initial commit / add all books

1 files changed, 99 insertions, 0 deletions

diff --git a/1309/CH9/EX9.4/ch9_4.sce b/1309/CH9/EX9.4/ch9_4.sce
new file mode 100755
index 000000000..756c2e166
--- /dev/null
+++ b/1309/CH9/EX9.4/ch9_4.sce
@@ -0,0 +1,99 @@
+clc;
+clear;
+printf("\t\t\tChapter9_example4\n\n\n");
+// Determination of (a) no. of exchangers required, (b)  the overall  coefficient of (all) the exchanger(s), and (c) the pressure drop for each stream. 
+// assuming counterflow arrangement
+// properties of air at 323 K. from appendix table D1
+rou_1= 1.088; // density in kg/m^3 
+cp_1= 1007; // specific heat in J/(kg*K) 
+v_1= 18.2e-6; // viscosity in m^2/s  
+Pr_1 =0.703; // Prandtl Number 
+kf_1= 0.02814; // thermal conductivity in W/(m.K)
+a_1 = 0.26e-4; // diffusivity in m^2/s 
+m_1=100; // mass flow rate in kg/hr
+// temperatures in K
+t1_air=20+273; 
+t2_air=80+273;
+// properties of carbon dioxide at [600 + (20 + 273)]/2 = 480 = 500 K. from appendix table D2
+rou_2= 1.0732; // density in kg/m^3 
+cp_2= 1013; // specific heat in J/(kg*K) 
+v_2= 21.67e-6; // viscosity in m^2/s  
+Pr_2 =0.702; // Prandtl Number 
+kf_2= 0.03352; // thermal conductivity in W/(m.K)
+a_2 = 0.3084e-4; // diffusivity in m^2/s 
+m_2=90; // mass flow rate in kg/hr
+// temperatures in K
+T1_CO2=600; 
+// specifications of seamless copper tubing from appendix table F2
+ID_a=.098;
+ID_p=.07384;
+OD_p=.07938;
+// Flow Areas
+A_p=%pi*ID_p^2/4;
+A_a=%pi*((ID_a)^2-(OD_p)^2)/4;
+printf("\nThe area of annulus is %.2e sq.m",A_a);
+printf("\nThe area of inner pipe is %.2e sq.m",A_p);
+if A_a>A_p then
+    printf("\nAir flows through annulus");
+    else printf("\nair flows through inner pipe");
+end
+// Heat Balance 
+q_air=(m_1/3600)*(cp_1)*(t2_air-t1_air);
+printf("\nThe heat transferred is %.2e W",q_air);
+T2_CO2=T1_CO2-(q_air/(m_2*cp_2/3600));
+printf("\nThe low temperature of carbon dioxide is %d K",T2_CO2);
+// Log-Mean Temperature Difference
+LMTD_counter=((T1_CO2-t2_air)-(T2_CO2-t1_air))/(log((T1_CO2-t2_air)/(T2_CO2-t1_air)));
+printf("\nThe LMTD for counter flow configuration is %d degree C",LMTD_counter);
+// Annulus Equivalent Diameters
+D_h=ID_a-OD_p;
+D_e=(ID_a^2-OD_p^2)/(OD_p);
+printf("\nThe Annulus Equivalent Diameter for friction is %.5f m",D_h);
+printf("\nThe Annulus Equivalent Diameter for heat transfer is %.4f m",D_e);
+// Reynolds Numbers 
+Re_1=(m_1/3600)*(ID_p)/(v_1*rou_1*A_p);
+printf("\nThe Reynolds Number for air is %.2e",Re_1);
+Re_2=(m_2/3600)*(D_e)/(v_2*rou_2*A_a);
+printf("\nThe Reynolds Number for carbon dioxide is %.2e",Re_2);
+// Nusselt numbers
+Nu_1=0.023*(Re_1)^(4/5)*(Pr_1)^0.3;
+Nu_2=0.023*(Re_2)^(4/5)*(Pr_2)^0.4;
+printf("\nThe Nusselt number for air is %.1f",Nu_1);
+printf("\nThe Nusselt number for carbon dioxide is %.1f",Nu_2);
+// Convection Coefficients 
+h_1i=Nu_1*kf_1/ID_p;
+h_1o=h_1i*ID_p/OD_p;
+h_2=Nu_2*kf_2/D_e;
+printf("\nThe convective coefficient for air based on inner diameter is %.1f W/(sq.m.K)",h_1i);
+printf("\nThe convective coefficient for air based on outer diameter is %.1f W/(sq.m.K)",h_1o);
+printf("\nThe convective coefficient for carbon dioxide is %.1f W/(sq.m.K)",h_2);
+// Fouling Factors in (m^2.K)/W
+Rd_air=.0004;
+Rd_CO2=0.002;
+// exchanger coefficients
+Uo=1/((1/h_1o)+(1/h_2));
+Uo=1/((1/Uo)+Rd_air+Rd_CO2);
+printf("\nThe overall exchanger coefficient is %.1f W/(sq.m.K)",Uo);
+// area required
+A=q_air/(Uo*LMTD_counter);
+printf("\nThe area required is %.2f sq.m",A);
+// surface area of one exchanger is A=%pi*OD*L, so
+L=(A/(%pi*OD_p)); // length of each exchanger
+L_available=2; // available exchanger length
+N=L_available/L; // no. of exchangers
+printf("\nThe number of exchangers is %d",N);
+//friction factors
+fp=0.0245; //friction factor for air fom figure 6.14 corresponding to Reynolds Number calculated above
+fa=0.033; //friction factor for carbon dioxide fom figure 6.14 corresponding to Reynolds Number calculated above
+// Velocities
+V_air=(m_1/3600)/(rou_1*A_p);
+V_CO2=(m_2/3600)/(rou_2*A_a);
+printf("\nThe velocity of air is %.2f m/s",V_air);
+printf("\nThe velocity of carbon dioxide is %.2f m/s",V_CO2);
+// pressure drops
+dP_p=(fp*L_available*rou_1*V_air^2)/(ID_p*2);
+dP_a=((rou_2*V_CO2^2)/2)*((fa*L_available/D_h)+1);
+printf("\nThe pressure drop for tube side is %.2f Pa",dP_p);
+printf("\nThe pressure drop for shell side is %d Pa",dP_a);
+printf("\n\t\t\tSummary of Requested Information\n");
+printf("(a) Exchanger required: %d\n(b)Overall exchanger coefficient = %.1f W/(sq.m.K)\n(c)Air pressure drop = %.2f Pa\nDiesel exhaust pressure drop = %d Pa",N,Uo,dP_p,dP_a);