{ "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "# Chapter 22: Transport Processes in Gas" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Ex22.1:pg-911" ] }, { "cell_type": "code", "execution_count": 22, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "\n", " Example 22.1 \n", "\n", "\n", " Mean free path = math.exp m,\n", " The fraction of molecules have free path longer than 2*lambda = 13.5335283237 percent\n" ] } ], "source": [ "# Given that\n", "p = 1.013e5 # Pressure in Pa\n", "t = 300 # Temperature in K\n", "d = 3.5 # Effective diameter of oxygen molecule in Angstrom \n", "r = 2 # Ratio of free path of molecules with the lambda\n", "print \"\\n Example 22.1 \\n\"\n", "sigma = math.pi*(d*(10**-10))**2\n", "n = p/(t*1.38*(10**-23))\n", "R = math.exp(-r)\n", "print \"\\n Mean free path = math.exp m,\\n The fraction of molecules have free path longer than 2*lambda = \",R*100, \" percent\"\n", "# Answer given in the book contain round off error for mean free path." ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Ex22.2:pg-912" ] }, { "cell_type": "code", "execution_count": 23, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "\n", " Example 22.2 \n", "\n", "\n", " Pressure of the gas = 134.236067593 Pa,\n", " No of collisions made by a molecule per meter of path = math.exp 38022.8136882\n" ] } ], "source": [ "\n", "# Given that\n", "lambda1 = (2.63e-5) # Mean free path of the molecules of the gas in m\n", "t = 25 # Temperature in degree centigrade\n", "r = 2.56e-10 # Radius of the molecules in m\n", "print \"\\n Example 22.2 \\n\"\n", "sigma = 4*math.pi*r**2\n", "n = 0.707/(sigma*lambda1)\n", "p = n*(t+273)*(1.38*10**-23)\n", "N = 1.0/lambda1\n", "print \"\\n Pressure of the gas = \",p,\" Pa,\\n No of collisions made by a molecule per meter of path = math.exp\",N\n", "\n" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Ex22.3:pg-912" ] }, { "cell_type": "code", "execution_count": 24, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "\n", " Example 22.3 \n", "\n", "\n", " The no of free paths which are longer than, \n", " 10 cm = 3679.0 ,\n", " 20 cm = 1354.0 ,\n", " 50 cm = 68.0 ,\n", "\n", " The no of free paths which are between,\n", " 5 cm and 10 cm = -2387.0 ,\n", " 9.5 cm and 10.5 cm = -369.0 ,\n", " 9.9 cm and 10.1 cm = -74.0 ,\n", "\n", " The no of free paths which are exactly 10 cm = -0.0\n" ] } ], "source": [ "\n", "# Given that\n", "import math\n", "from scipy import integrate \n", "lambda1 = 10.0 # Mean free path of the gas in cm\n", "N0 = 10000.0 # No of free paths\n", "x1 = 10.0 # In cm\n", "x2 = 20.0 # In cm\n", "x3 = 50.0 # In cm\n", "x4 = 5.0 # In cm\n", "x5 = 9.5 # In cm\n", "x6 = 10.5 # In cm\n", "x7 = 9.9 # In cm\n", "x8 = 10.1 # In cm\n", "print \"\\n Example 22.3 \\n\"\n", "# For x>10 cm\n", "N1 = N0*(math.exp(-1))\n", "# For x>20 cm\n", "N2 = N0*(math.exp(-2))\n", "# For x>50 cm\n", "N3 = N0*(math.exp(-5))\n", "def f(x): \n", " y = (-N0/lambda1)*(math.exp((-x)/lambda1)),\n", " return y\n", "# For 5>x>10 cm\n", "N4,er = integrate.quad( lambda x: (-N0/lambda1)*(math.exp((-x)/lambda1)),x4,x1)\n", "# For 9.5>x>10.5 cm\n", "N5,e = integrate.quad( lambda x: (-N0/lambda1)*(math.exp((-x)/lambda1)),x5,x6)\n", "# For 9.9>x>10.1 cm\n", "N6,eor = integrate.quad( lambda x: (-N0/lambda1)*(math.exp((-x)/lambda1)),x7,x8)\n", "# For x=10 cm\n", "N7,eer = integrate.quad( lambda x: (-N0/lambda1)*(math.exp((-x)/lambda1)),x1,x1)\n", "print \"\\n The no of free paths which are longer than, \\n 10 cm = \",math. ceil(N1) ,\",\\n 20 cm = \",math. ceil(N2) ,\",\\n 50 cm = \",math. ceil(N3) ,\",\\n\\n The no of free paths