]), alcohols (methanol [14], ethanol [15], ethane-1,2-diol [16], propane-1,2-diol [17]) and some refrigerants (R-1234yf and R-1234ze(E) [18], R-134a [19], R-161 [20], R-245fa [21], and R-32 [22]).…”

The Temperature Dependence of the Linear-in-Density Thermal Conductivity Coefficient Arising from the Lennard-Jones (12-6) Potential

“…* (𝑇 * ) becomes negative. It has been included with the linear density term in the majority of wide-ranging reference correlations for the viscosity surfaces of fluids which have been developed since 1998 as surveyed by Assael et al [23] as well as in the more recent correlations of Tasidou et al for cyclopentane [24] and of Velliadou et al for xenon [25] and for 1,1,1,2tetrafluoroethane (R134a) [26].…”