diff options
Diffstat (limited to '1328/CH2')
| -rw-r--r-- | 1328/CH2/EX2.1/2_1.sce | 11 | ||||
| -rw-r--r-- | 1328/CH2/EX2.2/2_2.sce | 31 | ||||
| -rw-r--r-- | 1328/CH2/EX2.3/2_3.sce | 16 | ||||
| -rw-r--r-- | 1328/CH2/EX2.4/2_4.sce | 10 | ||||
| -rw-r--r-- | 1328/CH2/EX2.5/2_5.sce | 18 |
5 files changed, 86 insertions, 0 deletions
diff --git a/1328/CH2/EX2.1/2_1.sce b/1328/CH2/EX2.1/2_1.sce new file mode 100644 index 000000000..c134c4e1d --- /dev/null +++ b/1328/CH2/EX2.1/2_1.sce @@ -0,0 +1,11 @@ +printf("\t Example 2.1 \n");
+printf("\t approximate values are mentioned in the book \n");
+Tavg=900; // average temperature of the wall,F
+k=0.15; // Thermal conductivity at 932 F,Btu/(hr)(ft^2)(F/ft)
+T1=1500; // hot side temperature,F
+T2=300; // cold side temperature,F
+A=192; // surface area,ft^2
+L=0.5; // thickness,ft
+Q=(k)*(A)*(T1-T2)/L; // formula for heat,Btu/hr
+printf("\t heat is : %.2e Btu/hr \n",Q);
+//end
diff --git a/1328/CH2/EX2.2/2_2.sce b/1328/CH2/EX2.2/2_2.sce new file mode 100644 index 000000000..ca133d6b9 --- /dev/null +++ b/1328/CH2/EX2.2/2_2.sce @@ -0,0 +1,31 @@ +printf("\t Example 2.2 \n");
+printf("\t approximate values are mentioned in the book \n");
+La=8/12; // Thickness of firebrick wall,ft
+Lb=4/12; // Thickness of insulating brick wall,ft
+Lc=6/12; // Thickness of building brick wall,ft
+Ka=0.68; // themal conductivity of firebrick,Btu/(hr)*(ft^2)*(F/ft)
+Kb=0.15; // themal conductivity of insulating brick,Btu/(hr)*(ft^2)*(F/ft)
+Kc=0.40; // themal conductivity of building brick,Btu/(hr)*(ft^2)*(F/ft)
+A=1; // surface area,ft^2
+Ta=1600; // temperature of inner wall,F
+Tb=125; // temperature of outer wall.F
+Ra=La/(Ka)*(A); // formula for resistance,(hr)*(F)/Btu
+printf("\t resistance offered by firebrick : %.2f (hr)*(F)/Btu \n",Ra);
+Rb=Lb/(Kb)*(A); // formula for resistance,(hr)*(F)/Btu
+printf("\t resistance offered by insulating brick : %.2f (hr)*(F)/Btu \n",Rb);
+Rc=Lc/(Kc)*(A); // formula for resistance,(hr)*(F)/Btu
+printf("\t resistance offered by buildingbrick : %.2f (hr)*(F)/Btu \n",Rc);
+R=Ra+Rb+Rc; // total resistance offered by three walls,(hr)*(F)/Btu
+printf("\t total resistance offered by three walls : %.2f (hr)*(F)/Btu \n",R);
+Q=(1600-125)/4.45; // using formula for heat loss/ft^2,Btu/hr
+printf("\t heat loss/ft^2 : %.0f Btu/hr \n",Q);
+// T1,T2 are temperatures at interface of firebrick and insulating brick, and insulating brick and building brick respectively,F
+delta=(Q)*(Ra); // formula for temperature difference,F
+printf("\t delta is : %.0f F \n",delta);
+T1=Ta-((Q)*(Ra)); // temperature at interface of firebrick and insulating brick,F
+printf("\t temperature at interface of firebrick and insulating brick :%.0f F \n",T1);
+deltb=Q*(Rb);
+printf("\t deltb is : %.0f F \n",deltb);
+T2=T1-((Q)*(Rb)); //temperature at interface of insulating brick and building brick,F
+printf("\t temperature at interface of insulating brick and building brick :%.0f F \n",T2);
+//end