which are between,\\n 5 cm and 10 cm = \",math.floor(N4) ,\",\\n 9.5 cm and 10.5 cm = \",math.floor(N5) ,\",\\n 9.9 cm and 10.1 cm = \",math.floor(N6) ,\",\\n\\n The no of free paths which are exactly 10 cm = \",N7 \n", "\n" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Ex22.4:pg-913" ] }, { "cell_type": "code", "execution_count": 25, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "\n", " Example 22.4 \n", "\n", "\n", " Coefficient of viscosity = math.exp Ns/m**2 2.051171875e-05\n" ] } ], "source": [ "# Given that\n", "p = 1.0 # Pressure in atm\n", "t = 300.0 # Temperature in K\n", "print \"\\n Example 22.4 \\n\"\n", "# From previous example, we have\n", "m = 5.31e-26 # In kg/molecule\n", "v = 445.0 # In m/s\n", "sigma = 3.84e-19 # In m**2\n", "# Therefore\n", "mu = (1.0/3.0)*(m*v/sigma)\n", "print \"\\n Coefficient of viscosity = math.exp Ns/m**2\",mu" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Ex22.5:pg-913" ] }, { "cell_type": "code", "execution_count": 26, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "\n", " Example 22.5 \n", "\n", "\n", " Thermal conductivity = 0.0 W/mK,\n", " If the gas has Maxwellian velocity distribution,\n", " Thermal conductivity = 5.98958333333e-05 W/mK\n" ] } ], "source": [ "\n", "# Given that\n", "p = 1.0 # Pressure in atm\n", "t = 300.0 # Temperature in K\n", "F = 5.0 # For oxygen gas degree of freedom\n", "print \"\\n Example 22.5 \\n\"\n", "v = 445.0 # In m/s as given in the book\n", "m = 5.31e-26 # Mass of oxygen molecule in kg\n", "sigma = 3.84e-19 # As given in the book in m**2\n", "k = (1/6)*(v*F*(1.38*10**-23))/sigma\n", "# If the gas has Maxwellian velocity distribution,\n", "k_ = (1.0/3.0)*(F*(1.38*10**-23)/sigma)*((1.38*10**-23)*t/(math.pi*m))**(1/2)\n", "print \"\\n Thermal conductivity = \",k ,\" W/mK,\\n If the gas has Maxwellian velocity distribution,\\n Thermal conductivity = \",k_ ,\" W/mK\"\n", "\n" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Ex22.6:pg-914" ] }, { "cell_type": "code", "execution_count": 27, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "\n", " Example 22.6 \n", "\n", "\n", " Pressure in the cathode ray tube = 0.142844028924 Pa\n" ] } ], "source": [ "import math\n", "# Given that\n", "F = .90 # Fraction of electrons leaving the cathode ray reach the anode without making a collision\n", "x = 0.2 # Distance between cathode ray and anode in m\n", "d = 3.6e-10 # Diameter of ion in m\n", "t = 2000.0 # Temperature of electron in K\n", "print \"\\n Example 22.6 \\n\"\n", "lambda1 = x/(math.log(1/F))\n", "sigma = math.pi*(d**2)\n", "n = 4/(sigma*lambda1)\n", "p = n*(1.38*10**-23)*(t)\n", "print \"\\n Pressure in the cathode ray tube = \",p ,\" Pa\"" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Ex22.7:pg-914" ] }, { "cell_type": "code", "execution_count": 28, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "\n", " Example 22.7 \n", "\n", "\n", " No of collisions per sec are made by one molecule with the other molecule = 9962400.07749 \n", "The no of molecules strike the flask per sq. cm = 6.11714975845e+20 \n", " No of molecules in the flask = 2.44685990338e+22\n" ] } ], "source": [ "# Given that\n", "V = 1.0 # Volume of the flask in litre\n", "p = 1.0 # Pressure in atm\n", "t = 300.0 # Temperature in K\n", "r = 1.8e-10 # Radius of oxygen gas molecule in m\n", "m = 5.31e-26 # Mass of oxygen molecule in kg\n", "print \"\\n Example 22.7 \\n\"\n", "n = (p*(1.013e5))/((1.38e-23)*(t)*1000)\n", "sigma = 4*math.pi*(r**2)\n", "v = ((8*(1.38e-23)*t)/(math.pi*m))**(1/2)\n", "z = sigma*n*v*1000\n", "N = (1.0/4.0)*(n*0.1*v)\n", "print \"\\n No of