Cantera 2.6.0

Methane.cpp
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1//! @file Methane.cpp
2
3// This file is part of Cantera. See License.txt in the top-level directory or
4// at https://cantera.org/license.txt for license and copyright information.
5
6#include "Methane.h"
7#include "cantera/base/stringUtils.h"
8
9 using namespace std;
10 using namespace Cantera;
11
12 namespace tpx
13{
14 static const double
15M = 16.04996,
16Tmn = 90.68,
17Tmx = 1700.0,
18Tc = 190.555,
19Pc = 4.5988e6,
20Roc= 160.43,
21Tt = 90.68,
22Pt=11743.5675,
23R = 5.18253475866e2,
24Gamma=3.72992471469e-5,
25alpha = 1.5, //Used with Psat
26alpha1 = .36, //used with ldens;
27Rot=451.562,
28beta=2009.152,
29u0 = 357696.0858,
30s0 = -1918.035071;
31
32 static const double Ameth[] = {
33 -7.25929210183, 4.13766054566e2, -6.32167316855e3,
34 3.34015577724e5, -1.68253379982e7, 1.87884851902e-2, -1.18673201223e1,
35 2.09062618015e3, -4.07532656958e5, -5.73917603241e-5,4.37711441593e-2,
36 -4.38766500673, 1.13524630779e-5, -5.07028240949e-5, 2.28002199522e-2,
37 9.25611329590e-9, 1.33865662546e-10, -1.65439044196e-7, 1.81030980110e-10,
38 5.45753645958e5, -3.63192281933e7, 4.81463473761, 1.56633022620e5,
39 7.89977010972e-5, 1.39993881210e-2, -1.70656092212e-11, -4.55256623445e-5,
40 -2.29314170748e-14,8.31548197665e-12, 6.84673626259e-20,
41 -4.70845544152e-17, 5.21465091383e-16
42};
43
44 static const double Dmeth[]=
45{ -1.78860165e-1, 4.83847500e-2, -1.84898700e-2 };
46
47 static const double Fmeth[]=
48{ 4.77748580, 1.76065363, -5.67888940e-1, 1.32786231 };
49
50 static const double Gmeth[]=
51{ 1.34740610e3, 1.35512060e2, -2.93910458e1, 2.12774600, 2.44656600e3 };
52
53 double methane::C(int i, double rt, double rt2)
54{
55 switch (i) {
56 case 0:
57 return Ameth[0] * T + Ameth[1] * sqrt(T) + Ameth[2] + (Ameth[3] + Ameth[4] * rt) * rt;
58 case 1:
59 return Ameth[5] * T + Ameth[6] + rt * (Ameth[7] + Ameth[8] * rt);
60 case 2:
61 return Ameth[9] * T + Ameth[10] + Ameth[11] * rt;
62 case 3:
63 return Ameth[12];
64 case 4:
65 return rt*(Ameth[13] + Ameth[14]*rt);
66 case 5:
67 return Ameth[15]*rt;
68 case 6:
69 return rt*(Ameth[16] + Ameth[17]*rt);
70 case 7:
71 return Ameth[18]*rt2;
72 case 8:
73 return rt2*(Ameth[19] + Ameth[20]*rt);
74 case 9:
75 return rt2*(Ameth[21] + Ameth[22]*rt2);
76 case 10:
77 return rt2*(Ameth[23] + Ameth[24]*rt);
78 case 11:
79 return rt2*(Ameth[25] + Ameth[26]*rt2);
80 case 12:
81 return rt2*(Ameth[27] + Ameth[28]*rt);
82 case 13:
83 return rt2*(Ameth[29] + Ameth[30]*rt + Ameth[31]*rt2);
84 default:
85 return 0.0;
86 }
87}
88
89 double methane::Cprime(int i, double rt, double rt2, double rt3)
90{
91 switch (i) {
92 case 0:
93 return Ameth[0] + 0.5*Ameth[1]/sqrt(T) - (Ameth[3] + 2.0*Ameth[4]*rt)*rt2;
94 case 1:
95 return Ameth[5] - rt2*(Ameth[7] + 2.0*Ameth[8]*rt);
96 case 2:
97 return Ameth[9] - Ameth[11]*rt2;
98 case 3:
99 return 0.0;
100 case 4:
101 return -rt2*(Ameth[13] + 2.0*Ameth[14]*rt);
102 case 5:
103 return -Ameth[15]*rt2;
104 case 6:
105 return -rt2*(Ameth[16] + 2.0*Ameth[17]*rt);
106 case 7:
107 return -2.0*Ameth[18]*rt3;
108 case 8:
109 return -rt3*(2.0*Ameth[19] + 3.0*Ameth[20]*rt);
110 case 9:
111 return -rt3*(2.0*Ameth[21] + 4.0*Ameth[22]*rt2);
112 case 10:
113 return -rt3*(2.0*Ameth[23] + 3.0*Ameth[24]*rt);
114 case 11:
115 return -rt3*(2.0*Ameth[25] + 4.0*Ameth[26]*rt2);
116 case 12:
117 return -rt3*(2.0*Ameth[27] + 3.0*Ameth[28]*rt);
118 case 13:
119 return -rt3*(2.0*Ameth[29] + 3.0*Ameth[30]*rt + 4.0*Ameth[31]*rt2);
120 default:
121 return 0.0;
122 }
123}
124
125 double methane::W(int n, double egrho)
126{
127 return (n == 0 ? (1.0 - egrho)/(2.0*Gamma) :
128 (n*W(n-1, egrho) - 0.5*pow(Rho,2*n)*egrho)/Gamma);
129}
130
131 double methane::H(int i, double egrho)
132{
133 return (i < 8 ? pow(Rho,i+2) : pow(Rho,2*i-13)*egrho);
134}
135
136 double methane::I(int i, double egrho)