diff --git a/1328/CH2/EX2.3/2_3.sce b/1328/CH2/EX2.3/2_3.sce new file mode 100644 index 000000000..c05db8979 --- /dev/null +++ b/1328/CH2/EX2.3/2_3.sce @@ -0,0 +1,16 @@ +printf("\t example 2.3 \n");
+printf("\t approximate values are mentioned in the book \n");
+Lair=0.25/12; // thickness of air film,ft
+Kair=0.0265; // thermal conductivity of air at 572F,Btu/(hr)*(ft^2)(F/ft)
+A=1; // surface area,ft^2
+Rair=Lair/(Kair*(A)); // resistance offered by air film, (hr)(F)/Btu
+printf("\t resistance offered by air film %.2f (hr)(F)/Btu \n",Rair);
+R=4.45; // resistance from previous example 2.2,(hr)(F)/Btu
+Rt=(R)+Rair; // total resistance,(hr)(F)/Btu
+printf("\t total resistance %.2f (hr)(F)/Btu \n",Rt);
+Ta=1600; // temperature of inner wall,F
+Tb=125; // temperature of outer wall,F
+Q=(1600-125)/Rt; // heat loss, Btu/hr
+printf("\t heat loss %.2f Btu/hr \n",Q);
+printf("\t It is seen that in a wall 18 in. thick a stagnant air gap only .25 in. thick reduces the heat loss by 15 percent \n");
+//end
diff --git a/1328/CH2/EX2.4/2_4.sce b/1328/CH2/EX2.4/2_4.sce new file mode 100644 index 000000000..b0f4ef99e --- /dev/null +++ b/1328/CH2/EX2.4/2_4.sce @@ -0,0 +1,10 @@ +printf("\t example 2.4 \n");
+printf("\t approximate values are mentioned in the book \n");
+k=0.63; // thermal conductivity of pipe, Btu/(hr)*(ft^2)*(F/ft)
+Do=6; // in
+Di=5; // in
+Ti=200; // inner side temperature,F
+To=175; // outer side temperature,F
+q=(2*(3.14)*(k)*(Ti-To))/(2.3*log10(Do/Di)); // formula for heat flow,Btu/(hr)*(ft)
+printf("\t heat flow is : %.0f Btu/(hr)*(ft) \n",q); // caculation mistake in book
+// end
diff --git a/1328/CH2/EX2.5/2_5.sce b/1328/CH2/EX2.5/2_5.sce new file mode 100644 index 000000000..74052be15 --- /dev/null +++ b/1328/CH2/EX2.5/2_5.sce @@ -0,0 +1,18 @@ +printf("\t example 2.5 \n");
+printf("\t approximate values are mentioned in the book \n");
+t1=150; // assume temperature of outer surface of rockwool,F
+ta=70; // temperature of surrounding air,F
+ha=2.23; // surface coefficient,Btu/(hr)*(ft^2)*(F)
+q=(3.14)*(300-70)/(((2.3/(2*0.033))*log10(3.375/2.375))+(1/((2.23)*(3.375/12)))); // using formula for heat loss,Btu/(hr)*(lin ft), calculation mistake
+printf("\t heat loss for linear foot is : %.1f Btu/(hr)*(lin ft) \n",q);
+printf("\t Check between ts and t1, since delt/R = deltc/Rc \n");
+t1=300-(((104.8)*((2.3)*(log10(3.375/2.375))))/((2)*(3.14)*(.033))); // using eq 2.31,F
+printf("\t t1 is : %.1f F \n",t1);
+t1=125; // assume temperature of outer surface of rockwool,F
+ha=2.10; // surface coefficient,Btu/(hr)*(ft^2)*(F)
+q=((3.14)*(300-70))/(((2.3/(2*0.033))*log10(3.375/2.375))+(1/((2.10)*(3.375/12)))); // using formula for heat loss,Btu/(hr)*(lin ft)
+printf("\t heat loss for linear foot is : %.1f Btu/(hr)*(lin ft) \n",q);
+printf("\t Check between ts and t1, since delt/R = deltc/Rc \n");
+t1=300-(((103)*((2.3)*(log10(3.375/2.375))))/((2)*(3.14)*(.033))); // using eq 2.31,F
+printf("\t t1 is : %.1f F \n",t1);
+// end
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