diff options
Diffstat (limited to '839/CH15')
-rwxr-xr-x | 839/CH15/EX15.4/Example_15_4.sce | 108 |
1 files changed, 54 insertions, 54 deletions
diff --git a/839/CH15/EX15.4/Example_15_4.sce b/839/CH15/EX15.4/Example_15_4.sce index 2a1724600..857829a79 100755 --- a/839/CH15/EX15.4/Example_15_4.sce +++ b/839/CH15/EX15.4/Example_15_4.sce @@ -1,54 +1,54 @@ -//clear//
-clear;
-clc;
-
-//Example 15.4
-//Given
-N = 28;
-xF = 0.5/12; // [ft]
-yF = 0.035/12; //[ft]
-km = 26; // [Btu/ft-h-F]
-AT = 2.830; //[ft^2/ft]
-Ab = 0.416; //[ft^2/ft]
-hi = 1500; //[Btu/ft^2-h-F]
-G = 5000; //[lb/h-ft^2]
-Tavg = 130; //[F]
-Tw = 250; //[F]
-mu = 0.046; //[lb/ft-h], from Appendix 8
-Cp = 0.25; //[Btu/lb-F], from Appendix 15
-k = 0.0162; //[Btu/ft-h-F], from Appendix 12
-ID_shell = 3.068/12; //[ft], from Appendix 5
-OD_pipe = 1.9/12; //[ft], from Appendix 5
-//cross sectional area of shell space
-Ac = %pi/4*(ID_shell^2-OD_pipe^2)-N*xF*yF //[ft^2]
-//The perimeter of air space
-Ap = %pi*ID_shell+AT; //[ft]
-//hydraulic radius
-rh = Ac/Ap; //[ft]
-//equivalent diameter
-De = 4*rh; //[ft]
-//Reynolds Number
-Nre = De*h/mu
-//In computing mu_w the resistance of the wall and the steam film
-//are considered negligible, so
-mu_w = 0.0528; //[lb/ft-h]
-Npr = mu*Cp/k
-//Using Fig. 15.17, the heat transfer factor is
-jh = 0.0031;
-ho = jh*Cp*G*(mu/mu_w)^0.14/Npr^(2/3); //[Btu/ft^2-h-F]
-
-//For rectangular fins, disreagrding the contribution of the ends of the fins to
-//the perimeter, Lp = 2L and S = Lyf, where yf is the fin thickness and L is the
-//length of the fin. Then, from Eq.(15.11)
-aFxF = xF*sqrt(2*ho/(km*yF));
-//From Fig. 15.16
-netaF = 0.93;
-Dt = 1.610/12; //[ft], from Appendix 5
-DLbar = (OD_pipe-Dt)/log(OD_pipe/Dt); //[ft]
-Ai = %pi*Dt*1.0; //[ft^2]
-AF = AT-Ab; //[ft^2/ft]
-xw = (OD_pipe-Dt)/2; //[ft]
-
-//Using Eq.(15.10), the overall coefficient
-Ut = 1/(Ai/(ho*(netaF*AF+Ab))+(xw*Dt/(km*DLbar))+1/hi);//[Btu/ft^2-h-F]
-disp('Btu/ft^2-h-F',Ut,'The overall heat transfer coefficent is')
+//clear// +clear; +clc; + +//Example 15.4 +//Given +N = 28; +xF = 0.5/12; // [ft] +yF = 0.035/12; //[ft] +km = 26; // [Btu/ft-h-F] +AT = 2.830; //[ft^2/ft] +Ab = 0.416; //[ft^2/ft] +hi = 1500; //[Btu/ft^2-h-F] +G = 5000; //[lb/h-ft^2] +Tavg = 130; //[F] +Tw = 250; //[F] +mu = 0.046; //[lb/ft-h], from Appendix 8 +Cp = 0.25; //[Btu/lb-F], from Appendix 15 +k = 0.0162; //[Btu/ft-h-F], from Appendix 12 +ID_shell = 3.068/12; //[ft], from Appendix 5 +OD_pipe = 1.9/12; //[ft], from Appendix 5 +//cross sectional area of shell space +Ac = %pi/4*(ID_shell^2-OD_pipe^2)-N*xF*yF //[ft^2] +//The perimeter of air space +Ap = %pi*ID_shell+AT; //[ft] +//hydraulic radius +rh = Ac/Ap; //[ft] +//equivalent diameter +De = 4*rh; //[ft] +//Reynolds Number +Nre = De*G/mu +//In computing mu_w the resistance of the wall and the steam film +//are considered negligible, so +mu_w = 0.0528; //[lb/ft-h] +Npr = mu*Cp/k +//Using Fig. 15.17, the heat transfer factor is +jh = 0.0031; +ho = jh*Cp*G*(mu/mu_w)^0.14/Npr^(2/3); //[Btu/ft^2-h-F] + +//For rectangular fins, disregarding the contribution of the ends of the fins to +//the perimeter, Lp = 2L and S = Lyf, where yf is the fin thickness and L is the +//length of the fin. Then, from Eq.(15.11) +aFxF = xF*sqrt(2*ho/(km*yF)); +//From Fig. 15.16 +netaF = 0.93; +Dt = 1.610/12; //[ft], from Appendix 5 +DLbar = (OD_pipe-Dt)/log(OD_pipe/Dt); //[ft] +Ai = %pi*Dt*1.0; //[ft^2] +AF = AT-Ab; //[ft^2/ft] +xw = (OD_pipe-Dt)/2; //[ft] + +//Using Eq.(15.10), the overall coefficient +Ut = 1/(Ai/(ho*(netaF*AF+Ab))+(xw*Dt/(km*DLbar))+1/hi);//[Btu/ft^2-h-F] +disp('Btu/ft^2-h-F',Ut,'The overall heat transfer coefficient is')
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