6 files changed, 282 insertions, 0 deletions
diff --git a/530/CH6/EX6.1/example_6_1.sce b/530/CH6/EX6.1/example_6_1.sce
new file mode 100755
index 000000000..2f50868ca
--- /dev/null
+++ b/530/CH6/EX6.1/example_6_1.sce
@@ -0,0 +1,54 @@
+clear;
+clc;
+
+// A Textbook on HEAT TRANSFER by S P SUKHATME
+// Chapter 6
+// Heat Transfer by Natural Convection
+
+
+// Example 6.1
+// Page 258
+printf("Example 6.1, Page 258 \n \n");
+
+H = 0.5 ; // [m]
+T_h = 100; // [degree C]
+T_l = 40; // [degree C]
+
+v = 20.02*10^-6 ; // [m/s]
+Pr = 0.694; 
+k = 0.0297; // [W/m K]
+
+T = (T_h+T_l)/2 + 273 ; // [K]
+printf("Mean film temperature = %f K \n",T);
+B = 1/T;
+
+Gr = 9.81*B*((T_h-T_l)*H^3)/(v^2);
+Ra = Gr*Pr;
+
+// (a)
+// Exact analysis - Equation 6.2.17
+disp("(a)");
+printf("Exact analysis\n");
+Nu_a = 0.64*(Gr^(1/4))*(Pr^0.5)*((0.861+Pr)^(-1/4));
+printf("Nu_L = %f \n",Nu_a);
+
+// (b)
+// Integral method - Equation 6.2.29
+disp("(b)");
+printf("Integral method \n");
+Nu_b = 0.68*(Gr^(1/4))*(Pr^0.5)*((0.952+Pr)^(-1/4));
+printf("Nu_L = %f \n",Nu_b);
+
+// (c)
+// McAdams correlation - Equation 6.2.30
+disp("(c)");
+printf("McAdams correlation \n");
+Nu_c = 0.59*(Ra)^(1/4);
+printf("Nu_L = %f \n",Nu_c);
+
+// (d)
+// Churchill and Chu correlation - Equation 6.2.31
+disp("(d)")
+printf("Churchill and Chu correlation\n");
+Nu_d = 0.68 + 0.670*(Ra^(1/4))/[1+(0.492/Pr)^(9/16)]^(4/9);
+printf("Nu_L = %f \n",Nu_d);
+\ No newline at end of file
diff --git a/530/CH6/EX6.2/example_6_2.sce b/530/CH6/EX6.2/example_6_2.sce
new file mode 100755
index 000000000..b3c62df32
--- /dev/null
+++ b/530/CH6/EX6.2/example_6_2.sce
@@ -0,0 +1,41 @@
+clear;
+clc;
+
+// A Textbook on HEAT TRANSFER by S P SUKHATME
+// Chapter 6
+// Heat Transfer by Natural Convection
+
+
+// Example 6.2
+// Page 259
+printf("Example 6.2, Page 259 \n \n");
+
+Tm = 150 ; // [degree C]
+// From table A.2
+v = 28.95*10^-6 ; // [m^2/s]
+Pr = 0.683;
+k = 0.0357 ; // [W/m K]
+
+B = 1/(273+Tm); // [K^-1]
+
+// from eqn 6.2.30
+printf("Equation 6.2.30 \n h = k/L*0.59*[9.81*B*(Tw-Tinf)*(L^3)*0.683/(v^2)]^(1/4)\n")
+// h = k/L*0.59*[9.81*B*(Tw-Tinf)*(L^3)*0.683/(v^2)]^(1/4);
+// simplifying we get
+// h = 1.38*[(Tw-Tinf)/L]^(1/4)
+printf("Reduces to h = 1.38*[(Tw-Tinf)/L]^(1/4) \n")
+
+
+// From eqn 6.2.33
+// h*L/k = 0.10*[9.81*B*(Tw-Tinf)*(L^3)*0.683/(v^2)]^(1/3);
+printf("Equation 6.2.33 \n h*L/k = 0.10*[9.81*B*(Tw-Tinf)*(L^3)*0.683/(v^2)]^(1/3) \n");
+// simplifying
+// h = 0.95*(Tw-Tinf)^1/3
+printf("Reduces to h = 0.95*(Tw-Tinf)^1/3 \n");
+
+printf("where h is expressed in W/m^2 K, (Tw-Tinf) in C and L in metres \n");
+
+
+
+
+
