{ "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "# BASIC CONCEPTS" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "# Example 1.1 Page 16-17" ] }, { "cell_type": "code", "execution_count": 6, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "\n", " \n", " Rate of Heat Transfer per unit area = 0.74 W\n" ] } ], "source": [ "# L=.045; \t\t \t\t\t#[m] - Thickness of conducting wall\n", "delT = 350 - 50; \t\t #[C] - Temperature Difference across the Wall\n", "k=370; \t\t\t\t\t#[W/m.C] - Thermal Conductivity of Wall Material\n", "#calculations\n", "#Using Fourier's Law eq 1.1\n", "q = k*delT/(L*10**6); \t\t\t#[MW/m^2] - Heat Flux\n", "#results\n", "print '%s %.2f %s' %(\"\\n \\n Rate of Heat Transfer per unit area =\",q,\" W\");\n", "#END" ] }, { "cell_type": "markdown", "metadata": { "collapsed": true }, "source": [ "# Example 1.2 Page 17" ] }, { "cell_type": "code", "execution_count": 7, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "\n", " \n", " Rate of Heat Transfer per unit area = 29452.50 W\n", "\n", " \n", " The Temperature Gradient in the flow direction = -700.00 C/m\n" ] } ], "source": [ "L = .15; \t\t \t\t\t#[m] - Thickness of conducting wall\n", "delT = 150 - 45; \t\t #[C] - Temperature Difference across the Wall\n", "A = 4.5; #[m^2] - Wall Area\n", "k=9.35; \t\t\t\t\t#[W/m.C] - Thermal Conductivity of Wall Material\n", "#calculations\n", "#Using Fourier's Law eq 1.1\n", "Q = k*A*delT/L; \t\t\t#[W] - Heat Transfer\n", "#Temperature gradient using Fourier's Law\n", "TG = - Q/(k*A); #[C/m] - Temperature Gradient\n", "#results\n", "print '%s %.2f %s' %(\"\\n \\n Rate of Heat Transfer per unit area =\",Q,\" W\");\n", "print '%s %.2f %s' %(\"\\n \\n The Temperature Gradient in the flow direction =\",TG,\" C/m\");\n", "#END" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "# Example 1.3 Page 17-18" ] }, { "cell_type": "code", "execution_count": 8, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "\n", " \n", " Area of the wall = 0.76 m^2\n" ] } ], "source": [ "x = .0825; \t\t \t\t\t#[m] - Thickness of side wall of the conducting oven\n", "delT = 175 - 75; \t\t #[C] - Temperature Difference across the Wall\n", "k=0.044; \t\t\t\t\t#[W/m.C] - Thermal Conductivity of Wall Insulation\n", "Q = 40.5; #[W] - Energy dissipitated by the electric coil withn the oven \n", "#calculations\n", "#Using Fourier's Law eq 1.1\n", "A = (Q*x)/(k*delT); \t\t#[m^2] - Area of wall\n", "#results\n", "print '%s %.2f %s' %(\"\\n \\n Area of the wall =\",A,\" m^2\");\n", "#END\n" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "# Example 1.4 Page 18-19" ] }, { "cell_type": "code", "execution_count": 9, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "\n", " \n", " Rate of Heat Transfer = 8400.00 W\n" ] } ], "source": [ "delT = 300-20; \t\t #[C] - Temperature Difference across the Wall\n", "h = 20; \t\t\t\t\t#[W/m^2.C] - Convective Heat Transfer Coefficient\n", "A = 1*1.5; #[m^2] - Wall Area\n", "#calculations\n", "#Using Newton's Law of cooling eq 1.6\n", "Q = h*A*delT; \t\t\t#[W] - Heat Transfer\n", "#results\n", "print '%s %.2f %s' %(\"\\n \\n Rate of Heat Transfer =\",Q,\" W\");\n", "#END" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "# Example 1.5 Page 19" ] }, { "cell_type": "code", "execution_count": 10, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Electric Power to be supplied = Convective Heat loss\n", "\n", " \n", " Rate of Heat Transfer = 63.60 W\n" ] } ], "source": [ "L=.15; \t\t \t\t\t#[m] - Length of conducting wire\n", "d = 0.0015; #[m] - Diameter of conducting wire\n", "A = 22*d*L/7; #[m^2] - Surface Area exposed to Convection\n", "delT = 120 - 100; \t\t #[C] - Temperature Difference across the Wire\n", "h = 4500; \t\t\t\t\t#[W/m^2.C] - Convective Heat Transfer Coefficient\n", "print 'Electric Power to be supplied = Convective Heat loss';\n", "#calculations\n", "#Using Newton's Law of cooling eq 1.6\n", "Q = h*A*delT; \t\t\t#[W] - Heat Transfer\n", "Q = round(Q,1);\n", "#results\n", "print '%s %.2f %s' %(\"\\n \\n Rate of Heat Transfer =\",Q,\" W\");\n", "#END" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "# Example 1.6 Page 20-21" ] }, { "cell_type": "code", "execution_count": 11, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "\n", " \n", " Rate of Heat Transfer = 4343.08 W\n", "\n", " The equivalent thermal resistance = 0.06 C/W\n", "\n", " The equivalent convection coefficient = 11.14 W/(m^2 * C)\n" ] } ], "source": [ "T1 = 300 + 273; \t\t #[K] - Temperature of 1st surface\n", "T2 = 40 + 273; #[K] - Temperature of 2nd surface\n", "A = 1.5; #[m^2] - Surface Area\n", "F = 0.52; \t\t\t\t #[dimensionless] - The value of Factor due geometric location and emissivity\n", "sigma = 5.67*(10**-8) #(W/(m^2 * K^4)) - Stephen - Boltzmann Constant\n", "#calculations\n", "#Using Stephen-Boltzmann Law eq 1.9\n", "Q = F*sigma*A*(T1**4 - T2**4) \t #[W] - Heat Transfer\n", "#Equivalent Thermal Resistance using eq 1.10\n", "Rth = (T1-T2)/Q; #[C/W] - Equivalent Thermal Resistance\n", "#Equivalent convectoin coefficient using h*A*(T1-T2) = Q\n", "h = Q/(A*(T1-T2)); #[W/(m^2*C)] - Equivalent Convection Coefficient\n", "#results\n", "print '%s %.2f %s' %(\"\\n \\n Rate of Heat Transfer =\",Q,\" W\");\n", "print '%s %.2f %s' %(\"\\n The equivalent thermal resistance =\",Rth,\" C/W\");\n", "print '%s %.2f %s' %(\"\\n The equivalent convection coefficient =\",h,\" W/(m^2 * C)\");\n", "#END" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "# Example 1.7 Page 21-22" ] }, { "cell_type": "code", "execution_count": 12, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "\n", " \n", " Rate of Heat Transfer = 313.86 C\n" ] } ], "source": [ "L = 0.025; #[m] - Thickness of plate\n", "A = 0.6*0.9; #[m^2] - Area of plate \n", "Ts = 310; \t\t #[C] - Surface Temperature of plate\n", "Tf = 15; #[C] - Temperature of fluid(air)\n", "h = 22; \t\t\t\t\t #[W/m^2.C] - Convective Heat Transfer Coefficient\n", "Qr = 250; \t\t\t\t #[W] - Heat lost from the plate due to radiation\n", "k = 45; \t\t\t\t\t #[W/m.C] - Thermal Conductivity of Plate\n", "#calculations\n", "# In this problem, heat conducted by the plate is removed by a combination of convection and radiation\n", "# Heat conducted through the plate = Convection Heat losses + Radiation Losses\n", "# If Ti is the internal plate temperature, then heat conducted = k*A*(Ts-Ti)/L\n", "Qc = h*A*(Ts-Tf); #[W] - Convection Heat Loss\n", "Ti = Ts + L*(Qc + Qr)/(A*k); \t #[C] - Inside plate Temperature\n", "#results\n", "print '%s %.2f %s' %(\"\\n \\n Rate of Heat Transfer =\",Ti,\" C\");\n", "#END" ] }, { "cell_type": "markdown", "metadata": { "collapsed": false }, "source": [ "# Example 1.8 Page 22" ] }, { "cell_type": "code", "execution_count": 13, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "\n", " \n", " The temperature Gradient = -1352.21 C/m\n" ] } ], "source": [ "Ts = 250; \t\t #[C] - Surface Temperature\n", "Tsurr = 110; #[C] - Temperature of surroundings\n", "h = 75; \t\t\t\t\t #[W/m^2.C] - Convective Heat Transfer Coefficient\n", "F = 1; \t\t\t\t #[dimensionless] - The value of Factor due geometric location and emissivity\n", "sigma = 5.67*(10**-8) #(W/(m^2 * K^4)) - Stephen - Boltzmann Constant\n", "k = 10; \t\t\t\t\t #[W/m.C] - Thermal Conductivity of Solid\n", "#calculations\n", "# Heat conducted through the plate = Convection Heat losses + Radiation Losses\n", "qr = F*sigma*((Ts+273)**4-(Tsurr+273)**4) #[W/m^2] - #[W] - Heat lost per unit area from the plate due to radiation\n", "qc = h*(Ts-Tsurr); #[W/m^2] - Convection Heat Loss per unit area\n", "TG = -(qc+qr)/k; \t #[C/m] - Temperature Gradient\n", "#results\n", "print '%s %.2f %s' %(\"\\n \\n The temperature Gradient =\",TG,\" C/m\");\n", "#END" ] } ], "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": "2.7.10" } }, "nbformat": 4, "nbformat_minor": 0 }