initial commit / add all books

1 files changed, 68 insertions, 0 deletions

diff --git a/2873/CH8/EX8.15/Ex8_15.sce b/2873/CH8/EX8.15/Ex8_15.sce
new file mode 100755
index 000000000..c3c13be99
--- /dev/null
+++ b/2873/CH8/EX8.15/Ex8_15.sce
@@ -0,0 +1,68 @@
+// Display mode

+mode(0);

+// Display warning for floating point exception

+ieee(1);

+clear;

+clc;

+disp("Engineering Thermodynamics by Onkar Singh Chapter 8 Example 15")

+disp("Let us carry out analysis for 1 kg of steam generated in boiler.")

+disp("Enthalpy at inlet to HPT,h2=2960.7 KJ/kg,s2=6.3615 KJ/kg K")

+h2=2960.7;

+s2=6.3615;

+disp("state at 3  i.e. exit from HPT can be identified by s2=s3=6.3615 KJ/kg K")

+s3=s2;

+disp("Let dryness fraction be x3,s3=6.3615=sf at 2 bar+x3*sfg at 2 bar")

+disp("so x3=(s3-sf)/sfg")

+disp("from stem tables,at 2 bar,sf=1.5301 KJ/kg K,sfg=5.5970 KJ/kg K")

+sf=1.5301;

+sfg=5.5970;

+x3=(s3-sf)/sfg

+x3=0.863;//approx.

+disp("h3=2404.94 KJ/kg")

+h3=2404.94;

+disp("If one kg of steam is generated in bolier then at exit of HPT,0.5 kg goes into process heater and 0.5 kg goes into separator")

+disp("mass of moisture retained in separator(m)=(1-x3)*0.5 kg")

+m=(1-x3)*0.5

+disp("Therefore,mass of steam entering LPT(m_LP)=0.5-m kg")

+m_LP=0.5-m

+disp("Total mass of water entering hot well at 8(i.e. from process heater and drain from separator)=(0.5+0.685)=0.5685 kg")

+disp("Let us assume the temperature of water leaving hotwell be T oc.Applying heat balance for mixing;")

+disp("(0.5685*4.18*90)+(0.4315*4.18*40)=(1*4.18*T)")

+disp("so T=((0.5685*4.18*90)+(0.4315*4.18*40))/4.18 in degree celcius")

+T=((0.5685*4.18*90)+(0.4315*4.18*40))/4.18

+disp("so temperature of water leaving hotwell=68.425 degree celcius")

+disp("Applying heat balanced on trap")

+disp("0.5*h7+0.0685*hf at 2 bar=(0.5685*4.18*90)")

+disp("so h7=((0.5685*4.18*90)-(0.0685*hf))/0.5 in KJ/kg")

+disp("from steam tables,at 2 bar,hf=504.70 KJ/kg")

+hf=504.70;

+h7=((0.5685*4.18*90)-(0.0685*hf))/0.5

+disp("Therefore,heat transferred in process heater=0.5*(h3-h7)in KJ/kg steam generated")

+0.5*(h3-h7)

+disp("so heat transferred per kg steam generated=1023.175 KJ/kg steam generated")

+disp("For state 10 at exit of LPT,s10=s3=s2=6.3615 KJ/kg K")

+s10=s3;

+disp("Let dryness fraction be x10")

+disp("s10=6.3615=sf at 0.075 bar+x10*sfg at 0.075 bar")

+disp("from steam tables,at 0.075 bar,sf=0.5764 KJ/kg K,sfg=7.6750 KJ/kg K")

+sf=0.5764;

+sfg=7.6750;

+disp("so x10=(s10-sf)/sfg")

+x10=(s10-sf)/sfg

+x10=0.754;//approx.

+disp("h10=hf at 0.075 bar+x10*hfg at 0.075 bar")

+disp("from steam tables,at 0.075 bar,hf=168.79 KJ/kg,hfg=2406.0 KJ/kg")

+hf=168.79;

+hfg=2406.0;

+disp("so h10=hf+x10*hfg in KJ/kg ")

+h10=hf+x10*hfg 

+disp("net work output,neglecting pump work per kg of steam generated,")

+disp("w_net=(h2-h3)*1+0.4315*(h3-h10) in KJ/kg steam generated")

+w_net=(h2-h3)*1+0.4315*(h3-h10) 

+disp("Heat added in boiler per kg steam generated,q_add=(h2-h1)in KJ/kg")

+q_add=(h2-4.18*68.425)

+disp("thermal efficiency=w_net/q_add")

+w_net/q_add

+disp("in percentage")

+w_net*100/q_add

+disp("so Thermal efficiency=27.58%")