136 lines
4 KiB
C++
Executable file
136 lines
4 KiB
C++
Executable file
// Lee-Kesler equation of state
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#include "lk.h"
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#include <math.h>
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namespace tpx {
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static double b[2][4] = {{0.1181193, 0.265728, 0.154790, 0.030323},
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{0.2026579, 0.331511, 0.027655, 0.203488}};
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static double c[2][4] = {{0.0236744, 0.0186984, 0.0, 0.042724},
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{0.0313385, 0.0503618, 0.016901, 0.041577}};
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static double d[2][2] = {{1.55488e-5, 6.23689e-5},{4.8736e-5, 0.740336e-5}};
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static double beta[2] = {0.65392, 1.226};
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static double gamma[2] = {0.060167, 0.03754};
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//--------------------------- member functions ------------------
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double leekesler::W(int n, double egrho, double Gamma) {
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return (n == 0 ? (1.0 - egrho)/(2.0*Gamma) :
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(n*W(n-1, egrho, Gamma) - 0.5*pow(Rho,2*n)*egrho)/Gamma);
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}
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double leekesler::up(){
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return -(8314.3/Mw)*T*(1.0 + T*I()/Tcr); // + h_0(T)
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}
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double leekesler::hdep(){
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double tr = T/Tcr;
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return tr*tr*I() + (1.0 - z())*tr;
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}
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double leekesler::sdep(){
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double tr = T/Tcr;
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return tr*I() + J() - log(z());
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}
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double leekesler::sp() {
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const double Pref = 101325.0;
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double rgas = 8314.3/Mw;
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return rgas*(log(Pref/(Rho*rgas*T)) - (T/Tcr)*I() - J());
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}
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double leekesler::I() { // \int_0^\rho_r (1/\rho_r)(dZ/dT_r) d\rho_r
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double Bp, Cp, Dp;
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double rtr = Tcr/T;
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double rtr2 = rtr*rtr;
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double rvr = 8314.3*Tcr*Rho/(Pcr*Mw); // 1/v_r^\prime
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double rvr2 = rvr*rvr;
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double egrho;
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egrho = exp(-gamma[Isr]*rvr2);
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Bp = rtr2*b[Isr][1] + 2.0*rtr*rtr2*b[Isr][2] + 3.0*rtr2*rtr2*b[Isr][3];
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Cp = rtr2*c[Isr][1] - 3.0*c[Isr][2]*rtr2*rtr2;
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Dp = -d[Isr][1]*rtr2;
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double r = Bp*rvr + 0.5*rvr2*Cp + 0.2*pow(rvr,5)*Dp
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- 3.0*c[Isr][3]*rtr2*rtr2*(beta[Isr]*W(0,egrho,gamma[Isr])
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+ gamma[Isr]*W(1,egrho,gamma[Isr]));
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return r;
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}
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double leekesler::J() { // \int_0^\rho_r (1/\rho_r)(Z - 1) d\rho_r
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double BB, CC, DD;
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double rtr = Tcr/T;
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double rtr2 = rtr*rtr;
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double rvr = 8314.3*Tcr*Rho/(Pcr*Mw); // 1/v_r^\prime
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double rvr2 = rvr*rvr;
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double egrho;
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egrho = exp(-gamma[Isr]*rvr2);
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BB = b[Isr][0] - rtr*(b[Isr][1]
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+ rtr*(b[Isr][2] + rtr*b[Isr][3]));
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CC = c[Isr][0] - rtr*(c[Isr][1] - c[Isr][2]*rtr*rtr);
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DD = d[Isr][0] + d[Isr][1]*rtr;
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double r = BB*rvr + 0.5*rvr2*CC + 0.2*pow(rvr,5)*DD
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+ c[Isr][3]*rtr2*rtr*(beta[Isr]*W(0,egrho,gamma[Isr])
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+ gamma[Isr]*W(1,egrho,gamma[Isr]));
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return r;
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}
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double leekesler::z() {
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double zz, rvr2, BB, CC, DD, EE;
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double rtr = Tcr/T; // 1/T_r
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double rvr = Rho*8314.3*Tcr/(Pcr*Mw);
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rvr2 = rvr*rvr;
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BB = b[Isr][0] - rtr*(b[Isr][1]
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+ rtr*(b[Isr][2] + rtr*b[Isr][3]));
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CC = c[Isr][0] - rtr*(c[Isr][1] - c[Isr][2]*rtr*rtr);
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DD = d[Isr][0] + d[Isr][1]*rtr;
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EE = exp(-gamma[Isr]*rvr2);
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zz = 1.0 + BB*rvr + CC*rvr2 + DD*pow(rvr,5)
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+ c[Isr][3]*pow(rtr,3)*rvr2*
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(beta[Isr] + gamma[Isr]*rvr2)*EE;
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return zz;
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}
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double leekesler::Pp() {
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return 8314.3*z()*Rho*T/Mw;
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}
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double leekesler::Psat(){
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double tr = 1.0 - Tcr/T;
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double lpr;
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if (Isr == 0)
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lpr = 5.395743797*tr + 0.05524287*tr*tr + 0.06853005*tr*tr*tr;
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else
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lpr = 7.259961465*tr - 0.549206092*tr*tr + 0.177581752*tr*tr*tr;
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return Pcr*exp(lpr);
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}
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double leekesler::ldens(){
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double x = 1.0 - T/Tcr;
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// for simple fluid
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double rho_r;
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if (Isr == 0)
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rho_r = 5.2307 + 15.16*x - 21.9778*x*x + 18.767*x*x*x;
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else {
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rho_r = 6.166930606 + 17.42866964*x - 18.62589833*x*x
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+ 11.73957224*x*x*x;
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rho_r *= 1.0;
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}
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return Pcr*rho_r*Mw/(8314.3*Tcr);
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}
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double leekesler::Tcrit() {return Tcr;}
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double leekesler::Pcrit() {return Pcr;}
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double leekesler::Vcrit() {return 0.2901*8314.3*Tcr/(Pcr*Mw);}
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double leekesler::Tmin() {return -100.0;}
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double leekesler::Tmax() {return 10000.0;}
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char * leekesler::name() {return "Lee-Kesler";}
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char * leekesler::formula() {return "---";}
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double leekesler::MolWt() {return Mw;}
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}
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