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author | priyanka | 2015-06-24 15:03:17 +0530 |
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committer | priyanka | 2015-06-24 15:03:17 +0530 |
commit | b1f5c3f8d6671b4331cef1dcebdf63b7a43a3a2b (patch) | |
tree | ab291cffc65280e58ac82470ba63fbcca7805165 /2657/CH3/EX3.5/Ex3_5.sce | |
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initial commit / add all books
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diff --git a/2657/CH3/EX3.5/Ex3_5.sce b/2657/CH3/EX3.5/Ex3_5.sce new file mode 100755 index 000000000..920b01c13 --- /dev/null +++ b/2657/CH3/EX3.5/Ex3_5.sce @@ -0,0 +1,44 @@ +//Effect of molecular contraction +clc,clear +//Given: +r=7 //Compression ratio +CV=44000 //Calorific value of the fuel in kJ/kg +A_F=13.67 //Air fuel ratio of the mixture +cv=0.718 //Specific heat at constant volume in kJ/kgK +n=1.3 //Polytropic index +P1=1,T1=67+273 //Pressure and temperature at the beginning in bar and K +//Solution: +//Refer fig 3.22 +C=12 //Atomic mass of Carbon(C) +H=1 //Atomic mass of Hydrogen(H) +O=16 //Atomic mass of Oxygen(O) +p=23 //Percentage of oxygen in air by mass +//Stoichiometric equation of combustion of fuel (C6H14) +// [C6H14] + x[O2] = y[CO2] + z[H2O] +//Equating coefficients +x=9.5,y=6,z=7 //Coefficients of stoichiometric equation +A_F_g=x*2*O/(6*C+14*H)*100/p //Gravimetric air fuel ratio +MS=A_F_g/A_F*100 //Actual mixture strength in percent +//Combustion is incomplete +//Stoichiometric equation of incomplete combustion of fuel (C6H14) +// MS/100[C6H14] + x[O2] = a[CO2] + b[CO] + c[H2O] +//Equating coefficients +a=4.39,b=2.36,c=7.87 //Coefficients of stoichiometric equation +//Stoichiometric equation of combustion of fuel (C6H14) by adding Nitrogen +// MS/100[C6H14] + x[O2] + x*79/21[N2] = a[CO2] + b[CO] + c[H2O] + x*79/21[N2] +m1=MS/100+x+x*79/21 //Moles before combustion +m2=a+b+c+x*79/21 //Moles after combustion +Me=(m2-m1)/m1*100 //Molecular expansion in percent +T2=T1*r^(n-1) //Temperature at 2 in K +m_c=A_F+1 //Mass of charge in kg +T3=CV/(m_c*cv)+T2 //Temperature at 3 in K +T3=round(T3) +P3=P1*r*(T3/T1) //Pressure at 3 in bar (printing error) +//Temperature and pressure considering molecular expansion +T3!=T3 //Temperature remains same at 3 in K +P3!=P3*m2/m1 //Pressure at 3 in bar +//Results: +printf("\n\t The molecular expansion = %.2f percent\n",Me) +printf("\n (a)Without considering the molecular contraction\n\t The maximum pressure, P3 = %.2f bar\n\t The maximum temperature, T3 = %.0f K",P3,T3) +printf("\n (b)Considering the molecular contraction\n\t The maximum pressure, P3 = %.2f bar\n\t The maximum temperature, T3 = %.0f K",P3!,T3!) +//Answer in the book is wrong |