dc51bf9c-5d91-4483-895d-2b2e06c4b607 89 Alvaro Diaz Falconi 4 5 false false 0 10 decimal

Fluids ETHANE METHANE PROPANE stack :

n Fluids length :

x 0.5 0.3 0.2 stack :

x sum 1

Mix :

i 1 n range Mix Mix & Fluids i el [x i el var2str] concat : for

Mix Mix 2 substr : ETHANE[0.5]&METHANE[0.3]&PROPANE[0.2]

To 600 K * :

Po 150 kPa * :

Objective: find Vo @ To, Po using Redlich-Kwong

Tc TCRIT Fluids CoolProp_Props1 vectorize : K 305.322 190.564 369.89 31 mat

Critical properties

Pc PCRIT Fluids CoolProp_Props1 vectorize : MPa 4.8722 4.5992 4.2512 31 mat

b 23 nthroot 1 - 3 / mol K * J / * R.m 2^* Tc Pc / * vectorize : L mol / 0.3753 0.2482 0.5211 31 mat

volume constant correction for each compound

b' x i el b i el * i 1 n sum : L mol / 0.3663

volume constant correction for the mixture. Notice that it is lineal in x

a 1923 nthroot 1 - (* / R.m 2^* Tc 2.5^Pc / * vectorize : J 2^K sqrt * mol 2^Pa * / 9.88 3.2211 18.2918 31 mat

attractive potential of molecules coefficient for each compound

i 1 n range j 1 n range α i j el a i el a j el * sqrt : for for

α J 2^K sqrt * mol 2^Pa * / 9.88 5.6413 13.4433 5.6413 3.2211 7.6759 13.4433 7.6759 18.2918 33 mat

The "a" coefficient for the mixture is not lineal in x, assuming that α(i,j) is the geometric mean of a(i) & a(j)

a' x i el x j el * α i j el * j 1 n sum i 1 n sum : J 2^K sqrt * mol 2^Pa * / 8.7937

attractive potential of molecules coefficient for the mixture

Now we can solve the Redlich-Kwong for the mixture like it was a compound

Vo Po R.m To * Vo b' - / a' To sqrt Vo * Vo b' + (* / - ≡ Vo 1 L mol / * ≡ FindRoot :

Vo L mol / 33.5544

Coolprop result:

M Mix CoolProp_Props1 D T To P Po Mix CoolProp_Props / L mol / 33.2394

Alvaro

4 appVersion 1.0.8348.30405