models/kchittur/eos-srk.a4c

REQUIRE "thermodynamics.a4l";

IMPORT "johnpye/extpy/extpy";
IMPORT "zplot";
MODEL srk(P WILL_BE pressure;
T WILL_BE temperature;
V WILL_BE molar_volume; 
Z WILL_BE factor; 
data WILL_BE td_component_constants;); 

R IS_A gas_constant;
Pc IS_A pressure;
Tc IS_A temperature;
T_degC IS_A factor;
alpha, beta, q,Tr, Pr, omega IS_A factor;

PSI, OMEGA, sigma, eps IS_A real_constant; 

PSI :== 0.42748; 
OMEGA :== 0.08664; 
sigma :== 1.0; 
eps :== 0.0; 

Pc = data.Pc;
Tc = data.Tc;
omega = data.omega;

eq1: Tr = T/Tc;
eq2: Pr = P/Pc;
eq3: T_degC = T/1{K} - 273.15;

eq4: alpha = (1.0 + (0.480+1.574*omega-0.176*omega^2)*(1.0-Tr^(0.5)))^2;
eq5: q = PSI*alpha/(OMEGA*Tr);
eq6: beta = OMEGA*Pr/Tr;
eq7: Z = 1.0 + beta - q*beta*(Z - beta)/((Z + eps*beta)*(Z + sigma*beta));
eq8: P*V = Z*R*T;


METHODS
    METHOD default_self;
    RUN ClearAll;
    RUN specify;
    RUN values;
    END default_self;

        METHOD specify;
        P.fixed := TRUE;
        T.fixed := TRUE;
        T_degC.fixed := FALSE;
        END specify;
        METHOD values;
        P := 12.0 {bar};
        T := 298.15 {K};
        Z.lower_bound := 0.0;
        Z.upper_bound := 10.0;
        Z.nominal := 1.0;
        END values;

END srk;
MODEL testsrk;

c1 IS_A symbol_constant;
c1 :== 'ethylene';
cd IS_A components_data([c1],c1);
Tr, Pr IS_A factor;
P IS_A pressure;
T IS_A temperature;
V IS_A molar_volume; 
Z IS_A factor; 
tsrk IS_A srk(P,T,V,Z,cd.data[c1]); 

eqTr: Tr = T/cd.data[c1].Tc;
eqPr: Pr = P/cd.data[c1].Pc;

METHODS
    METHOD default_self;
    RUN ClearAll;
    RUN specify;
    RUN values;
    END default_self;

    METHOD specify;
    P.fixed := TRUE;
    V.fixed := FALSE;
    Z.fixed := FALSE;  
    T.fixed := TRUE;
    RUN tsrk.specify;
    END specify;
    METHOD values;
    P := 12.0 {bar};
    T := 298.15 {K};
    RUN tsrk.values;
    END values;

    METHOD on_load;
    RUN default_self;
    END on_load;

    METHOD fancyplot;
    EXTERNAL zplot(SELF);
    END fancyplot;

END testsrk; 
1	REQUIRE "thermodynamics.a4l";
2
3	IMPORT "johnpye/extpy/extpy";
4	IMPORT "zplot";
5	MODEL srk(P WILL_BE pressure;
6	T WILL_BE temperature;
7	V WILL_BE molar_volume;
8	Z WILL_BE factor;
9	data WILL_BE td_component_constants;);
10
11	R IS_A gas_constant;
12	Pc IS_A pressure;
13	Tc IS_A temperature;
14	T_degC IS_A factor;
15	alpha, beta, q,Tr, Pr, omega IS_A factor;
16
17	PSI, OMEGA, sigma, eps IS_A real_constant;
18
19	PSI :== 0.42748;
20	OMEGA :== 0.08664;
21	sigma :== 1.0;
22	eps :== 0.0;
23
24	Pc = data.Pc;
25	Tc = data.Tc;
26	omega = data.omega;
27
28	eq1: Tr = T/Tc;
29	eq2: Pr = P/Pc;
30	eq3: T_degC = T/1{K} - 273.15;
31
32	eq4: alpha = (1.0 + (0.480+1.574omega-0.176omega^2)*(1.0-Tr^(0.5)))^2;
33	eq5: q = PSIalpha/(OMEGATr);
34	eq6: beta = OMEGA*Pr/Tr;
35	eq7: Z = 1.0 + beta - qbeta(Z - beta)/((Z + epsbeta)(Z + sigma*beta));
36	eq8: PV = ZR*T;
37
38
39	METHODS
40	METHOD default_self;
41	RUN ClearAll;
42	RUN specify;
43	RUN values;
44	END default_self;
45
46	METHOD specify;
47	P.fixed := TRUE;
48	T.fixed := TRUE;
49	T_degC.fixed := FALSE;
50	END specify;
51	METHOD values;
52	P := 12.0 {bar};
53	T := 298.15 {K};
54	Z.lower_bound := 0.0;
55	Z.upper_bound := 10.0;
56	Z.nominal := 1.0;
57	END values;
58
59	END srk;
60	MODEL testsrk;
61
62	c1 IS_A symbol_constant;
63	c1 :== 'ethylene';
64	cd IS_A components_data([c1],c1);
65	Tr, Pr IS_A factor;
66	P IS_A pressure;
67	T IS_A temperature;
68	V IS_A molar_volume;
69	Z IS_A factor;
70	tsrk IS_A srk(P,T,V,Z,cd.data[c1]);
71
72	eqTr: Tr = T/cd.data[c1].Tc;
73	eqPr: Pr = P/cd.data[c1].Pc;
74
75	METHODS
76	METHOD default_self;
77	RUN ClearAll;
78	RUN specify;
79	RUN values;
80	END default_self;
81
82	METHOD specify;
83	P.fixed := TRUE;
84	V.fixed := FALSE;
85	Z.fixed := FALSE;
86	T.fixed := TRUE;
87	RUN tsrk.specify;
88	END specify;
89	METHOD values;
90	P := 12.0 {bar};
91	T := 298.15 {K};
92	RUN tsrk.values;
93	END values;
94
95	METHOD on_load;
96	RUN default_self;
97	END on_load;
98
99	METHOD fancyplot;
100	EXTERNAL zplot(SELF);
101	END fancyplot;
102
103	END testsrk;