1 files changed, 42 insertions, 0 deletions
diff --git a/1752/CH4/EX4.3/exa_4_3.sce b/1752/CH4/EX4.3/exa_4_3.sce
new file mode 100755
index 000000000..705f00c2e
--- /dev/null
+++ b/1752/CH4/EX4.3/exa_4_3.sce
@@ -0,0 +1,42 @@
+//Exa 4.3
+clc;
+clear;
+close;
+//given data
+k=40;// in W/mK
+rho=8200;// in kg/m^3
+C=400;// in J/kgK
+D=6*10^-3;// in m
+R=D/2;
+t_i=30;// in degree C
+t_infinite1=400;// for 10 sec in degree C
+t_infinite2=20;// for 10 sec in degree C
+h=50;// in W/m^2K
+
+// Part(a)
+//l_s= V/A = R/3
+l_s= R/3;// in m
+//toh= rho*V*C/(h*A) = rho*C*l_s/h
+toh= rho*C*l_s/h;// in sec
+disp(toh,"Time constance in sec")
+
+// Part (b)
+Bi= h*l_s/k;
+// since Bi < 0.1 , hence lumped heat capacity analysis is valid. Now , temperature attained by junction in 10 seconds when exposed to hot air at 400 degree C
+toh=10;// in sec
+// (t-t_infinite1)/(t_i-t_infinite1)= %e^(-h*A*toh/(rho*V*C)) = %e^(-h*toh/(rho*l_s*C))
+t= %e^(-h*toh/(rho*l_s*C))*(t_i-t_infinite1)+t_infinite1;// in degree C
+
+disp("The junction is taken out from hot air stream and placed in stream of still air 20 degree C. The initial temperature in this case will be "+string(t)+" .")
+t_i=t;
+toh=20;// in sec
+t= %e^(-h*toh/(rho*l_s*C))*(t_i-t_infinite2)+t_infinite2;// in degree C
+disp(t,"The temperature attained by junction in degree C");
+
+// Note: In the last, calculation to find the value of t is wrong so Answer in the book is wrong
+
+
+
+
+
+