diff --git a/530/CH6/EX6.3/example_6_3.sce b/530/CH6/EX6.3/example_6_3.sce
new file mode 100755
index 000000000..fb624c2dd
--- /dev/null
+++ b/530/CH6/EX6.3/example_6_3.sce
@@ -0,0 +1,51 @@
+clear;
+clc;
+
+// A Textbook on HEAT TRANSFER by S P SUKHATME
+// Chapter 6
+// Heat Transfer by Natural Convection
+
+
+// Example 6.3
+// Page 260
+printf("Example 6.3, Page 260 \n \n");
+
+s = 0.2 ; // [m]
+d = 0.005 ; // [m]
+rho = 7900 ; // [kg/m^3]
+Cp = 460 ; // [J/kg K]
+
+T_air = 20 ; // [C]
+// For 430 C to 330 C
+T_avg = 380 ; // [C]
+Tm = (T_avg + T_air)/2 ; // [C]
+
+
+v = 34.85*10^-6 ; // [m^2/s]
+Pr = 0.680 ;
+k = 0.0393 ; // [W/m K]
+
+Re = 9.81*1/(273+Tm)*(T_avg-T_air)*(s^3)/(v^2)*Pr;
+
+// From eqn 6.2.31
+Nu = 0.68 + 0.670*(Re^(1/4))/[1+(0.492/Pr)^(4/9)]^(4/9);
+
+h = Nu*k/s; // [W/m^2 K]
+t1 = rho*s*s*d*Cp/((s^2)*2*h)*log((430-T_air)/(330-T_air)); // [s]
+printf("Time required for the plate to cool from 430 C to 330 C is %f s\n",t1);
+
+// for 330 to 230
+h2 = 7.348 ; // [W/m^2 K]
+t2 = rho*s*s*d*Cp/((s^2)*2*h2)*log((330-T_air)/(230-T_air)); // [s]
+printf("Time required for the plate to cool from 330 C to 230 C is %f s\n",t2);
+
+// for 230 to 130
+h3 = 6.780; // [W/m^2 K]
+t3 = rho*s*s*d*Cp/((s^2)*2*h3)*log((230-T_air)/(130-T_air)); // [s]
+printf("Time required for the plate to cool from 230 C to 130 C is %f s\n",t3);
+
+// Total time
+
+time = t1+t2+t3;
+minute = time/60;
+printf("Hence, time required for the plate to cool from 430 C to 130 C \n = %f s\n = %f min",time,minute);
diff --git a/530/CH6/EX6.4/example_6_4.sce b/530/CH6/EX6.4/example_6_4.sce
new file mode 100755
index 000000000..6ecb437b0
--- /dev/null
+++ b/530/CH6/EX6.4/example_6_4.sce
@@ -0,0 +1,61 @@
+clear;
+clc;
+
+// A Textbook on HEAT TRANSFER by S P SUKHATME
+// Chapter 6
+// Heat Transfer by Natural Convection
+
+
+// Example 6.4
+// Page 264
+printf("Example 6.4, Page 264 \n \n");
+
+D = 0.006 ; // [m]
+e = 0.1 ;
+Ti = 800 ; // [C]
+Ta = 1000 ; // [C]
+// Rate at which heat gained = net radiant heat, gives h*(Ta-800) = 1306.0 ; // [W/m^2]
+
+// Using trial and error method
+// Trial 1
+printf("Trial 1 \n");
+// Let Ta = 1000 degree C
+printf("Let Ta = 10000 C \n");
+
+Tm = (Ta+Ti)/2;
+// From table A.2
+v = 155.1*10^-6 ; // [m^2/s]
+k = 0.0763 ; // [W/m K]
+Pr = 0.717 ;
+
+Gr = 9.81*1/1173*(200*D^3)/(v^2);
+Ra = Gr*Pr ;
+
+// From eqn 6.3.2
+Nu = 0.36 + 0.518*(Ra^(1/4))/[1+(0.559/Pr)^(9/16)]^(4/9);
+h = Nu*k/D;
+x = h*(Ta-Ti); // [W/m^2]
+printf("Value of h(Ta-800) = %f W/m^2, which is much larger than the required value of 1306 W/m^2 \n",x);
+
+// Trial 2
+printf("\nTrial 2 \n");
+// Let Ta = 900
