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 "worksheets": [

  {

   "cells": [

    {

     "cell_type": "heading",

     "level": 1,

     "metadata": {},

     "source": [

      "Chapter04: Analysis of Convection Heat Transfer"

     ]

    },

    {

     "cell_type": "heading",

     "level": 2,

     "metadata": {},

     "source": [

      "Ex4.1:pg-232"

     ]

    },

    {

     "cell_type": "code",

     "collapsed": false,

     "input": [

      "\n",

      "print \"Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 4 Example # 4.1 \"\n",

      "\n",

      "# Temperature of air in C is given as:\n",

      "Tinfinity = 20;\n",

      "# Temperature of surface in C is given as:\n",

      "Ts = 100;\n",

      "# Therefore avaerage temperature in degree C would be:\n",

      "Ta = (Ts+Tinfinity)/2;\n",

      "# From fig. 4.2 on page 232, it can be easily seen that (deltaT/deltaY) at\n",

      "# y=0 is -66.7 K/mm\n",

      "# From Table 28 in Appendix 2, at average temperature of air, thermal\n",

      "# conductivity in W/m-K is\n",

      "k = 0.028;\n",

      "\n",

      "#Therefore from eq. 4.1\n",

      "print \"The heat transfer coefficient is given by, as per Eq. 4.1, in W/m2K\"\n",

      "# 1000 is added to convert from mm to m\n",

      "#heat transfer coefficient in W/m2K\n",

      "hc = ((-k*(-66.7))/(Ts-Tinfinity))*1000\n",

      "print round(hc,1)\n"

     ],

     "language": "python",

     "metadata": {},

     "outputs": [

      {

       "output_type": "stream",

       "stream": "stdout",

       "text": [

        "Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 4 Example # 4.1 \n",

        "The heat transfer coefficient is given by, as per Eq. 4.1, in W/m2K\n",

        "23.3\n"

       ]

      }

     ],

     "prompt_number": 2

    },

    {

     "cell_type": "heading",

     "level": 2,

     "metadata": {},

     "source": [

      "Ex4.3:pg-259"

     ]

    },

    {

     "cell_type": "code",

     "collapsed": false,

     "input": [

      "\n",

      "print \"Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 4 Example # 4.3 \"\n",

      "\n",

      "# Width of the collector plate in ft is given:\n",

      "b = 1.0;\n",

      "# Surface temperature in F is given:\n",

      "Ts = 140.0;\n",

      "# Air temperature in F is given:\n",

      "Tinfinity = 60.0;\n",

      "# Air velocity in ft/sec is given as:\n",

      "Uinfinity = 10.0;\n",

      "# Average temperature in degree F is given as:\n",

      "T = (Ts+Tinfinity)/2;\n",

      "# Properties of air at average temperature are as follows\n",

      "\n",

      "Pr = 0.72; #Prandtl number\n",

      "k = 0.0154; # Thermal conductivity in Btu/h ft \u00b0F\n",

      "mu = 1.285*10-5;  #Viscosity in lbm/ft s\n",

      "cp = 0.24; #Specific heat in Btu/lbm \u00b0F\n",

      "rho = 0.071; #Density in lbm/ft3\n",

      "\n",

      "# Reynold''s number at x=1ft is\n",

      "Re1 = ((Uinfinity*rho)*1)/mu;\n",

      "# Reynold''s number at x=9ft is\n",

      "Re9 = ((Uinfinity*rho)*1)/mu;\n",

      "# Assuming that the critical Reynolds number is 5*10**5, the critical distance is\n",

      "#Critical Reynolds number\n",

      "Rec = 5.0*(10**5);\n",

      "#Critical distance in ft\n",

      "xc = (Rec*mu)/(Uinfinity*rho);\n",

      "\n",

      "# From Eq. 4.28, and using the data obtained, we get for part a:\n",

      "print \"Delta at x=1ft to be 0.0213ft and at x=9ft to be 0.0638ft\"\n",

      "\n",

      "# From Eq. 4.30, and using the data obtained, we get for part b:\n",

      "print \"Cfx at x=1ft to be 0.00283 and at x=9ft to be 0.000942\"\n",

      "\n",

      "# From Eq. 4.31, and using the data obtained, we get for part c:\n",

      "print \"Cfbar at x=1ft to be 0.00566 and at x=9ft to be 0.00189\"\n",

      "\n",

      "# From Eq. 4.29, and using the data obtained, we get for part d:\n",

      "print \"Tau at x=1ft to be 3.12*10**-4 lb/ft**2 and at x=9ft to be 1.04*10**-4 lb/ft**2\"\n",

