initial commit / add all books

3 files changed, 54 insertions, 0 deletions

diff --git a/2510/CH21/EX21.1/Ex21_1.sce b/2510/CH21/EX21.1/Ex21_1.sce
new file mode 100755
index 000000000..d8d30f789
--- /dev/null
+++ b/2510/CH21/EX21.1/Ex21_1.sce
@@ -0,0 +1,22 @@
+//Variable declaration:
+m = 1                           //Mass flowrate (lb)
+cP = 1                          //Heat capacity (Btu/lb. F)
+//From figure 21.3:
+T1 = 300                        //Temperature of hot fluid leaving exchanger ( F)
+T2 = 540                        //Temperature of hot fluid entering exchanger ( F)
+T3 = 60                         //Temperature of cold fluid leaving exchanger ( F)
+T4 = 300                        //Temperature of cold fluid entering exchanger ( F)
+
+//Calculation:
+DSh = m*cP*log((T1+460)/(T2+460))      //Entropy for hot fluid (Btu/ F)
+DSc = m*cP*log((T4+460)/(T3+460))      //Entropy for cold fluid (Btu/ F)
+DSa = DSh+DSc                   //Entropy for one exchanger (Btu/ F)
+DSt = DSa*2                     //Total entropy change (Btu/ F)
+
+//Result:
+printf("The entropy chage is : %.4f Btu/ F .",DSt)
+if (DSt>0) then
+    printf("There is a positive entropy change.")
+else 
+    printf("There is a negative entropy change.")
+end    
diff --git a/2510/CH21/EX21.2/Ex21_2.sce b/2510/CH21/EX21.2/Ex21_2.sce
new file mode 100755
index 000000000..f5b06ae38
--- /dev/null
+++ b/2510/CH21/EX21.2/Ex21_2.sce
@@ -0,0 +1,16 @@
+//Variable declaration:
+//From example 21.1:
+DSh = -0.2744                   //Entropy for hot fluid (Btu/ F)
+DSc = 0.3795                    //Entropy for cold fluid (Btu/ F)
+m = 1                           //Mass flowrate (lb)
+cP = 1                          //Heat capacity (Btu/lb. F)
+//From figure 21.4:
+DT = 0                          //Temperature difference driving force ( F)
+DS_D = 0                        //Entropy for D exchanger (Btu/ F)
+
+//Calculation:
+DS_C = DSh+DSc                  //Entropy for C exchanger (Btu/ F)
+DSt = DS_C+DS_D                 //Total entropy change of exchangers (Btu/ F)
+
+//Result:
+printf("The total entropy change is : %f Btu/ F .",DSt)
diff --git a/2510/CH21/EX21.3/Ex21_3.sce b/2510/CH21/EX21.3/Ex21_3.sce
new file mode 100755
index 000000000..a340e8add
--- /dev/null
+++ b/2510/CH21/EX21.3/Ex21_3.sce
@@ -0,0 +1,16 @@
+//Variable declaration:
+//From figure 21.5:
+m = 2                           //Mass flowrate (lb)
+cP = 1                          //Heat capacity (Btu/lb. F)
+DS1 = -0.2744                   //Entropy for hot fluid for E exchanger (Btu/ F)
+T1 = 180                        //Temperature cold fluid entering the E exchabger ( F)
+T2 = 60                         //Temperature cold fluid leaving the E exchabger ( F)
+
+//Calculation:
+DS2 = m*cP*log((T1+460)/(T2+460))   //Entropy for cold fluid for E exchanger (Btu/ F)
+DS_E = DS1+DS2                  //Entropy for E exchanger (Btu/ F)
+DS_F = DS_E                     //Entropy for F exchanger (Btu/ F)
+DSt = DS_F+DS_E                 //Entropy change in exchangers E and F (Btu/ F)
+
+//Result:
+printf("The entropy change in exchangers E and F is : %.4f Btu/ F",DSt)