collisions per sec are made by one molecule with the other molecule =\", z,\"\\nThe no of molecules strike the flask per sq. cm =\",N,\"\\n No of molecules in the flask =\",n" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Ex22.8:pg-915" ] }, { "cell_type": "code", "execution_count": 29, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "\n", " Example 22.8 \n", "\n", "\n", " Time = 1.00003111262 s\n" ] } ], "source": [ "# Given that\n", "lambda1 = 2.0 # Mean free path in cm\n", "T = 300.0 # Temperature in K\n", "r = 0.5 # As half of the molecules did not make any collision\n", "print \"\\n Example 22.8 \\n\"\n", "x = lambda1*(math.log(1/r))\n", "v = 445.58 # For oxygen at 300K in m/s\n", "t = x/(v*100)\n", "print \"\\n Time =\", math.exp(t), \"s\"\n", "\n" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Ex22.9:pg-915" ] }, { "cell_type": "code", "execution_count": 30, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "\n", " Example 22.9 \n", "\n", "\n", " Pressure = 1.03636998072 N/m**2\n" ] } ], "source": [ "\n", "# Given that\n", "f = 0.9 # Fraction of electrons leaving the cathode ray and reaching the anode without making any collision\n", "x = 20.0 # Distance between cathode ray tube and anode in cm\n", "sigma = 4.07e-19 # Collision cross section of molecules in m**2\n", "T = 2000 # Temperature in K\n", "print \"\\n Example 22.9 \\n\"\n", "lambda1 = (x*0.01)/(math.log(1.0/f))\n", "n = 1/(sigma*lambda1)\n", "p = n*(1.38e-23)*T\n", "print \"\\n Pressure =\", math.exp(p), \"N/m**2\"\n", "# The answer given in the book contains round off error.\n" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Ex22.10:pg-916" ] }, { "cell_type": "code", "execution_count": 31, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "\n", " Example 22.10 \n", "\n", "\n", " Initial concentration gradient of reactive molecules = 0.0 molecules/m**4, \n", " The no of reactive molecules per sec cross a cross section at the mid point of the tube from left to right = 0.9 molecules/m**2,\n", " The no of reactive molecules per sec cross a cross section at the mid point of the tube from right to left = 4.08598425576e-12 molecule/m**2,\n", " Initial net rate of diffusion = 0.0112863158384 g/m**2-s\n" ] } ], "source": [ "# Given that\n", "l = 2.0 # Length of tube in m\n", "a = 1e-4 # Cross section of the tube in m**2\n", "p = 1.0 # Pressure in atm\n", "t = 0 # Temperature in degree centigrade\n", "r = 0.5 # Fraction of the carbon atoms which are radioactive C14\n", "sigma = 4e-19 # Collision cross section area in m**2\n", "print \"\\n Example 22.10 \\n\"\n", "n = (p*1.01325e+5)/((1.38e-23)*(t+273))\n", "C_g = -n/l\n", "m = (46/6.023)*10**-26 # In kg/molecule\n", "v = (2.55*(1.38e-23)*(t+273)/m)**(1/2.0)\n", "lambda1 = (1.0/(sigma*n))\n", "gama = (1.0/4)*(v*n) - (1/6.0)*(v*lambda1*(C_g))\n", "gama_ = (1/4.0)*(v*n) + (1.0/6.0)*(v*lambda1*(C_g))\n", "x = (1.0/4)*(v*n)\n", "y = (1.0/6)*(v*lambda1*(C_g))\n", "d = (1.0/6)*(v*lambda1*(-1*C_g))*2*(m)\n", "a=x+y\n", "b=x-y\n", "print \"\\n Initial concentration gradient of reactive molecules =\",math.exp (C_g),\" molecules/m**4, \\n The no of reactive molecules per sec cross a cross section at the mid point of the tube from left to right =\",f , \"molecules/m**2,\\n The no of reactive molecules per sec cross a cross section at the mid point of the tube from right to left =\",e ,\" molecule/m**2,\\n Initial net rate of diffusion = \",d*1000 ,\"g/m**2-s\"\n", "# The answer for lambda given in the book conatains calculation error\n", "# The answers contains calculation error\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 }