{ "metadata": { "name": "", "signature": "" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter6, Steam" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex1, page 346" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from math import pi, cos, sin, atan, sqrt, acos\n", "\n", "#initialisation of variables\n", "c=400.0 #steam speed in m/s\n", "alpla=12.0 #angle in degrees\n", "cwo=0\n", "pi=(22.0/7)\n", "#CALCULATIONS\n", "u=c*cos(12*(pi/180))/2\n", "cwi=c*cos(12*(pi/180))\n", "cfi=c*sin(12*(180/pi))\n", "thetha=atan(cfi/(cwi-u))*(pi/180)\n", "cro=sqrt((cfi)**2+(cwi-u)**2)\n", "phi=acos(u/cro)*(180/pi)\n", "wo=(cwi-cwo)*u\n", "ke=(c)**2/2\n", "eff=wo/ke\n", "#RESULTS\n", "print ' blade efficiency is %2f'%eff" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ " blade efficiency is 0.956738\n" ] } ], "prompt_number": 10 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex2, page 349" ] }, { "cell_type": "code", "collapsed": false, "input": [ "\n", "from math import asin\n", "#initialisation of variables\n", "hd=159 #heat drop in kj/kg\n", "eff=0.89 #and its corresponding efficiency is mentioned\n", "ra=0.4 #ratio of blade speed to steam speed\n", "sp=3000 #rotational speed of an impulse turbine wheel in revolutions\n", "a=20 #angle is 20 degrees\n", "beff=0.76 #blade efficiency\n", "cwo=5.4 #m/s\n", "pi=(22/7)\n", "bvc=0.82 #blade velocity coefficient\n", "m=15 #mass is 15 kgs\n", "#CALCULATIONS\n", "ci=44.72*sqrt(eff*hd)\n", "u=ci*ra\n", "dm=(60*u)/(sp*0.3184)\n", "cfi=ci*sin(20*(pi/180))\n", "cwi=ci*cos(20*(pi/180))\n", "cri=sqrt((cwi-u)**2+(cfi)**2)\n", "cro=bvc*cri\n", "x=(beff*(ci)**2)/(2*u) #x=cwi-cwo\n", "theta=atan((cfi/(cwi-u)))*(180/pi)\n", "cfo=sqrt((cro)**2-(cwo+u)**2)\n", "co=sqrt((cwo)**2+(cfo)**2)\n", "bet=(asin(cfo/co))*(180/pi)\n", "pd=(m*x*u)/1000\n", "re=hd-(pd/15)\n", "phi=asin((cfo/cro))*(180/pi)\n", "#RESULTS\n", "print 'mean blade ring diameter is %2fm'%dm #textbook answer is wrong\n", "print ' \\npower developed is %2fkw'%(pd)\n", "print ' \\nresidual energy at out let foe friction and nozzle efficiency is %2fkw/kg'%(re )\n", "print ' \\nblade angles are %2f,%2f,%2f'%(theta,bet,phi)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "mean blade ring diameter is 13.366333m\n", " \n", "power developed is 1613.115917kw\n", " \n", "residual energy at out let foe friction and nozzle efficiency is 51.458939kw/kg\n", " \n", "blade angles are 0.000000,92.007507,35.107859\n" ] } ], "prompt_number": 15 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex3, page 352" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from __future__ import division\n", "from math import pi, tan\n", "#initialisation of variables\n", "alpha=20 #angle in degrees\n", "theta=27 #angle in degrees\n", "m=10 #kgs\n", "vs=0.4799 #specific volume in m*m*m/kg\n", "pi=(22/7)\n", "u=100 #blade speed in m/s\n", "#CALCULATIONS\n", "ci=u*tan(27*(pi/180))/(cos(20*(pi/180))*tan(27*(pi/180))-sin(20*(pi/180)))\n", "x=2*ci*cos(20*(pi/180))-u\n", "pd=m*x*u\n", "cf=ci*sin(20*(pi/180))\n", "a=(m*vs)/cf\n", "dm=sqrt(a/(0.08*pi))\n", "h=0.08*dm\n", "#RESULTS\n", "print 'power developed is %2f w'%(pd)\n", "print ' \\narea of flow is %2f m*m'%(a)\n", "print ' \\nblade height is %2f m'%(h)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "power developed is 600057.358847 w\n", " \n", "area of flow is 0.037652 m*m\n", " \n", "blade height is 0.030958 m\n" ] } ], "prompt_number": 23 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex4, page 359" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#initialisation of variables\n", "sp=1500 #rotational speed of an impulse turbine wheel in revolutions\n", "pi=(22/7)\n", "dm=1.5 #diameter in m\n", "ra=0.8 #ratio of blade speed to steam speed\n", "x=159 #x=cwi-cwo in m/s\n", "m=10 #kgs mass\n", "cf=50.4 #m*m*m/kg\n", "vs=1.159 #\n", "#CALCULATIONS\n", "u=(pi*dm*sp)/60\n", "ci=u/ra\n", "pd=(m*x*u)/1000\n", "a=(m*vs)/cf\n", "h=a/(pi*dm)\n", "#RESULTS\n", "print 