+printf("Let Ta = 900 C \n");
+Ra2 = 6.42 ;
+Nu2 = 0.9841 ;
+h2 = 12.15 ;
+x2 = h2*(900-800);
+printf("Value of h(Ta-800) = %f W/m^2, which is a little less than the required value of 1306 W/m^2 \n",x2);
+
+// Trial 3
+printf("\nTrial 3 \n");
+// Let Ta = 910 
+printf("Let Ta = 910 C \n");
+Ra3 = 6.93 ;
+Nu3 = 0.9963 ;
+h3 = 12.33 ;
+x3 = h3*(910-800);
+printf("Value of h(Ta-800) = %f W/m^2 \nThis value is little more than the required value of 1306 W/m^2 \n",x3);
+// Interpolation
+T = 900 + (910-900)*(1306-x2)/(x3-x2);
+printf("\nThe correct value of Ta obtained by interpolation is %f C",T);
diff --git a/530/CH6/EX6.5/example_6_5.sce b/530/CH6/EX6.5/example_6_5.sce
new file mode 100755
index 000000000..0c4952e64
--- /dev/null
+++ b/530/CH6/EX6.5/example_6_5.sce
@@ -0,0 +1,40 @@
+clear;
+clc;
+
+// A Textbook on HEAT TRANSFER by S P SUKHATME
+// Chapter 6
+// Heat Transfer by Natural Convection
+
+
+// Example 6.5
+// Page 269
+printf("Example 6.5, Page 269 \n \n");
+
+T_p = 75 ; // Temperature of absorber plate , degree C
+T_c = 55 ; // Temperature of glass cover , degree C
+L = 0.025 ; // [m]
+
+H = 2 ; // [m]
+Y = 70 ; // degree
+
+a = 19/180*%pi ; // [Radians]
+
+r = H/L ;
+
+T_avg = (T_p+T_c)/2+273 ; // [K]
+// Properties at 65 degree C
+k = 0.0294 ; // [W/m K]
+v = 19.50*10^-6 ; // [m^2/s]
+Pr = 0.695 ;
+
+Ra = 9.81*(1/T_avg)*(T_p-T_c)*(L^3)/(v^2)*Pr*cos(a);
+
+// From eqn 6.4.3
+Nu = 0.229*(Ra)^0.252;
+
+h = Nu*k/L ; // [W/m^2 K]
+
+Rate = h*2*1*(T_p-T_c); // [W]
+
+printf("Heat transfer rate = %f W",Rate);
+
diff --git a/530/CH6/EX6.6/example_6_6.sce b/530/CH6/EX6.6/example_6_6.sce
new file mode 100755
index 000000000..ff28ef8c4
--- /dev/null
+++ b/530/CH6/EX6.6/example_6_6.sce
@@ -0,0 +1,35 @@
+clear;
+clc;
+
+// A Textbook on HEAT TRANSFER by S P SUKHATME
+// Chapter 6
+// Heat Transfer by Natural Convection
+
+
+// Example 6.6
+// Page 270
+printf("Example 6.6, Page 270 \n \n");
+
+T_air = 30 ; // [C]
+D = 0.04 ; // [m]
+T_s = 70 ; // surface temperature, [C]
+V = 0.3 ; // [m/s]
+
+Tm = (T_air + T_s)/2 ; // [C]
+// Properties at Tm
+v = 17.95*10^-6 ; // [m^2/s]
+Pr = 0.698 ;
+k = 0.0283 ; // [W/m K]
+
+Gr = 9.81*1/323*(T_s-T_air)*(D^3)/v^2;
+Re = V*D/v ; 
+X = Gr/Re^2 ; 
+printf("Since Gr/Re^2 = %f is > 0.2, we have a combined convection situation. \n\n",X);
+
+// From Eqn 5.9.8
+Nu_forced = 0.3 + 0.62*(Re^0.5)*(Pr^(1/3))/[[1+(0.4/Pr)^(2/3)]^(1/4)]*[1+(Re/282000)^(5/8)]^(4/5);
+
+// Substituting in Eqn 6.5.1
+Nu = Nu_forced*[1+6.275*(X)^(7/4)]^(1/7);
+h = Nu*(k/D);
+printf("The Average heat transfer coefficient = %f W/m^2 K",h);
+\ No newline at end of file