Joule–Thomson Coefficient Calculator
Estimate the Joule–Thomson coefficient μ = (2a/RT − b)/Cp for a van der Waals gas.
Input Data
Vdw A
Pa·m⁶/mol²
Vdw B
m³/mol
Temperature K
K
Molar Heat Capacity Cp
J/(mol·K)
Results
μ = (2a/(RT) − b)/Cp.
0.000002445K/Pa
T_inv = 2a/(Rb).
851.540705K
μ>0 cools on expansion.
1
At a glance:μ_JT ≈ (2a/(RT) − b)/Cp; inversion T = 2a/(Rb). Complements throttling and van-der-waals.
Formula
μ = (2a/(R·T) − b)/Cp.
$$\mu_{JT} = \frac{1}{C_p}\left(\frac{2a}{RT} - b\right), \quad T_{inv} = \frac{2a}{Rb}, \quad \Delta T = \mu_{JT} \cdot \Delta P$$How to Use
- Enter a, b, T and Cp.
- The tool returns μ and inversion T.
Case Studies
N₂-like a,b, T=300
μ ≈ 0.2 K/bar (cools).
FAQ
Cooling or heating?
μ>0 → cooling on expansion (below inversion T); μ<0 → heating.
Related Tools
References
Content review: Calculatorism Science Team. Results are for reference only; please refer to the relevant authorities for the official figures.