Thermodynamics Overview

Jasper's thermodynamic engine calculates physical properties required for process simulation.

Capabilities

Property	Method	Status
Heat capacity (Cp)	Polynomial correlation	Implemented
Enthalpy	Integration of Cp	Implemented
Vapor pressure	Antoine equation	Implemented
VLE	Raoult's Law	Implemented
Density	Ideal gas / liquid correlations	Partial

Property Calculation Flow

Component Data (MW, Tc, Pc, Cp coefficients, Antoine coefficients)
         │
         ▼
┌─────────────────┐
│  Heat Capacity  │  →  Cp(T) = a + bT + cT² + dT³
└─────────────────┘
         │
         ▼
┌─────────────────┐
│    Enthalpy     │  →  H(T) = ∫Cp dT + Hf
└─────────────────┘
         │
         ▼
┌─────────────────┐
│ Vapor Pressure  │  →  log(Psat) = A - B/(T+C)
└─────────────────┘
         │
         ▼
┌─────────────────┐
│      VLE        │  →  Ki = Psat,i / P
└─────────────────┘

Rigorous Mode (IDAES)

When rigorous mode is selected, Jasper delegates thermodynamic calculations to the IDAES framework. This provides equation-oriented solving with a choice of property packages:

Property Package	Type	Best For
Ideal	Activity coefficient (gamma = 1)	Ideal mixtures, experiment comparison
SRK	Cubic EOS	Hydrocarbon systems, gas processing
PR (Peng-Robinson)	Cubic EOS	General-purpose, hydrocarbon VLE
NRTL	Activity coefficient	Polar / non-ideal liquid mixtures
UNIQUAC	Activity coefficient	Strongly non-ideal liquids, LLE
eNRTL	Electrolyte activity coefficient	Electrolyte and amine systems

For a detailed guide on selecting and configuring property packages, see Property Packages.

Assumptions

Quick mode assumptions (these do not apply to rigorous mode):

• Ideal gas behavior for vapor phase
• Ideal liquid solutions (Raoult's Law)
• No solid phases

Planned improvements (Quick mode):

• Steam tables (IAPWS-IF97)

tip

Peng-Robinson and SRK equations of state, as well as NRTL and UNIQUAC activity coefficient models, are already available in rigorous mode.

Units

All internal calculations use SI units:

Property	Internal Unit
Temperature	K
Pressure	Pa
Flow	mol/s
Enthalpy	J/mol
Heat capacity	J/(mol·K)