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+clear;
+clc;
+
+// Illustration 2.9
+// Page: 123
+
+printf('Illustration 2.9 -  Page: 123\n\n');
+
+// solution
+//*****Data*****//
+// a-water    b-air
+dp1 = 10^-3; // [diameter of spherical drop of water, m]
+Tair = 323; // [K]
+P = 101.3; // [kPa]
+Twater = 293; // [K]
+R = 8.314; // [cubic m.Pa/mole.K]
+M_a = 18; // [gram/mole]
+M_b = 29; // [gram/mole]
+//*****//
+
+dp2 = (1/2)^(1/3)*dp1; // [m]
+dp = (dp1+dp2)/2; // [m]
+
+row_p = 995; // [density of water, kg/cubic m]
+row1b = 1.094; // [density of air, kg/cubic m]
+u = 1.95*10^-5; // [kg/m.s]
+row_pr = row_p-row1b; // [kg/cubic m]
+g = 9.8; // [accleration due to gravity, square m/s]
+// Combining equation 2.68 and 2.69
+Ga = 4*dp^3*row1b*row_pr*g/(3*u^2); // [Galileo Number]
+
+// Relationship between Re and Cd
+// Re/Cd = Re^3/Ga = 3*row^2*vt^3/(4*g*u*row_pr)
+
+// The following correlation is used to relate Re/Cd, to Ga
+// ln(Re/Cd)^(1/3) = -3.194 + 2.153*ln(Ga)^(1/3) - 0.238*(ln(Ga)^(1/3))^2 + 0.01068*(ln(Ga)^(1/3))^3
+// Therefore let A = (Re/Cd)
+A = exp(-3.194 + 2.153*log(Ga^(1/3)) - 0.238*(log(Ga^(1/3)))^2 + 0.01068*(log(Ga^(1/3)))^3);
+
+// Therefore 'vt' will be
+vt = A*(4*g*row_pr*u/(3*row1b^2))^(1/3); // [Terminal velocity of particle, m/s]
+printf("Terminal velocity of particle is %f m/s\n\n",vt); 
+
+P_w = 2.34; // [vapor pressure of water, kPa]
+y_w = P_w/P; // [mole fraction of water at the inner edge of the gas film]
+M_avg = 18*y_w+29*(1-y_w); // [gram/mole]
+
+row2b = P*M_avg/(R*Twater); // [kg/cubic.m]
+delta_row = row2b - row1b; // [kg/cubic.m]
+
+Tavg = (Tair+Twater)/2; // [K]
+// At Temperature equal to Tavg density and viscosity are
+row3 = 1.14; // [kg/cubic.m]
+u1 = 1.92*10^-5; // [kg/m.s]
+
+Grd = g*row3*delta_row*(dp^3)/(u1^2);
+
+// Diffusivity of water at Tavg and 1 atm is
+D_ab = 0.242*10^-4; // [square m/s]
+Sc = u1/(row3*D_ab); // [Schmidt Number]
+Re = dp*row3*vt/u1; // [Renoylds Number]
+
+// From equation 2.65 Re is greater than  0.4*Grd^0.5*Sc^(-1/6)
+// Therfore equation 2.64 can be used to calculate mass transfer coefficient
+
+Sh = 2+0.552*(Re^0.5)*Sc^(1/3); // [Sherwood Number]
+// From Table 2.1
+// Sh = kc*P_bm*dp/(P*D_ab), since P_bm is almost equal to P
+// Therefore 
+// Sh = kc*dp/D_ab;
+kc = Sh*D_ab/dp; // [m/s]
+
+ca2 = 0; // [dry air concentration]
+ca1 = P_w/(R*Twater); // [interface concentration, kmole/cubic.m]
+// Average rate of evaporation 
+wa = %pi*dp^2*M_a*kc*(ca1-ca2)*1000; // [g/s]
+
+// Amount of water evaporated
+m = row_p*%pi*dp1^3/12*1000; // [g]
+// Time necessary to reduce the volume by 50%
+t = m/wa; // [s]
+
+D = t*vt; // [distance of fall, m]
+printf("The distance of fall is %f m\n\n",D); 
+\ No newline at end of file