{ "metadata": { "name": "", "signature": "sha256:8d95c094e950bc8cd1f4bbc97c09344d22cf81b1ba4d6101a144be7a5e1e83dc" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter13-thermodynamic relations" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example2-pg284" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "#calculate entropy wrt pressures and volume wrt temerature\n", "##initialisation of variables\n", "S1= 6.539 ##kJ/kg K\n", "S2= 6.7664 ##kJ/kg K\n", "v1= 0.10976 ##m^3\n", "v2= 0.08700 ##m^3\n", "P= 3. ##Mpa\n", "P1= 2. ##Mpa\n", "T= 350. ##K\n", "T1= 250. ##K\n", "S3= 3.1741 ##kJ/kg K\n", "S4= 3.2071 ##kJ/kg K\n", "P2= 30. ##Mpa\n", "P3= 20. ##Mpa\n", "v3= 0.0014217 ##m^3\n", "v4= 0.0012860 ##m^3\n", "T2= 320. ##K\n", "T3= 280. ##K\n", "##CALCULATIONS\n", "r= (S1-S2)/(P*10*10*10-P1*10*10*10)\n", "r1= (v1-v2)/(T-T1)\n", "R= (S3-S4)/(P2*10*10*10-P3*10*10*10)\n", "R1= (v3-v4)/(T2-T3)\n", "##RESULTS\n", "print'%s %.7f %s'% ('entropy wrt pressre=',r,'kJ/kg K kpa')\n", "print'%s %.e %s'% ('entropy wrt pressre=',R,'kJ/kg K kpa')\n", "print'%s %.7f %s'% ('volume wrt temperature=',r1,'m^3/kg K ')\n", "print'%s %.2e %s'% ('volume wrt temperature=',R1,'m^3/kg K ')\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "entropy wrt pressre= -0.0002274 kJ/kg K kpa\n", "entropy wrt pressre= -3e-06 kJ/kg K kpa\n", "volume wrt temperature= 0.0002276 m^3/kg K \n", "volume wrt temperature= 3.39e-06 m^3/kg K \n" ] } ], "prompt_number": 6 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example3-pg286" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "#saturation pressure\n", "##initialisation of variables\n", "hfg= 2406.7 ##kJ/kg\n", "Psat40= 7.384 ##kPa\n", "R= 8.314 ##J/mol K\n", "T= 40. ##C\n", "T1= 50. ##C\n", "M= 18.##kg\n", "##CALCULATIONS\n", "Psat50= Psat40*math.e**((hfg*M/R)*((1/(273.15+T))-(1/(273.15+T1))))\n", "##RESULTS\n", "print'%s %.3f %s' %('Saturation pressure=',Psat50,'kPa')\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Saturation pressure= 12.357 kPa\n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example4-pg287" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "#calcualte lowest temprature\n", "##initialisation of variables\n", "W= 800. ##N\n", "A= 0.4 ##cm^2\n", "p= 0.611 ##Mpa\n", "P1= 0.1 ##Mpa\n", "T= 0.01 ##C\n", "vs= 0.0010908 ##m^3/kg\n", "hs= -333.40 ##kJ/kg\n", "vf= 0.0010002 ##m^3/kg\n", "hf= 0 ##kJ/kg\n", "vg= 206.14 ##m^3/kg\n", "hg= 2501.4 ##kJ/kg\n", "##CALCULATIONS\n", "P2= P1+(W/A)*math.pow(10,(4-6))\n", "dT= (273.15++T)*(vf-vs)*(P2*10*10*10-p)/(0-hs)\n", "Tmin= dT+T\n", "##RESULTS\n", "print'%s %.2f %s'% ('lowest temperature=',Tmin,'C')\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "lowest temperature= -1.48 C\n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example7-pg292" ] }, { "cell_type": "code", "collapsed": false, "input": [ "import math\n", "#calculate volume exapansion coefficent and isothermal compressibilitiy and isotherma modulus of elasticity\n", "##initialisation of variables\n", "vi= 0.0009992 ##m^3\n", "T= 60. ##C\n", "T1= 20. ##C\n", "T2= 40. ##C\n", "vi1= 0.0010042 ##m^3\n", "vi2= 0.0009886 ##m^3\n", "v= 0.000951 ##m^3\n", "v1= 0.0009992 ##m^3\n", "v2= 0.0009956 ##m^3\n", "##CALCULATIONS\n", "B= (vi1-vi2)/(vi*(T-T1))\n", "Kt= (v1-v2)/(v*(T2-T1))\n", "Et= 1/Kt\n", "##RESULTS\n", "print'%s %.2e %s'% ('volume exapansion coefficient=',B,'L/s')\n", "print'%s %.3e %s'% ('isothermal compressibility=',Kt,'Mpa')\n", "print'%s %.f %s'% ('isothermal modulus of elasticity=',Et,'Mpa')\n", "\n", "\n", "##ANSWER FOR Et GIVEN IN THE TEXTBOOK IS WRONG\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "volume exapansion coefficient= 3.90e-04 L/s\n", "isothermal compressibility= 1.893e-04 Mpa\n", "isothermal modulus of elasticity= 5283 Mpa\n" ] } ], "prompt_number": 4 } ], "metadata": {} } ] }