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diff --git a/Engineering_Thermodynamics/ch18.ipynb b/Engineering_Thermodynamics/ch18.ipynb new file mode 100755 index 00000000..808ecda7 --- /dev/null +++ b/Engineering_Thermodynamics/ch18.ipynb @@ -0,0 +1,554 @@ +{ + "metadata": { + "name": "", + "signature": "sha256:9e53418f9e4cdd211f20a8f37b3c55eb0a17f05c8100d8c18f420c262cc67c0c" + }, + "nbformat": 3, + "nbformat_minor": 0, + "worksheets": [ + { + "cells": [ + { + "cell_type": "heading", + "level": 1, + "metadata": {}, + "source": [ + "Chapter 18 : Gas Compressors" + ] + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 18.1 Page No : 723" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "import math \n", + "\n", + "# Variables\n", + "T2 = 488.\n", + "T1 = 298.; n = 1.3; R =8314./44;\n", + "\n", + "# Calculation and Results\n", + "rp = (T2/T1)**(n/(n-1));\n", + "print \"Pressure ratio is\",round(rp,2)\n", + "\n", + "b = 0.12; \t\t\t# Bore of compressor\n", + "L = 0.15; \t\t\t# Stroke of compressor\n", + "V1 = (math.pi/4)*(b)**2*L ; \n", + "P1 = 120e03; \t\t\t# in kPa\n", + "W = ((n*P1*V1)/(n-1))*(((rp)**((n-1)/n))-1);\n", + "P = (W*1200*0.001)/60 ; \n", + "print \"Indicated power is\",round(P,2),\"kW\"\n", + "print \"Shaft power is\",round((P/0.8),1),\"kW\"\n", + "\n", + "V1_dot = V1*(1200./60);\n", + "m_dot = (P1*V1_dot)/(R*T1);\n", + "print \"Mass flow rate is\",round(m_dot,4),\"kg/s\"\n", + "\n", + "rp_1 = rp**2;\n", + "print \"Pressure ratio when second stage is added is\",round(rp_1,1)\n", + "\n", + "V2 = (1./rp)**(1./n)*V1;\n", + "print \"Volume derived per cycle is V2\",round(V2,5),\"m3\"\n", + "\n", + "d = math.sqrt((V2*4)/(L*math.pi));\n", + "print \"Second stage bore would be\",round((d*1000),0),\"mm\"\n" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Pressure ratio is 8.48\n", + "Indicated power is 11.25 kW\n", + "Shaft power is 14.1 kW\n", + "Mass flow rate is 0.0723 kg/s\n", + "Pressure ratio when second stage is added is 71.9\n", + "Volume derived per cycle is V2 0.00033 m3\n", + "Second stage bore would be 53.0 mm\n" + ] + } + ], + "prompt_number": 7 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 18.2 Page No : 724" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "import math \n", + "\n", + "# Variables\n", + "P1 = 101.3e03\n", + "P4 = P1; \t\t\t# in Pa\n", + "P2 = 8*P1\n", + "P3 = P2;\n", + "T1 = 288.\n", + "Vs = 2000.;\n", + "V3 = 100.\n", + "Vc = V3;\n", + "\n", + "# Calculation and Results\n", + "V1 = Vs + Vc ;\n", + "n = 1.25\n", + "R = 287.;\n", + "V4 = ((P3/P4)**(1./n))*V3;\n", + "W = ((n*P1*(V1-V4)*1e-06)/(n-1))*(((P2/P1)**((n-1)/n))-1);\n", + "P = (W*800*0.001)/60 ; \n", + "print \"Indicated poer is\",round(P,2),\"kW\"\n", + "print \"Volumetric efficiency is\",round((100*(V1-V4)/Vs),1),\"%\"\n", + "\n", + "m = (P1*(V1-V4)*1e-06)/(R*T1);\n", + "m_dot = m*800;\n", + "print \"Mass flow rate is\",round(m_dot,2),\"kg/min\"\n", + "\n", + "FAD = (V1-V4)*1e-06*800;\n", + "print \"Free air delivery is\",round(FAD,2),\"m3/min\"\n", + "\n", + "Wt = P1*(V1-V4)*1e-06*math.log(P2/P1);\n", + "n_isothermal = (Wt*800*0.001)/(P*60);\n", + "print \"Isothermal efficiency is\",round(100*n_isothermal,1),\"%\"\n", + "\n", + "ip = P/0.85;\n", + "print \"Input power is\",round(ip,2),\"kW\"\n" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Indicated poer is 5.48 kW\n", + "Volumetric efficiency is 78.6 %\n", + "Mass flow rate is 1.54 kg/min\n", + "Free air delivery is 1.26 m3/min\n", + "Isothermal efficiency is 80.6 %\n", + "Input power is 6.44 kW\n" + ] + } + ], + "prompt_number": 2 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 18.3 Page No : 725" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "import math \n", + "\n", + "# Variables\n", + "P1 = 1.; \n", + "P3 = 9.;\n", + "\n", + "# Calculation\n", + "P2 = math.sqrt(P1*P3);\n", + "T1 = 300.; \n", + "cp = 1.005;\n", + "R = 0.287; n = 1.3;\n", + "W = ((2*n*R*T1)/(n-1))*((P2/P1)**((n-1)/n)-1);\n", + "T2 = T1*(P2/P1)**((n-1)/n);\n", + "H = cp*(T2-T1);\n", + "\n", + "# Results\n", + "print \"Heat rejected to the intercooler is\",round(H,2),\"kJ/kg\"\n", + "\n", + "# rounding off error is there." + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Heat rejected to the intercooler is 87.0 kJ/kg\n" + ] + } + ], + "prompt_number": 4 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 18.4 Page No : 726" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "import math \n", + "\n", + "# Variables\n", + "P1 = 1.013\n", + "P4 = 80.;\n", + "P2 = math.sqrt(P1*P4);\n", + "V_dot = 4./60; \t\t\t# in m3/s\n", + "n = 1.25;\n", + "n_mech = 0.75;\n", + "\n", + "# Calculation\n", + "W_dot = ((2*n)/(n-1))*((P1*100*V_dot)/n_mech)*((P2/P1)**((n-1)/n)-1);\n", + "N = 250.;\n", + "L = (3*60.)/(2*N); \t\t\t# Stroke length of piston in m\n", + "Vlp = 4/N;\n", + "n_vol = 0.8;\n", + "Dlp = math.sqrt((Vlp*4)/(n_vol*L*math.pi));\n", + "Dhp = Dlp*math.sqrt(P1/P2);\n", + "\n", + "# Results\n", + "print \"Minimum power required is\",round(W_dot,2),\"kW\"\n", + "print \"Stroke of the compressor is\",L*100,\"cm\"\n", + "print \"Bore of high pressure compressure is\",round((Dhp*100),2),\"cm\"\n", + "print \"Bore of lo pressure compressure is\",round((Dlp*100),1),\"cm\"\n" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Minimum power required is 49.34 kW\n", + "Stroke of the compressor is 36.0 cm\n", + "Bore of high pressure compressure is 8.92 cm\n", + "Bore of lo pressure compressure is 26.6 cm\n" + ] + } + ], + "prompt_number": 11 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 18.5 Page No : 727" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "\n", + "# Variables\n", + "V12 = 0.4; \t\t\t# V12 = V1./V2\n", + "T1 = 38.+273; \n", + "n = 1.3; \n", + "P3 = 112.; \t\t\t# back pressure\n", + "m = 1.25; R = 0.287;\n", + "\n", + "# Calculation\n", + "T2 = ((V12)**(n-1))*T1;\n", + "P1 = 700.; \t\t\t# in kPa\n", + "P2 = P1*(V12)**n;\n", + "V2 = (m*R*T2)/P2;\n", + "v2 = V2/m ;\n", + "A = R*T1 + R*(T1-T2)/(n-1) - P3*v2; \t\t\t# Area of indicator diagram\n", + "IO = A*0.85*m;\n", + "\n", + "# Results\n", + "print \"Indicated output is\",round(IO,2),\"kJ\"\n", + "\n" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Indicated output is 132.88 kJ\n" + ] + } + ], + "prompt_number": 12 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 18.6 Page No : 728" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "import math \n", + "\n", + "# Variables\n", + "P1 = 1.\n", + "P41 = 15.; \t\t\t# P41 = P4/P1\n", + "P21 = (P41)**(1./3);\n", + "P2 = P21*P1;\n", + "n = 1.3; \n", + "R = 0.287;\n", + "P3 = P21*P2;\n", + "P11 = P2; P12 = P1;\n", + "b = 0.45\n", + "s = 0.3; \t\t\t# Bore and stroke of cylinder\n", + "Vs = (math.pi/4)*b**2*s; \t\t\t# Swept volume of the cylinder\n", + "\n", + "# Calculation and Results\n", + "V11 = 0.05*Vs; \t\t\t# Clearance volume\n", + "V1 = V11+Vs;\n", + "V12 = V11*(P11/P12)**(1./n);\n", + "print \"Effective swept volume of the LP cylinder is\",round((V1-V12),5),\"m3\"\n", + "\n", + "T1 = 291.\n", + "T3 = T1; \n", + "T5 = T1;\n", + "P43 = P21; \t\t\t# P4/P3\n", + "T6 = T5*(P43)**((n-1)/n);\n", + "print \"Delivery temperature is\",round(T6,1),\"K\"\n", + "\n", + "P4 = 15; \t\t\t# Delivery pressure\n", + "V6_7 = (P1/P4)*(T6/T1)*(V1-V12); \t\t\t# V6-V7\n", + "print \"Volume of the air delivered\",round(V6_7,5),\"m3\"\n", + "\n", + "W = ((3*n*R*T1)/(n-1))*((P21)**((n-1)/n)-1);\n", + "print \"Work done per kg of the air is\",round(W,1),\"kJ\"\n", + "\n", + "# rounding off error is there. please check." + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Effective swept volume of the LP cylinder is 0.04532 m3\n", + "Delivery