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authorpriyanka2015-06-24 15:03:17 +0530
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-rwxr-xr-x542/CH16/EX16.1/Example_16_1.sci30
-rwxr-xr-x542/CH16/EX16.2/Example_16_2.sci27
-rwxr-xr-x542/CH16/EX16.3/Example_16_3.sci60
-rwxr-xr-x542/CH16/EX16.4/Example_16_4.sci40
-rwxr-xr-x542/CH16/EX16.5/Example_16_5.sci77
-rwxr-xr-x542/CH16/EX16.6/Example_16_6.sci41
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diff --git a/542/CH16/EX16.1/Example_16_1.sci b/542/CH16/EX16.1/Example_16_1.sci
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+clear;
+clc;
+printf("\n Example 16.1");
+//For the first drying operation
+w1 = 0.25; //in kg/kg
+w = 0.10; //in kg/kg
+wc = 0.15; //in kg/kg
+we = 0.05; //in kg/kg
+f1 = w1-we; //in kg/kg
+fc = wc - we; //in kg/kg
+f = w - we; //in kg/kg
+
+//x = mA
+function[x]=TotalDryingTime(t)
+ x = (1/t)*[(f1-fc)/fc + log(fc/f)];
+ funcprot(0);
+endfunction
+printf("\n mA = %.3f kg/sec",TotalDryingTime(15));
+
+//For the second drying operation
+w12 = 0.30; //in kg/kg
+w2 = 0.08; //in kg/kg
+wc2 = 0.15; //in kg/kg
+we2 = 0.05; //in kg/kg
+f12 = w12 - we2; //in kg/kg
+fc2 = wc2 - we2; //in kg/kg
+f2 = w2 - we2; //in kg/kg
+
+t1=(1/TotalDryingTime(15))*[(0.25-0.10)/0.10 + log(0.10/0.03)];
+printf("\n The total drying time is then %.1f ksec or %.2f hr ",t1,t1*1000/3600);
diff --git a/542/CH16/EX16.2/Example_16_2.sci b/542/CH16/EX16.2/Example_16_2.sci
new file mode 100755
index 000000000..4f0f1ba41
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+++ b/542/CH16/EX16.2/Example_16_2.sci
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+clear;
+clc;
+printf("\n Example 16.2");
+E = [1 0.64 0.49 0.38 0.295 0.22 0.14];
+J = [0 0.1 0.2 0.3 0.5 0.6 0.7];
+plot(J,E,rect=[0,1,0,1]);
+xtitle("Plot for drying data","J = kt/L^2","E");
+
+//For the 10 mm strips
+mi = (0.28 - 0.07); //Initial free moisture content in kg/kg
+mf = (0.13-0.07); //Final free moisture content in kg/kg
+//at
+t = 25; //time is in ksecs
+E = (0.06/0.21);
+//at E = 0.286 ,J = 0.52 from the plot of given data and J = kt/L^2
+k = poly([0],'k');
+k1 = roots(0.52 - (k*t)/(10/2)^2);
+printf("\n k = %f",k1);
+
+//for the 60 mm planks
+m1i = (0.22 - 0.07); //Initial free moisture content in kg/kg
+m1f = (0.13 - 0.07); //Final free moisture content in kg/kg
+E = (m1f/m1i);
+//at E = 0.20 from yhe plot of the given data J = 0.63 and J = kt/L^2
+t1 = 0.63*(60/2)^(2)/k1;
+printf("\n t1 = %d ksecs or %.1f days",t1,(t1*1000/(3600*24)));
+
diff --git a/542/CH16/EX16.3/Example_16_3.sci b/542/CH16/EX16.3/Example_16_3.sci
new file mode 100755
index 000000000..cc88b6783
--- /dev/null
+++ b/542/CH16/EX16.3/Example_16_3.sci
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+clear;
+clc;
+printf("\n example 16.3");
+//(a) Air
+//G kg/s dry air enter with 0.006G kg/s water vapour and hence the heat content of this stream=
+//[(1.00G) + (0.006G × 2.01)](385 − 273) = 113.35G kW
+
+//(b) Wet solid
+//0.125 kg/s enter containing 0.40 kg water/kg wet solid, assuming the moisture is expressed on a wet basis.
+flowWater = (0.125*0.40); //in kg/sec
+flowDrySolid = (0.125-0.050); //in kg/sec
+//Hence heat content of this stream
+q = [(0.050*4.18)+(0.075*0.88)]*(295-273);
+printf("\n The heat content of this stream = %.2f kW",q);
+
+//Heat out
+//(a) Air
+//Heat in exit air = [(1.00 G) + (0.006 G × 2.01)](310 − 273) = 37.45G kW.
