clear; clc; // Illustration 2.8 // Page: 120 printf('Illustration 2.8 - Page: 120\n\n'); // solution //*****Data*****// // a-liquid benzene b-nitrogen T = 300; // [K] l = 3; // [length of vertical plate, m] b = 1.5; // [width of vertical plate, m] P = 101.3; // [kPa] v = 5; // [velocity across the width of plate, m/s] row_a = 0.88; // [gram/cubic cm] //*****// y_a1 = 0.139; // [mole fraction of benzene at inner edge] y_a2 = 0; // The film conditions, and average properties, are identical to those in Example 2.7, only the geometry is different // Therefore M_avg = 31.4; // [kg/kmole] row = 1.2; // [kg/cubic m] u = 161*10^-7; // [kg/m.s] D_ab = 0.0986; // [square cm/s] Sc = 1.3; // [Schmidt Number] Re = row*v*b/u; // [Renoylds Number] if(Re>4000) printf('The flow across the plate is turbulent\n\n'); else(Re<2000) printf('The flow across the plate is laminar\n\n'); end // Using equation 2.57 Sh_l = 0.036*Re^0.8*Sc^(1/3); // Nitrogen (component B) does not react with benzene (component A), neither dissolves in the liquid; therefore, NB = 0 and siA = 1. The F-form of the mass-transfer coefficient should be used F = Sh_l*1.26*D_ab*10^-4/(M_avg*b); // [kmole/square m.s] N_a = F*log((1-y_a2)/(1-y_a1)); // [kmole/square m.s] // The total mass rate of evaporation over the surface of the plate S = 1.5*3; // [square m] M_a = 78.1; // [gram/mole] wa = N_a*S*M_a*60*1000; // [gram/min] V = wa/row_a; // [volumetric flow rate, ml/min] printf("Liquid benzene should be supplied at the top of the plate at the rate %f ml/min so that evaporation will just prevent it from reaching the bottom of the plate.\n\n",V);