{ "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "# Chapter 3 Steady State Conduction Multiple Dimension" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Exa 3.1" ] }, { "cell_type": "code", "execution_count": 1, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Heat lost by the pipe is 859.9 W\n" ] } ], "source": [ "#Example Number 3.1\n", "# Calculate the heat loss by the pipe\n", "\n", "# Variable declaration\n", "\n", "d = 0.15 \t\t\t# [m] diameter of pipe\n", "r = d/2 \t\t\t# [m] radius of pipe\n", "L = 4 \t\t\t\t# [m] length of pipe\n", "Tp = 75\t\t\t\t# [degree celsius] pipe wall temperature\n", "Tes = 5 \t\t\t# [degree celsius] earth surface temperature\n", "k = 0.8\t\t\t\t# [W/m per deg C] thermal conductivity of earth \n", "D = 0.20 \t\t\t# [m] depth of pipe inside earth\n", "\n", "\t# We may calculate the shape factor for this situation using equation given in \ttable 3-1 \n", "\t\n", "\t# since D<3*r\n", "#Calculation\n", "import math\n", "S = (2*math.pi*L)/math.acosh(D/r) \t# [m] shape factor\n", "\t# the heat flow is calculated from \n", "q = k*S*(Tp-Tes) \t\t\t# [W]\n", "\n", "#Result\n", "print\"Heat lost by the pipe is\",round(q,1),\"W\"" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Exa 3.2" ] }, { "cell_type": "code", "execution_count": 2, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Heat lost through the walls is: 8.592 kW\n" ] } ], "source": [ "#Example Number 3.2 \n", "# Calculate heat loss through the walls\n", "\n", "# VARIABLE DECLARATION\n", "\n", "a = 0.5 \t # [m] length of side of cubical furnace\n", "Ti = 500 \t # [degree celsius] inside furnace temperature\n", "To = 50 \t # [degree celsius] outside temperature\n", "k = 1.04 \t # [W/m per degree celsius] thermal conductivity of fireclay brick \n", "t = 0.10 \t # [m] wall thickness\n", "A = a*a \t # [square meter] area of one face \n", "\t\t # we compute the total shape factor by adding the shape factors \t\t \t for the walls, edges and corners\n", "\n", "#Calculation\n", "Sw = A/t\t # [m] shape factor for wall\n", "Se = 0.54*a \t # [m] shape factor for edges\n", "Sc = 0.15*t\t # [m] shape factor for corners\n", "\n", "\t\t # there are six wall sections, twelve edges and eight corners, so \t\t\tthe total shape factor S is\n", "\n", "S = 6*Sw+12*Se+8*Sc \t# [m]\n", "\t\t \n", "\t\t# the heat flow is calculated as \n", "\n", "q = k*S*(Ti-To) \t# [W]\n", "\n", "#Result\n", "print\"Heat lost through the walls is:\",round(q/1000,3),\"kW\" \n" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Exa 3.3" ] }, { "cell_type": "code", "execution_count": 4, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Heat lost by disk is: 198.46 W\n" ] } ], "source": [ "#Example Number 3.3\n", "# Calculate the heat loss by the disk\n", "\n", "# Variable declaration\n", "\n", "import math\n", "d = 0.30 \t# [m] diameter of disk\n", "r = d/2 \t# [m] radius of disk\n", "Td = 95 \t# [degree celsius] disk temperature\n", "Ts = 20 \t# [degree celsius] isothermal surface temperature\n", "k = 2.1 \t# [W/m per degree celsius] thermal conductivity of medium \n", "D = 1.0 \t# [m] depth of disk in a semi-infinite medium\n", "\t# We have to calculate shape factor using relation given in table (3-1) \n", "\t# We select the relation for the shape factor is for the case D/(2*r)>1\n", "\n", "#Calculation\n", "S = (4*math.pi*r)/((math.pi/2)-math.atan(r/(2*D)))\t # [m] shape factor\n", "\t# heat lost by the disk is \n", "q = k*S*(Td-Ts) \t\t\t\t\t # [W]\n", "\n", "#Result\n", "print\"Heat lost by disk is:\",round(q,2),\"W\"" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Exa 3.4" ] }, { "cell_type": "code", "execution_count": 5, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Heat transfer between the disks is: 308.4 W\n" ] } ], "source": [ "#Example Number 3.4 \n", "#Calculate the heat transfer betwwen the disks\n", "\n", "# Variable declaration\n", "\n", "d = 0.50\t # [m] diameter of both disk\n", "r = d/2 \t # [m] radius of disk\n", "Td1 = 80\t # [degree celsius] first disk temperature\n", "Td2 = 20 \t # [degree celsius] second disk temperature\n", "k = 2.3 \t # [W/m per degree celsius] thermal conductivity of medium \n", "D = 1.5\t\t # [m] seperation of disk in a infinite medium\n", "\t# We have to calculate shape factor using relation given in table (3-1) \n", "\t# We select the relation for the shape factor is for the case D>5*r\n", "#Calculation\n", "import math\n", "\n", "S = (4*math.pi*r)/((math.pi/2)-math.atan(r/D)) # [m] shape factor\n", "q = k*S*(Td1-Td2) # [W]\n", "\n", "#Result\n", "print\"Heat transfer between the disks is:\",round(q,1),\"W\" \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": "2.7.6" } }, "nbformat": 4, "nbformat_minor": 0 }