Tc = pcsaft_tc(m,ϵ)

Returns the critical temperature of the PCSAFT equation of state.

Inputs:

• m: Segment length (no units)
• ϵ: Reduced interaction energy [K]

Outputs:

• Tc : Critical Temperature [K]. Returns NaN if the value is outside the range of the ancillary (1 ≤ m ≤ 64).

Examples

julia> m, ϵ = 1.0, 150.03 #values for methane
(1.0, 150.03)

julia> Tc = pcsaft_tc(m, ϵ)
191.40058128833536

rhoc = pcsaft_rhoc(m,σ)

Returns the critical density of the PCSAFT equation of state.

Inputs:

• m: Segment length (no units)
• σ: Monomer diameter [m]

Outputs:

• rhoc : Critical density [mol/m^3]. Returns NaN if the value is outside the range of the ancillary (1 ≤ m ≤ 64).

vc = pcsaft_vc(m,σ)

Returns the critical volume of the PCSAFT equation of state. Equal to 1/pcsaft_rhoc(m,ϵ,σ)

Inputs:

• m: Segment length (no units)
• σ: Monomer diameter [m]

Outputs:

• vc : Critical volume [m^3/mol]. Returns NaN if the value is outside the range of the ancillary (1 ≤ m ≤ 64).

rhol,rhov = pcsaft_rhosat(T,m,ϵ,σ)

Returns the saturation densities of the PCSAFT equation of state at the input temperature T.

Inputs:

• T: Saturation temperature (Kelvin)
• m: Segment length (no units)
• ϵ: Reduced interaction energy [K]
• σ: Monomer diameter [m]

Outputs:

• rhol : saturation liquid density [mol/m^3].
• rhov : saturation vapour density [mol/m^3].

Returns NaN,NaN if the value is outside the range of the ancillary (1 ≤ m ≤ 64 and Tmin < T < Tc).

vl,vv = pcsaft_vsat(T,m,ϵ,σ)

Returns the saturation volumes of the PCSAFT equation of state at the input temperature T.

Inputs:

• T: Saturation temperature (Kelvin)
• m: Segment length (no units)
• ϵ: Reduced interaction energy [K]
• σ: Monomer diameter [m]

Outputs:

• vl : saturation liquid volume [m^3/mol].
• vv : saturation vapour volume [m^3/mol].

Returns NaN,NaN if the value is outside the range of the ancillary (1 ≤ m ≤ 64 and Tmin < T < Tc).

vv = pcsaft_vvsat(T,m,ϵ,σ)

Returns the saturation vapour volume of the PCSAFT equation of state at the input temperature T.

Inputs:

• T: Saturation temperature (Kelvin)
• m: Segment length (no units)
• ϵ: Reduced interaction energy [K]
• σ: Monomer diameter [m]

Outputs:

• vl : saturation liquid volume [m^3/mol].

Returns NaN if the value is outside the range of the ancillary (1 ≤ m ≤ 64 and Tmin < T < Tc).

vl = pcsaft_vlsat(T,m,ϵ,σ)

Returns the saturation liquid volume of the PCSAFT equation of state at the input temperature T.

Inputs:

• T: Saturation temperature (Kelvin)
• m: Segment length (no units)
• ϵ: Reduced interaction energy [K]
• σ: Monomer diameter [m]

Outputs:

• vl : saturation liquid volume [m^3/mol].

Returns NaN if the value is outside the range of the ancillary (1 ≤ m ≤ 64 and Tmin < T < Tc).

Θ,status = pcsaft_theta(T̃,m)
Θ,status = pcsaft_theta(T̃,m,T̃c)

Calculates reduced scaled temperature parameter used in PCSAFT saturation volume superancillary

Inputs:

• T̃: Temperature divided by reduced interaction energy (T/ϵ) (no units)
• m: Segment length (no units)
• T̃c: (Optional) Reduced critical temperature (Tc/ϵ) (no units)

Outputs:

• Θ : scaled temperature parameter (no units)

• status : Symbol used to signal if the combination of T̃,m is valid or not. It can return one of the following:

  • :inrange : if the combination is valid
  • :nonfinite : if any input is not finite
  • :below_mmin : if m < 1.0
  • :over_mmax : if m > 64.0
  • :below_Tmin : if T̃ < T̃min, where T̃min = T̃c*exp(-2.20078778)*m^0.37627892
  • :over_Tmax : if T̃ > T̃c

ρ̃l,ρ̃v = pcsaft_rhosat_reduced(Θ,m)

Calculates the reduced saturation densities. The actual densities are calculated as ρᵢ = ρ̃ᵢ/(N_A*σ^3)

Inputs:

• Θ: reduced temperature parameter (no units)
• m: Segment length (no units)

Outputs:

• ρ̃l : reduced saturation liquid density (no units)
• ρ̃v : reduced saturation vapour density (no units)

Returns NaN if the value is outside the range of the ancillary (1 ≤ m ≤ 64 and 0 < Θ < 1).

ρ̃l = pcsaft_rholsat_reduced(Θ,m)

Calculates the reduced liquid saturation density. The actual density is ρ = ρ̃/(N_A*σ^3)

Inputs:

• Θ: reduced temperature parameter (no units)
• m: Segment length (no units)

Outputs:

• ρ̃l : reduced saturation liquid density (no units)

Returns NaN if the value is outside the range of the ancillary (1 ≤ m ≤ 64 and 0 < Θ < 1).

ρ̃v = pcsaft_rhovsat_reduced(Θ,m)

Calculates the reduced vapour saturation density. The actual density is ρ = ρ̃/(N_A*σ^3)

Inputs:

• Θ: reduced temperature parameter (no units)
• m: Segment length (no units)

Outputs:

• ρ̃v : reduced saturation vapour density (no units)

Returns NaN if the value is outside the range of the ancillary (1 ≤ m ≤ 64 and 0 < Θ < 1).

ω = pcsaft_acentric(m)

Returns the acentric factor of the PCSAFT equation of state.

Inputs:

• m: Segment length (no units)

Outputs:

• ω : acentric factor (no units). Returns NaN if the value is outside the range of the ancillary (1 ≤ m ≤ 64).

Examples

julia> m = 1.0
(1.0, 150.03)

julia> Tc = pcsaft_acentric(m)
191.40058128833536

m = pcsaft_m_from_acentric(w)

Given the acentric factor of a component, returns the segment length that corresponds to the real acentric factor calculated by the PCSAFT equation of state.

Inputs:

• ω : acentric factor (no units)

Outputs:

• m: Segment length (no units). Returns NaN if the value is outside the range of the ancillary (0.005073686089814064 ≤ w ≤ 6.0465684112508296).