+fd = 0.075; //mass flow rate of dry solids in kg/sec
+w = 0.05*0.075/(1+0.05); //water in the dried solids leaving in kg/secs
+we = (0.050 - w); //The water evaporated into gas stream in kg/secs
+
+//Assuming evaporation takes place at 295 K,then:
+qout = 0.0464*[2.01*(310-295)+2449+4.18*(295-273)];
+printf("\n Heat in the water vapour = %.1f kW",qout);
+
+//the total heat in this stream = (119.30 + 37.45G) kW.
+//(b) Dried solids
+
+
+ //The dried solids contain 0.0036 kg/s water and hence heat conten t of this stream is:
+ q1 = [(0.075*0.88)+(0.0036*4.18)/(305-273)];
+ printf("\n The dried solids contain 0.0036 kg/s water and hence heat content of this stream is: %.2f kW",q1);
+
+
+//(c) Losses
+//These amount to 20 kJ/kg dry air or 20m kW.
+//Heat Balance
+G = poly([0],'G');
+G1 = roots(113.35*G + 6.05 - 119.30 - 37.45*G - 2.59 - 20*G);
+printf("\n G = %.2f kg/secs",G1);
+printf("\n Water in the outlet stream %.4f kg/secs",0.006*2.07+0.0464);
+printf("\n The humidity H = %.4f kg/kg dry air",0.0588/2.07);
+
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diff --git a/542/CH16/EX16.4/Example_16_4.sci b/542/CH16/EX16.4/Example_16_4.sci
new file mode 100755
index 000000000..0df32648e
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+clear;
+clc;
+printf("\n Example 16.4");
+//In 100 kg of feed
+
+ //mass of water =
+ mw = 100*30/100; //mass of water in kg
+ //mass of dry solids =
+ md = 100-30; //mass of dry solids
+
+//and:
+//For b kg water in the dried solids: 100b/(b + 70) = 15.5
+b = poly([0],'b');
+b1 = roots(100*b - 15.5*(b+70));
+printf("\n water in the product ,b = %.1f kg",b1);
+
+ //Initial water content
+ w1 = 30/70; //Intial moisture content in kg/kg dry solids
+ //Final moisture content
+ w2 = (12.8/70); //Final moisture content in kg/kg dry solids
+ //water to be removed
+ w3 = (30-12.8); //water to be removed in kg
+
+//Surface of drying
+S = (0.03*70); //Surface for drying in m^2
+rate = (0.0007*2.1); //Rate of drying in kg/sec
+
+//As the final moisture content is above the critical value, all the drying is at this constant rate and the time of drying is:
+t = 17.2/0.00147;
+printf("\n As the final moisture content is above the critical value, all the drying is at this constant rate and the time of drying is: %d ksecs or %.2f hr",t,t/3600);
+
+
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diff --git a/542/CH16/EX16.5/Example_16_5.sci b/542/CH16/EX16.5/Example_16_5.sci
new file mode 100755
index 000000000..a7e03099a
--- /dev/null
+++ b/542/CH16/EX16.5/Example_16_5.sci
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+clear;
+clc;
+printf("\n Example 16.5");
+//Inlet air temperature
+Tair = 400; //Inlet air temperature in kelvins
+H = 0.01; //Humidity is in kg/kg dry air
+//*therefore wet bulb temperature =
+Twetbulb = 312; //Inlet wet-bulb temperature
+NTU = 1.5; //Number of transfer units
+
+//Then for adiabatic drying the outlet air temperature,To is given by
+To = poly([0],'To');
+To1 = roots(exp(1.5)*(To-312)-(400-312));
+printf("\n For adiabatic drying the outlet air temperature = %.1f K",To1);
+
+//Solids outlet temperature will be taken to be maximum allowable,325K
+//From the steam tables in the Appendix, the latent heat of vaporisation of water at 312 K is2410 kJ/kg. Again from steam tables, the specific heat capacity of water vapour = 1.88 kJ/kg K and that of the solids will be taken as 2.18 kJ/kg K.
+
+//For a mass flow of solids of 0.35 kg/s and inlet and outlet moisture contents of 0.15 and 0.005 kg/kg dry solids respectively, the mass of water evaporated = 0.35(0.15 − 0.005) = 0.0508 kg/s.
