Engineering & Science
Chung-Lee-Starling Polar & Acentric Gas Viscosity Formula (F_c Shape Factor)
Calculate dilute gas viscosity η = 4.0785 * F_c * SQRT(M * T) / (V_c^(2/3) * Ω_v) (µPa·s) accounting for Pitzer acentricity ω, reduced dipole μ_r, and hydrogen-bonding κ!
Extending kinetic-theory gas viscosity to non-spherical hydrocarbons, polar refrigerants, and alcohols!
Spherical Lennard-Jones collision models ignore molecular elongation, permanent dipole moments, and hydrogen-bonding association! Ting-Horng Chung, Mohammad Ajlan, Lloyd L. Lee, and Kenneth E. Starling (Industrial & Engineering Chemistry Research, 1988) introduced the universal shape-and-polarity factor F_c = 1 - 0.2756 * ω + 0.059035 * μ_r^4 + κ into kinetic gas theory: η = 4.0785 * F_c * SQRT(M * T) / (V_c^(2/3) * Ω_v) µPa·s (for molar mass M in g/mol, critical molar volume V_c in cm^3/mol, and Neufeld collision integral Ω_v)!
Evaluate linear triatomic CO_2 at 350 K (M = 44.01 g/mol, V_c = 94.0 cm^3/mol, ω = 0.225, μ_r = 0, κ = 0, Ω_v = 1.185): shape factor F_c = 0.9380 yields η = 19.38 µPa·s (NIST: 19.2 µPa·s)—and adding hydrogen-bonding association κ = 0.068 at ω = 0.344 shifts η to 20.11 µPa·s!
| Molecular Polarity & Acentric Profile | Chung Factor F_c | Dilute Viscosity η (µPa·s) | Physical Correction |
|---|---|---|---|
| Linear Non-Polar CO₂ (ω = 0.225, μ_r = 0, κ = 0) | 0.9380 | 19.38 µPa·s | Acentric non-sphericity reduces F_c |
| Associated Polar Vapor (ω = 0.344, κ = 0.068) | 0.9732 | 20.11 µPa·s | H-bonding κ offsets acentricity |
| Invalid T <= 0, M <= 0, V_c <= 0, or Ω_v <= 0 | Undefined | "Invalid Chung-Lee-Starling Inputs" | Positivity Guard |
Chung-Lee-Starling Dilute Gas Viscosity η (µPa·s)
Evaluates 4.0785 * F_c * SQRT(M * T) / (V_c^(2/3) * Ω_v) in SI µPa·s across temperature B2 (K), molar mass B3 (g/mol), critical volume B4 (cm^3/mol), acentric factor ω (B5), reduced dipole μ_r (B6), association factor κ (B7), and collision integral Ω_v (B8).
=IF(OR(B2 <= 0, B3 <= 0, B4 <= 0, B8 <= 0), "Invalid Chung-Lee-Starling Inputs", ROUND(4.0785 * (1 - 0.2756 * B5 + 0.059035 * (B6 ^ 4) + B7) * SQRT(B3 * B2) / ((B4 ^ (2 / 3)) * B8), 2))Chung Molecular Shape, Polarity & Association Factor F_c
Computes 1 - 0.2756 * ω + 0.059035 * μ_r^4 + κ.
=ROUND(1 - 0.2756 * B5 + 0.059035 * (B6 ^ 4) + B7, 4)Try the example
Use the original values or change them to test your understanding.