temperature is 358.4 K\n", + "Volume of the air delivered 0.00372 m3\n", + "Work done per kg of the air is 251.4 kJ\n" + ] + } + ], + "prompt_number": 5 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 18.7 Page No : 729" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "\n", + "# Variables\n", + "P1 = 1.013;\n", + "P2 = 1.5*P1;\n", + "Vs = 0.03\n", + "Va = Vs;\n", + "WD = (P2-P1)*Vs*100.;\n", + "Pi = (P1+P2)/2;\n", + "g = 1.4;\n", + "\n", + "# Calculation\n", + "Aa = ((g*P1*100*Vs)/(g-1))*((Pi/P1)**((g-1)/g)-1);\n", + "Vb = Va *(P1/Pi)**(1./g);\n", + "Ab = Vb*(P2-Pi)*100;\n", + "WR = Aa+Ab;\n", + "\n", + "# Results\n", + "print \"Work required is\",round(WR,2),\"kJ/rev\"\n" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Work required is 1.35 kJ/rev\n" + ] + } + ], + "prompt_number": 14 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 18.8 Page No : 730" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "# For Blower\n", + "import math \n", + "m_dot = 1.; \n", + "R = 0.287; \n", + "T1 = 343.;\n", + "P1 = 100.; \n", + "P2 = 2*P1; \n", + "g = 1.4;\n", + "\n", + "# Calculation and Results\n", + "V_dot = (m_dot*R*T1)/P1;\n", + "PRb = V_dot*(P2-P1);\n", + "print \"Power required by the blower is\",round(PRb,1),\"kW\"\n", + "\n", + "# For van compressor\n", + "P1v = 1.\n", + "V21 = 0.7 \t\t\t# V2/V1\n", + "P2v = P1v*(1./V12)**g;\n", + "V2_dot = 0.7;\n", + "V1_dot = 0.7*V_dot;\n", + "P3v = 2.;\n", + "PRv = (g/0.4)*P1*0.995*( (1.65/1)**(0.4/g) - 1) + 0.696*(2 - 1.65)*P1\n", + "print \"Power Required by van compressor is\",round(PRv),\"kW\"\n", + "\n" + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Power required by the blower is 98.4 kW\n", + "Power Required by van compressor is 78.0 kW\n" + ] + } + ], + "prompt_number": 9 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 18.9 Page No : 731" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "\n", + "# Variables\n", + "T1 = 283.\n", + "P21 = 2.5; \t\t\t# P2/P1\n", + "P32 = 2.1; \t\t\t# P3/P2\n", + "ns = 0.85\n", + "ma = 5.; \n", + "cp = 1.005;\n", + "\n", + "# Calculation\n", + "T2s = round(T1*(P21)**((g-1)/g),1);\n", + "T2 = round(T1 + (T2s-T1)/ns,2);\n", + "T3 = T2-50;\n", + "T4s = round(T3*(P32)**((g-1)/g),2);\n", + "T4 = T3 + (T4s-T3)/ns;\n", + "P = ma*cp*((T2-T1)+(T4-T3));\n", + "\n", + "# Results\n", + "print \"Total compressor power is\",round(P,1),\"kW\"\n", + "\n", + "# note : T4 is calculted wrongly in book. please check." + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Total compressor power is 965.1 kW\n" + ] + } + ], + "prompt_number": 13 + }, + { + "cell_type": "heading", + "level": 2, + "metadata": {}, + "source": [ + "Example 18.10 Page No : 732" + ] + }, + { + "cell_type": "code", + "collapsed": false, + "input": [ + "\n", + "# Variables\n", + "T1 = 278.\n", + "P21 = 2.5; \t\t\t# P2/P1\n", + "cp = 1.005\n", + "ns = 0.84; V2 = 120.;\n", + "\n", + "# Calculation\n", + "T2s = T1*(P21)**((g-1)/g);\n", + "T2 = T1 + (T2s-T1)/ns;\n", + "mg = 0.04*(13+1);\n", + "P = mg*cp*(T2-T1);\n", + "T02 = T2 + V2**2/(2*cp*1000);\n", + "P1 = 0.6;\n", + "P2 = P21*0.6;\n", + "P02 = P2*(T02/T2)**(g/(g-1));\n", + "\n", + "# Results\n", + "print \"Power required to drive the compressor is\",round(P,1),\"kW\"\n", + "print \"Stagnation temperature is\",round(T02,2),\"K\"\n", + "print \"Stagnation pressure is\",round(P02,3),\"bar\"\n", + "\n", + "# note : rounding off error is there. please check." + ], + "language": "python", + "metadata": {}, + "outputs": [ + { + "output_type": "stream", + "stream": "stdout", + "text": [ + "Power required to drive the compressor is 55.7 kW\n", + "Stagnation temperature is 384.21 K\n", + "Stagnation pressure is 1.602 bar\n" + ] + } + ], + "prompt_number": 15 + } + ], + "metadata": {} + } + ] +}
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