{ "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "# Chapter 03:Work and Heat Transfer" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Ex3.1:pg-54" ] }, { "cell_type": "code", "execution_count": 4, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "\n", " Example 3.1\n", "\n", " The amount of work done upon the atmosphere by the balloon is 50.6625 kJ\n" ] } ], "source": [ "dV = 0.5 # Change in volume in m**3\n", "\n", "P = 101.325e03 # Atmospheric pressure in N/m**2\n", "\n", "Wd = P*dV # Work done in J\n", "\n", "print \"\\n Example 3.1\"\n", "\n", "print \"\\n The amount of work done upon the atmosphere by the balloon is \",Wd/1e3,\" kJ\",\n", "\n", "#The answers vary due to round off error\n", "\n", "\n", "\n" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Ex3.2:pg-55" ] }, { "cell_type": "code", "execution_count": 5, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "\n", " Example 3.2\n", "\n", " The displacement work done by the air is 60.795 kJ\n" ] } ], "source": [ "dV = 0.6 # Volumetric change in m**3\n", "\n", "P = 101.325e03 # Atmospheric pressure in N/m**2\n", "\n", "Wd = P*dV # Work done in J\n", "\n", "print \"\\n Example 3.2\"\n", "\n", "print \"\\n The displacement work done by the air is \",Wd/1e3 ,\" kJ\"\n", "\n", "#The answers vary due to round off error\n", "\n" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Ex3.3:pg-55" ] }, { "cell_type": "code", "execution_count": 8, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "\n", " Example 3.3\n", "\n", " The net work transfer for the system is -57.19 kJ\n" ] } ], "source": [ "# Given that\n", "\n", "T = 1.275 # Torque acting against the fluid in mN\n", "\n", "N = 10000 # Number of revolutions\n", "\n", "W1 = 2*math.pi*T*1e-3*N # Work done by stirring device upon the system\n", "\n", "P = 101.325e03 # Atmospheric pressure in kN/m**2\n", "\n", "d = 0.6 # Piston diameter in m\n", "\n", "A = (math.pi/4)*(d)**2 # Piston area in m\n", "\n", "L = 0.80 # Displacement of diameter in m\n", "\n", "W2 = (P*A*L)/1000 # Work done by the system on the surroundings i KJ\n", "\n", "W = -W1+W2 # net work transfer for the system\n", "print \"\\n Example 3.3\"\n", "print \"\\n The net work transfer for the system is \",round(W,2) ,\" kJ\"\n", "#The answers vary due to round off error\n", "\n" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Ex3.4:pg-56" ] }, { "cell_type": "code", "execution_count": 9, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "\n", " Example 3.4\n", "\n", " The rate of work transfer from gas to the piston is 24383.7855401 kW\n" ] } ], "source": [ "# Given that\n", "\n", "ad = 5.5e-04 # Area of indicator diagram in m**2\n", "\n", "ld = 0.06 # Length of diagram in m\n", "\n", "k = 147 # Spring value in MPa/m\n", "\n", "w = 150 # Speed of engine in revolution per minute\n", "\n", "L = 1.2 # Stroke of piston in m\n", "\n", "d = 0.8 # Diameter of the cylinder in m\n", "\n", "A = (math.pi/4)*(0.8**2) # Area of cylinder\n", "\n", "Pm = (ad/ld)*k # Effective pressure in MPa\n", "\n", "W1 = Pm*L*A*w # Work done in 1 minute MJ\n", "\n", "W = (12*W1)/60 # The rate of work transfer gas to the piston in MJ/s\n", "\n", "\n", "\n", "print \"\\n Example 3.4\"\n", "\n", "print \"\\n The rate of work transfer from gas to the piston is \",W*1e3 ,\" kW\"\n", "\n", "#The answers vary due to round off