+
+//For unit mass of solids ,the heat duty includes:
+ //Heat to the solids
+ qsolids = 2.18*(325-300); //heat to solids in kJ/kg
+ //Heat to raise the moisture to the dew point
+ qdew = (0.15*4.187*(312-300)); //in kJ/kg
+ //Heat of vaporisation
+ qvap = 2410*(0.15-0.005); //in kJ/kg
+ //Heat to raise remaining moisture to solids outlet temperature
+ qremaining = (0.05*4.187)*(325-312);
+ //Heat to raise evaporated moisture to the air outlet temp.
+ qevapo = (0.15-0.005)*1.88*(331.5-312);
+ qtotal = qsolids + qdew + qvap + qremaining + qevapo;
+ printf("\n Total heat = %.1f kJ/kg or %d kW",qtotal,qtotal*0.35);
+
+//The humid heat of entering air is 1.03 kJ/kg K
+ //G1 (1 +H1) = Q/Cp1(T1 − T2)
+ //where: G1 (kg/s) is the mass flowrate of inlet air,
+ //H1 (kg/kg) is the humidity of inlet air,
+ //Q (kW) is the heat duty,
+ //Cp1 (kJ/kg K) is the humid heat of inlet air
+ //and: T1 and T2 (K) are the inlet and outlet air temperatures respectively.
+ G1 = poly([0],'G1');
+ G = roots(G1*(1+0.01)-146/(1.03*(400-331.5)));
+ printf("\n Mass flow rate of inlet air = %.2f kg/secs",G);
+ printf("\n Mass flow rate of dry air ,Ga = %.2f kg/secs",G/1.01);
+ printf("\n the humidity of the outlet air H2 = %.4f kg/kg",0.01+0.0508/2.05);
+
+//At a dry bulb temperature of 331.5 K, with a humidity of 0.0347 kg/kg, the wet-bulb temperatureof the outlet air, from Figure 13.4 in Volume 1, is 312 K, the same as the inlet, which is the case for adiabatic drying.
+
+//The dryer diameter is then found from the allowable mass velocity of the air and the entering air flow and for a mass velocity of 0.95 kg/m^2.secs, the cross sectional area of the dryer is
+printf("\n The cross sectional area of the dryer is %.2f m^2",2.07/0.95);
+printf("\n The equivalent diameter of the dryer = %.2f m",[(4*2.18)/%pi]^0.5);
+
+//With a constant drying temperature of 312 K:
+ //at the inlet
+ deltaT1 = 400-312; //inlet temperature is in deg K
+ //at the outlet
+ deltaT2 = 331.5-312; //outlet temperature is in deg K
+ Tlogmean = (deltaT1 - deltaT2)/log(deltaT1/deltaT2);
+ printf("\n Logarithmic mean temperature difference = %.1f deg K",Tlogmean);
+//The length of the dryer, L is then: L = Q/(0.0625πDG^(0.67)*Tm)
+ //where D (m) is the diameter
+ //and G(kg/m^2.secs) is the air mass velocity.
+ L = 146/[0.0625*(%pi)*1.67*(0.95)^(0.67)*45.5];
+ printf("\n The length of the dryer = %.1f m",L);
+ printf("\n Length/diameter ratio = %d ",10.1/1.67);
+
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diff --git a/542/CH16/EX16.6/Example_16_6.sci b/542/CH16/EX16.6/Example_16_6.sci
new file mode 100755
index 000000000..f55ccd97b
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+++ b/542/CH16/EX16.6/Example_16_6.sci
@@ -0,0 +1,41 @@
+clear;
+clc;
+printf("\n Example 16.6");
+H = 0.036; //Humidity is in kg/kg at 811 K
+//Taking R as 90 per cent and P as 101.3 kN/m2, then, for assumed values of Tb of 321, 333 and 344 K
+ //Pw = 13,20 and 32 kN/m2, respectively
+ //G = 27.8, 12.9 and 6.02 kg/s, respectively.
+
+//for Tb = 321, 333 and 344 K,
+//G = 7.16, 7.8 and 7.54 kg/s respectively.
+Tb = [321 333 344];
+G1 = [27.8 12.9 6.02]; //Temperature is in kelvins
+G = [7.16 7.8 7.54]; //flow rate in kg/secs
+plot2d(Tb,G,style=3);
+plot2d(Tb,G1,style=2);
+xtitle("Temperature vs Flow rate","Temperature Tb(K)","Flow rate G(kg/secs)");
+
+
+//Plotting G against Tb for each equation on the same axis, then
+Go = 8.3; //Gas flow rate is in kg/secs
+Tb = 340; //temperature is in Kelvins
+uf = 0.61; //velocity is in m/secs
+
+D = sqrt(340*(8.3+(1.58*1.26))/(278*0.61));
+printf("\n D = %.2f m",D);
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