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D2779-92 – Standard Test Method Technical Guide
ASTM D2779-92 (Reapproved 2020) provides a standardized method for estimating the equilibrium solubility of common aerospace gases in hydrocarbon liquids. By integrating fundamental thermodynamic equations with empirically established constants, this test method offers a practical approach for engineering calculations across a wide range of temperatures and liquid densities.
🎯 Scope and Application
This test method is designed for estimating the solubility of gases encountered in the aerospace industry in petroleum liquids. It applies to petroleum fractions with densities ranging from 0.63 to 0.90 kg/L at 288 K (59°F). The estimation is valid over a temperature range of 228 K (−50°F) to 423 K (302°F).
The methodology is fundamentally based on the Clausius-Clapeyron equation, Henry’s law, and the perfect gas law. Empirically assigned constants are incorporated to account for the variation in solubility with liquid density and for the specific characteristics of each gas. Values are stated in SI units as the standard.
📐 Key Terminology and Symbols
The standard defines critical solubility coefficients and thermodynamic variables necessary for successful application.
| 🔣 Symbol | 📖 Definition | 📏 Unit / Context |
|---|---|---|
| d | Density of the liquid at 288 K (59°F) | kg/L |
| T | Specified temperature | K |
| Lₒ | Ostwald coefficient at 273 K for a liquid of d=0.85 | — |
| L | Ostwald coefficient at T for a liquid of d=0.85 | — |
| Lc | Ostwald coefficient at T for the specified liquid density | — |
| p | Pressure of the gas or mixed gases | MPa |
| pv | Vapor pressure of the liquid at temperature T |