error\n", "\n" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Ex3.5:pg-57" ] }, { "cell_type": "code", "execution_count": 10, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "\n", " Example 3.5\n", "\n", " Rating of furnace would be 2.17163371599 *1e3 kW\n", "\n", " Diameter of furnace is 1.0 m\n", "\n", " Length of furnace is 2.0 m\n" ] } ], "source": [ "#Given that\n", "\n", "m = 5 # mass flow rate in tones/h\n", "\n", "Ti = 15 # Initial temperature in degree Celsius\n", "\n", "tp = 1535 # Phase change temperature in degree Celsius\n", "\n", "Tf = 1650 # Final temperature in degree Celsius\n", "\n", "Lh = 270 # Latent heat of iron in kJ/Kg\n", "\n", "ml = 29.93 # Specific heat of iron in liquid phase in kJ/Kg\n", "\n", "ma = 56 # Atomic weight of iron\n", "\n", "sh = 0.502 # Specific heat of iron in solid phase in kJ/Kg\n", "\n", "d = 6900 # Density of molten metal in kg/m**3\n", "\n", "n=0.7 # furnace efficiency\n", "\n", "l_d_ratio = 2 # length to diameter ratio\n", "\n", "print \"\\n Example 3.5\"\n", "\n", "h1 = sh*(tp-Ti) # Heat required to raise temperature\n", "\n", "h2 = Lh # Heat consumed in phase change\n", "\n", "h3 = ml*(Tf-tp)/ma # Heat consumed in raising temperature of molten mass\n", "\n", "h = h1+h2+h3 # Heat required per unit mass\n", "\n", "Hi = h*m*1e3 # Ideal heat requirement\n", "\n", "H = Hi/(n*3600) # Actual heat requirement\n", "\n", "V = (3*m)/d # Volume required in m**3\n", "\n", "d = (4*V/(math.pi*l_d_ratio))**(1/3) # Diameter of furnace \n", "\n", "l = d*l_d_ratio # Length of furnace\n", "\n", "print \"\\n Rating of furnace would be \",H/1e3 ,\" *1e3 kW\"\n", "\n", "print \"\\n Diameter of furnace is \",d ,\" m\"\n", "\n", "print \"\\n Length of furnace is \",l ,\" m\"\n", "\n", "#The answer provided in the textbook is wrong\n", "\n" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Ex3.6:pg-57" ] }, { "cell_type": "code", "execution_count": 15, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "\n", " Example 3.6\n", "\n", " Rate at which aluminium can be melted is 5.39 tonnes/h\n", "\n", " Mass of aluminium that can be held in furnace is 5.232 tonnes\n" ] } ], "source": [ "# Given that\n", "\n", "SH = 0.9 # Specific heat of aluminium in solid state in kJ/kgK \n", "\n", "L = 390 # Latent heat in kJ/kg\n", "\n", "aw = 27 # Atomic weight\n", "\n", "D = 2400 # Density in molten state in kg/m**3\n", "\n", "Tf = 700 # Final temperature in degree Celsius\n", "\n", "Tm = 660 # Melting point of aluminium in degree Celsius\n", "\n", "Ti = 15 # Initial temperature in degree Celsius\n", "\n", "HR = SH*(Tm-Ti)+L+(29.93/27)*(Tf-Tm) # Heat requirement\n", "\n", "HS = HR/0.7 # Heat supplied\n", "\n", "RM = 2.17e3*3600/HS # From the data of problem 3.7\n", "\n", "V = 2.18 # Volume in m**3\n", "\n", "M = V*D\n", "\n", "print \"\\n Example 3.6\"\n", "\n", "print \"\\n Rate at which aluminium can be melted is \",round(RM/1e3,2) ,\" tonnes/h\"\n", "\n", "print \"\\n Mass of aluminium that can be held in furnace is \",M/1e3 ,\"tonnes\"\n", "\n" ] } ], "metadata": { "kernelspec": { "display_name": "Python 2", "language": "python", "name": "python2" }, "language_info": { "codemirror_mode": { "name": "ipython", "version": 2 }, "file_extension": ".py", "mimetype": "text/x-python", "name": "python", "nbconvert_exporter": "python", "pygments_lexer": "ipython2", "version": "2.7.11" } }, "nbformat": 4, "nbformat_minor": 0 }