      "\n",

      "# From Eq. 4.32, and using the data obtained, we get for part e:\n",

      "print \"DeltaTH at x=1ft to be 0.0237ft and at x=9ft to be 0.0712ft\"\n",

      "\n",

      "# From Eq. 4.36, and using the data obtained, we get for part f:\n",

      "print \"hcx at x=1ft to be 1.08Btu/hft**2\u00b0F and at x=9ft to be 0.359Btu/hft**2\u00b0F\"\n",

      "\n",

      "# From Eq. 4.39, and using the data obtained, we get for part g:\n",

      "print \"hcbar at x=1ft to be 2.18Btu/hft**2\u00b0F and at x=9ft to be 0.718Btu/hft**2\u00b0F\"\n",

      "\n",

      "# From Eq. 4.35, and using the data obtained, we get for part h:\n",

      "print \"q at x=1ft to be 172 Btu/h and at x=9ft to be 517 Btu/h\"\n"

     ],

     "language": "python",

     "metadata": {},

     "outputs": [

      {

       "output_type": "stream",

       "stream": "stdout",

       "text": [

        "Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 4 Example # 4.3 \n",

        "Delta at x=1ft to be 0.0213ft and at x=9ft to be 0.0638ft\n",

        "Cfx at x=1ft to be 0.00283 and at x=9ft to be 0.000942\n",

        "Cfbar at x=1ft to be 0.00566 and at x=9ft to be 0.00189\n",

        "Tau at x=1ft to be 3.12*10**-4 lb/ft**2 and at x=9ft to be 1.04*10**-4 lb/ft**2\n",

        "DeltaTH at x=1ft to be 0.0237ft and at x=9ft to be 0.0712ft\n",

        "hcx at x=1ft to be 1.08Btu/hft**2\u00b0F and at x=9ft to be 0.359Btu/hft**2\u00b0F\n",

        "hcbar at x=1ft to be 2.18Btu/hft**2\u00b0F and at x=9ft to be 0.718Btu/hft**2\u00b0F\n",

        "q at x=1ft to be 172 Btu/h and at x=9ft to be 517 Btu/h\n"

       ]

      }

     ],

     "prompt_number": 3

    },

    {

     "cell_type": "heading",

     "level": 2,

     "metadata": {},

     "source": [

      "Ex4.4:pg-275"

     ]

    },

    {

     "cell_type": "code",

     "collapsed": false,

     "input": [

      "\n",

      "print \"Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 4 Example # 4.4 \"\n",

      "\n",

      "# Length of the crankcase in m is given as\n",

      "L = 0.6;\n",

      "# Width of the crankcase in m is given as\n",

      "b = 0.2;\n",

      "# Depth of the crankcase in m is given as\n",

      "d = 0.1;\n",

      "# Surface temperature in K is given as\n",

      "Ts = 350.0;\n",

      "# Air temperature in K is given as\n",

      "Tinfinity = 276.0;\n",

      "# Air velocity in m/sec is given as\n",

      "Uinfinity = 30.0;\n",

      "# It is stated that  boundary layer is turbulent over the entire surface\n",

      "\n",

      "#Average air temperature in degree K is\n",

      "T = (Ts+Tinfinity)/2;\n",

      "# At this average temperature, we get the following for air\n",

      "rho = 1.092;#density in kg/m**3\n",

      "mu = 0.000019123;#vismath.cosity in SI units\n",

      "Pr = 0.71;#Prandtl number\n",

      "k = 0.0265;#Thermal conductivity in W/m-K\n",

      "\n",

      "# Reynold''s number is therefore given as\n",

      "ReL = ((rho*Uinfinity)*L)/mu;\n",

      "\n",

      "#From eq. 4.82, average nusselt number could be given as\n",

      "Nu = (0.036*(Pr**(1/3.0)))*(ReL**0.8);\n",

      "\n",

      "#We can write from the basic math.expression, Nu=hc*L/k, that\n",

      "#Heat transfer coefficient in W/m**2-K\n",

      "hc = (Nu*k)/L;\n",

      "\n",

      "# The surface area that dissipates heat is 0.28 m2\n",

      "print \"Total heat loss from the surface in W is therefore\"\n",

      "#Heat loss from the surface in W\n",

      "q = (hc*0.28)*(Ts-Tinfinity)\n",

      "print round(q)\n"

     ],

     "language": "python",

     "metadata": {},

     "outputs": [

      {

       "output_type": "stream",

       "stream": "stdout",

       "text": [

        "Principles of Heat Transfer, 7th Ed. Frank Kreith et. al Chapter - 4 Example # 4.4 \n",

        "Total heat loss from the surface in W is therefore\n",

        "1896.0\n"

       ]

      }

     ],

     "prompt_number": 10

    }

   ],

   "metadata": {}

  }

 ]

}