public static CalcResult ElementCal(string[] fluid, double[] composition, double dh, double l,
double Aa_fin, double Aa_tube, double A_r_cs, double Ar, double tai,
double tri, double pri, double hri, double mr, double g, double ma, double ha,
double eta_surface, double zh, double zdp, int hexType, double thickness, double conductivity, double Pwater)
{
var r = new Refrigerant.SATTTotalResult();
double href = 0;
double gg = 9.8;
double tsat;
int phase1 = 1;
int phase2 = 2;
tsat = Refrigerant.SATP(fluid, composition, pri, phase1).Temperature;
r = Refrigerant.SATTTotal(fluid, composition, tsat).SATTTotalResult;
double Vol_tubes = A_r_cs * l; //Tube volume, for charge calculation
double h_l = r.EnthalpyL;
double h_v = r.EnthalpyV;
double Tri_mod;
double alpha;
double M;
var res_element = new CalcResult();
// **********Superheated state**********
if (hri > h_v && fluid[0] != "Water")
{
if (hri < 1.02 * h_v)
{
Tri_mod = tri + 0.5; //"for Tri modification in the transition region"
}
else
{
Tri_mod = tri;
}
res_element = SPElement.ElementCalc(fluid, composition, dh, l, Aa_fin, Aa_tube, A_r_cs, Ar, tai, Tri_mod, pri, hri, mr, g, ma, ha, eta_surface, zh, zdp, hexType, thickness, conductivity, Pwater);
res_element.x_i = (hri - h_l) / (h_v - h_l);
res_element.x_o = (res_element.hro - h_l) / (h_v - h_l);
alpha = 1; //set void fraction to 1 to identify a superheated state
//{Equations are for charge calculation}
double T_avg = (tri + res_element.Tro) / 2; //Average temperature of the element
double P_avg = (pri + res_element.Pro) / 2; //Average pressure of the element
double rho = Refrigerant.TPFLSH(fluid, composition, T_avg + 273.15, P_avg).D *r.Wm; //density(ref$, T=T_avg, P=P_avg)
M = Vol_tubes * rho; //"Mass calculated"
}
// **********Twophase state**********"
if (hri <= h_v && hri >= h_l && fluid[0] != "Water")
{
res_element = TPElement.ElementCalc(fluid, composition, dh, l, Aa_fin, Aa_tube, A_r_cs, Ar, tai, tri, pri, hri, mr, g, ma, ha, eta_surface, zh, zdp, hexType, thickness, conductivity);
//x=x_o "outlet quality of the element"
double x_avg = (res_element.x_i + res_element.x_o) / 2; //Average quality of the element
if (x_avg < 0) //"If negative, set quality to inlet value"
{
x_avg = res_element.x_i;
}
double T_avg = (tri + res_element.Tro) / 2; //Average temperature of the element
//Call VOIDFRACTION_charge(ref$,x_avg, T_avg, G_r, Dh: alpha) "Average void fraction of the element"
alpha = 1;
//{Equations are for charge calculation}
double P_avg = (pri + res_element.Pro) / 2; //Average pressure of the element
double rho_l = Refrigerant.SATP(fluid, composition, P_avg, phase1).DensityL *r.Wm;
double rho_v = Refrigerant.SATP(fluid, composition, P_avg, phase1).DensityV *r.Wm;
//{Call VOIDFRACTION_pressure(ref$, x_avg, P_avg : alpha_p) "Baroczy void fraction model" }
M = Vol_tubes * (alpha * rho_v + (1 - alpha) * rho_l); //Mass calculated
}
//**********Subcooled state**********
if (hri < h_l || fluid[0] == "Water")
{
if (hri > 0.98 * h_l)
{
Tri_mod = tri - 0.5; //"for Tri modification in the transition region"
}
else
{
Tri_mod = tri;
}
if (fluid[0] == "Water")
{
Tri_mod = tri - 0.0001;
}
res_element = SPElement.ElementCalc(fluid, composition, dh, l, Aa_fin, Aa_tube, A_r_cs, Ar, tai, Tri_mod, pri, hri, mr, g, ma, ha, eta_surface, zh, zdp, hexType, thickness, conductivity, Pwater);