137{
138 return (i < 8 ? pow(Rho,i+1)/double(i+1) : W(i-8, egrho));
139}
140
141 double methane::up()
142{
143 double rt = 1.0/T;
144 double rt2 = rt*rt;
145 double rt3 = rt*rt2;
146 double egrho = exp(-Gamma*Rho*Rho);
147 double t3 = pow(T,1.0/3.0);
148
149 double sum = 0.0;
150 for (int i=0; i<14; i++) {
151 sum += (C(i, rt, rt2) - T*Cprime(i, rt, rt2, rt3))*I(i, egrho);
152 }
153 sum += T*(Gmeth[0] + 0.75*Gmeth[1]*t3 + 0.6*Gmeth[2]*t3*t3 + 0.5*Gmeth[3]*T)
154 + Gmeth[4]*beta/(exp(beta*rt) - 1.0) + u0;
155 return sum + m_energy_offset;
156}
157
158 double methane::sp()
159{
160 double rt = 1.0/T;
161 double rt2 = rt*rt;
162 double rt3 = rt*rt2;
163 double egrho = exp(-Gamma*Rho*Rho);
164 double t3 = pow(T,1.0/3.0);
165 double sum = 0.0;
166 sum = s0 - R*log(Rho);
167 for (int i=0; i<14; i++) {
168 sum -= Cprime(i, rt, rt2, rt3)*I(i, egrho);
169 }
170 sum += Gmeth[0]*log(T) + 3.0*Gmeth[1]*t3 + 1.5*Gmeth[2]*t3*t3 + Gmeth[3]*T
171 + Gmeth[4]*(beta*rt + beta*rt/(exp(beta*rt) - 1.0)
172 - log(exp(beta*rt) - 1.0));
173 return sum + m_entropy_offset;
174}
175
176 double methane::Pp()
177{
178 double rt = 1.0/T;
179 double rt2 = rt*rt;
180 double egrho = exp(-Gamma*Rho*Rho);
181
182 double P = Rho*R*T;
183 for (int i=0; i<14; i++) {
184 P += C(i, rt, rt2)*H(i, egrho);
185 }
186 return P;
187}
188
189 double methane::Psat()
190{
191 double x = (1.0 - Tt/T)/(1.0 - Tt/Tc);
192 double result;
193 if ((T < Tmn) || (T > Tc)) {
194 throw CanteraError("methane::Psat",
195 "Temperature out of range. T = {}", T);
196 }
197 result = Fmeth[0]*x + Fmeth[1]*x*x + Fmeth[2]*x*x*x +
198 Fmeth[3]*x*pow(1-x, alpha);
199 return exp(result)*Pt;
200}
201
202 double methane::ldens()
203{
204 double result;
205 double sum;
206 double w;
207 if ((T < Tmn) || (T > Tc)) {
208 throw CanteraError("methane::ldens",
209 "Temperature out of range. T = {}", T);
210 }
211 w = (Tc - T)/(Tc - Tt);
212 sum = Dmeth[0]*(1.0 - pow(w, 2.0/3.0)) + Dmeth[1]*(1.0 - pow(w, 4.0/3.0))
213 + Dmeth[2]*(1.0 - pow(w, 2));
214 result = pow(w,alpha1)*exp(sum);
215 result *= (Rot-Roc);
216 result += Roc;
217 return result;
218}
219
220 double methane::Tcrit()
221{
222 return Tc;
223}
224 double methane::Pcrit()
225{
226 return Pc;
227}
228 double methane::Vcrit()
229{
230 return 1.0/Roc;
231}
232 double methane::Tmin()
233{
234 return Tmn;
235}
236 double methane::Tmax()
237{
238 return Tmx;
239}
240 double methane::MolWt()
241{
242 return M;
243}
244
245}
Methane.h
Cantera::CanteraError
Base class for exceptions thrown by Cantera classes.
Definition: ctexceptions.h:61
tpx::Substance::x
double x()
Vapor mass fraction.
Definition: Sub.cpp:275
tpx::Substance::P
double P()
Pressure [Pa].
Definition: Sub.cpp:48
tpx::methane::Vcrit
double Vcrit()
Critical specific volume [m^3/kg].
Definition: Methane.cpp:228
tpx::methane::Tmax
double Tmax()
Maximum temperature for which the equation of state is valid.
Definition: Methane.cpp:236
tpx::methane::Tmin
double Tmin()
Minimum temperature for which the equation of state is valid.
Definition: Methane.cpp:232
tpx::methane::MolWt
double MolWt()
Molecular weight [kg/kmol].
Definition: Methane.cpp:240
tpx::methane::sp
double sp()
Entropy of a single-phase state.
Definition: Methane.cpp:158
tpx::methane::Tcrit
double Tcrit()
Critical temperature [K].
Definition: Methane.cpp:220
tpx::methane::Pcrit
double Pcrit()
Critical pressure [Pa].
Definition: Methane.cpp:224
tpx::methane::Psat
double Psat()
Saturation pressure. Equation S3 from Reynolds TPSI.
Definition: Methane.cpp:189
tpx::methane::ldens
double ldens()
Liquid density. Equation D3 from Reynolds TPSI.
Definition: Methane.cpp:202
tpx::methane::up
double up()
Internal energy of a single-phase state.
Definition: Methane.cpp:141
Cantera
Namespace for the Cantera kernel.
Definition: AnyMap.cpp:557
stringUtils.h
Contains declarations for string manipulation functions within Cantera.