'power developed for steam flow is %2f kw'%(pd)\n", "print ' \\nheight of the blade is %2f m'%(h)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "power developed for steam flow is 187.392857 kw\n", " \n", "height of the blade is 0.048779 m\n" ] } ], "prompt_number": 27 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex5, page 365" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#initialisation of variables\n", "u=170 #blade velocity in m/s\n", "ra=0.2 #ratio of blade speed to steam speed\n", "cril=696 #m/s\n", "co1=0.84 #velocity coefficient \n", "co2=0.87 #velocity coefficient\n", "co3=0.90 #velocity coefficient\n", "cri2=232 #m/s\n", "#CALCULATIONS\n", "ci=u/ra\n", "crol=cril*co1\n", "ci2=crol*co2\n", "cro2=cri2*co3\n", "wd=(1176+344)*u*10**-3\n", "beff=wd*1000*2/(ci**2)\n", "#RESULTS\n", "print 'work developed in the blade is %2f kj/kg'%(wd)\n", "print ' \\nblading efficiency is %2f'%(beff)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "work developed in the blade is 258.400000 kj/kg\n", " \n", "blading efficiency is 0.715294\n" ] } ], "prompt_number": 30 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex6, page 368" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#initialisation of variables\n", "u=250 #blade speed in m/s\n", "theta=80 #angle in degrees\n", "alpha=20 #angle in degrees\n", "oed=786.7 #overall enthalpic drop in kj/kg\n", "sp=3000 #rotational speed of an impulse turbine wheel in revolutions\n", "p=6000 #power developed in kw\n", "rf=1.04 #reheat factor\n", "ie=2993.4 #kj/kg\n", "vs=9.28 #m*m*m/kg\n", "pi=(22/7)\n", "#CALCULATIONS\n", "ci=(u*sin(100*(pi/180)))/sin(60*(pi/180))\n", "x=(2*ci*cos(20*(pi/180)))-u #x=cwi-cwo\n", "wd=x*u*10**-3\n", "ed=wd*10\n", "teff=ed/oed\n", "seff=teff/rf\n", "m=p/ed\n", "ae=ie-ed\n", "cf=ci*sin(20*(pi/180))\n", "a=(m*vs)/cf\n", "dm=(60*u)/(pi*sp)\n", "h=a/(pi*dm)\n", "#RESULTS\n", "print 'enthalpy drop is %2f kj/kg'%(ed)\n", "print ' \\nturbine efficiency is %2f'%(teff)\n", "print ' \\nstage efficiency is %2f'%(seff)\n", "print ' \\nmass flow of steam is %2f kg/s'%(m)\n", "print ' \\nblade height us %2f m'%(h)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "enthalpy drop is 710.164887 kj/kg\n", " \n", "turbine efficiency is 0.902714\n", " \n", "stage efficiency is 0.867994\n", " \n", "mass flow of steam is 8.448742 kg/s\n", " \n", "blade height us 0.161268 m\n" ] } ], "prompt_number": 32 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Ex7, page 371" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#initialisation of variables\n", "x1=3025 # according to 20 bar pressure and 300 degrees temp\n", "x2=2262 #according to 20 bar pressure and 300 degrees temp\n", "x3=2039 #according to 20 bar pressure and 300 degrees temp\n", "x4=2896 #according to 20 bar pressure and 300 degrees temp\n", "x5=2817 #according to 20 bar pressure and 300 degrees temp\n", "x6=2728 #according to 20 bar pressure and 300 degrees temp\n", "x7=2699 #according to 20 bar pressure and 300 degrees temp\n", "x8=2592 #according to 20 bar pressure and 300 degrees temp\n", "x9=2525 #according to 20 bar pressure and 300 degrees temp\n", "x10=2430 #according to 20 bar pressure and 300 degrees temp\n", "x11=2398 #according to 20 bar pressure and 300 degrees temp\n", "x12=2262 #according to 20 bar pressure and 300 degrees temp\n", "x13=2192 #according to 20 bar pressure and 300 degrees temp\n", "#CALCULATIONS\n", "ieff=(x1-x2)/(x1-x3)\n", "feff=(x1-x4)/(x1-x5)\n", "seff=(x4-x6)/(x4-x7)\n", "teff=(x6-x8)/(x6-x9)\n", "oeff=(x8-x10)/(x8-x11)\n", "yeff=(x10-x12)/(x10-x13)\n", "ced=(x1-x5)+(x4-x7)+(x6-x9)+(x8-x11)+(x10-x13)\n", "rf=ced/(x1-x3)\n", "#RESULTS\n", "print 'cumulative enthaloy drop is %.f'%(ced)\n", "print ' \\nreheat factor is %0.2f'%(rf)" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "cumulative enthaloy drop is 1040\n", " \n", "reheat factor is 1.05\n" ] } ], "prompt_number": 35 } ], "metadata": {} } ] }