//Call SUBCOOLED(ref$, Dh, L, A_a, A_r, Tai, Tri_mod, Pri, hri, m_r, G_r, m_a, h_air, eta_surface: Tro, Pro, hro, Tao, Q, h_ref, R_1, R_1a, R_1r, DELTAP, Vel_r )
res_element.x_i = (hri - h_l) / (h_v - h_l);
res_element.x_o = (res_element.hro - h_l) / (h_v - h_l);
//x=x_o "outlet quality of the element"
//{x=-1 "set quality to -100 to identify a subcooled state"}
alpha = -1; //set void fraction to -100 to identify a subcooled state
//{Equations are for charge calculation}
double T_avg = (tri + res_element.Tro) / 2; //Average temperature of the element
double P_avg = (pri + res_element.Pro) / 2; //Average pressure of the element
double rho = Refrigerant.TPFLSH(fluid, composition, T_avg, P_avg).D *r.Wm; //density(ref$, T=T_avg, P=P_avg)
M = Vol_tubes * rho; //Mass calculated
}
return(res_element);
}
public static CalcResult ElementCalc(string[] fluid, double[] composition, double dh, double l, double Aa_fin, double Aa_tube, double A_r_cs, double Ar, double tai,
double tri, double pri, double hri, double mr, double g, double ma, double ha,
double eta_surface, double zh, double zdp, int hexType, double thickness, double conductivity)
{
double r_metal = thickness / conductivity / Ar;
double gg = 9.8;
//double temperature;
int phase1 = 1;
int phase2 = 2;
double q_initial = 0.01;
double q = q_initial;
double err = 0.01;
bool flag = false;
int iter = 1;
CalcResult res = new CalcResult();
//res.Tao[0] = new double();
var r = new Refrigerant.SATTTotalResult();
//temperature = Refrigerant.SATP(fluid, composition, pri, phase1).Temperature;
r = Refrigerant.SATTTotal(fluid, composition, tri + 273.15).SATTTotalResult; //temperature
res.x_i = (hri - r.EnthalpyL) / (r.EnthalpyV - r.EnthalpyL); //+ 140 for reference state, to be changed
RefHTCandDPResult htc_dp = new RefHTCandDPResult();
do
{
flag = false;
htc_dp = RefrigerantHTCandDP.HTCandDP(fluid, composition, dh, g, pri, res.x_i, l, q, zh, zdp);
res.href = htc_dp.Href;
res.DP = htc_dp.DPref;
double cp_a = 1.0; //keep it for now as a constant
cp_a = (hexType == 0 ? 1.027 : 1.02);
double C_a = ma * cp_a;
res.R_1a = 1 / ((eta_surface * Aa_fin + Aa_tube) * ha);
res.R_1r = 1 / (res.href * Ar);
res.R_1 = res.R_1a + res.R_1r + r_metal;
double UA = 1 / res.R_1;
double NTU = UA / (C_a * 1000);
double epsilon = 1 - Math.Exp(-NTU);
res.Q = epsilon * C_a * Math.Abs(tai - tri);
res.Tao = tai + Math.Pow(-1, (hexType + 1)) * res.Q / C_a;
res.hro = hri + Math.Pow(-1, hexType) * res.Q / mr;
//0:evap, 1:cond
res.x_o = (res.hro - r.EnthalpyL) / (r.EnthalpyV - r.EnthalpyL); //+ 139.17 for reference state, to be changed
//res.DP = 0;
res.Pro = pri - res.DP;
res.Tro = Refrigerant.PHFLSH(fluid, composition, res.Pro, (res.hro + (fluid[0] == "Water" ? 0 : 140)) * r.Wm).t; //
double rho_o = Refrigerant.TQFLSH(fluid, composition, res.Tro, res.x_o).D *r.Wm;
// .TPFLSH(fluid, composition, res.Tro, res.Pro).D * r.Wm;//wrong value
//double rho_o = Refrigerant.PHFLSH(fluid, composition, res.Pro, (res.hro + 140) * r.Wm).D * r.Wm;
//if (res.x_o > 1 || res.x_o < 0)
// rho_o = Refrigerant.PHFLSH(fluid, composition, res.Pro, res.hro).D;
////rho_o=density(ref$, P=Pri, T=Tro)
//else
// rho_o = 0;
// //rho_o=density(ref$, P=Pri, x=x_o)
res.Tro = res.Tro - 273.15;
res.Vel_r = g / rho_o;
if (Math.Abs(q - res.Q) / res.Q > err)
{
q = res.Q;
flag = true;
}
iter++;
} while (flag && iter < 100);
if (iter >= 100)
{
throw new Exception("iter for href > 100.");
}
return(res);
}
