{ "metadata": { "name": "" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "code", "collapsed": false, "input": [ "Chapter 12 : Pneumatic Conveying\n" ], "language": "python", "metadata": {}, "outputs": [] }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ "example 12.1 page no : 240" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# find actual linear flow rate through duct\n", "\n", "import math \n", "from numpy import *\n", "\n", "# Initialization of Variable\n", "rho = 1.22\n", "pi = 3.1428\n", "rhos = 518.\n", "rhoav = 321.\n", "mu = 1.73/10**5\n", "g = 9.81\n", "d = 0.65/1000\n", "d2 = 25.5/100 #dia of duct\n", "ms = 22.7/60 #mass flow rate\n", "\n", "#calculation\n", "e = (rhos-rhoav)/(rhos-rho)\n", "#coeff of quadratic eqn in U\n", "#a*x**2+b*x+c = 0\n", "c = -(1-e)*(rhos-rho)*g\n", "b = 150.*(1-e)**2*mu/d**2/e**3\n", "a = 1.75*(1.-e)*rho/d/e**3\n", "y = poly1d([a,b,c],False)\n", "U = roots(y)\n", "Us = ms*4/pi/d2**2/rhos #superficial speed\n", "Ua = e/e*(U[1]/e+Us/(1-e))\n", "print \"the actual linear flow rate through duct in (m/s): %.4f\"%Ua\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "the actual linear flow rate through duct in (m/s): 0.2059\n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ "example 12.2 page no : 243" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# find maximum carrying capacity of polythene particles\n", "\n", "import math \n", "\n", "# Initialization of Variable\n", "rho = 1.22 #density of air\n", "pi = 3.1428\n", "rhos = 910. #density of polyethene\n", "d = 3.4/1000. #dia of particles\n", "mu = 1.73/10**5.\n", "g = 9.81\n", "dt = 3.54/100. #dia of duct\n", "\n", "#calculation\n", "a = 2.*d**3*rho*g*(rhos-rho)/3/mu**2\n", "print \"R/rho/U**2*(Re**2) = %.4f\"%a\n", "\n", "#using Chart\n", "Re = 2.*10**3\n", "U = mu*Re/d/rho\n", "b = U/(g*dt)**.5\n", "if b>0.35:\n", " print \"choking can occur of this pipe system\"\n", "else:\n", " print \"choking can not occur of this pipe system\"\n", "\n", "#part 2\n", "Uc = 15. #actual gas velocity\n", "e = ((Uc-U)**2/2./g/dt/100.+1)**(1./-4.7)\n", "Usc = (Uc-U)*(1-e) #superficial speed of solid\n", "Cmax = Usc*rhos*pi*dt**2./4\n", "print \"the maximum carrying capacity of polythene particles in (kg/s) %.4f\"%Cmax\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "R/rho/U**2*(Re**2) = 952227.8618\n", "choking can occur of this pipe system\n", "the maximum carrying capacity of polythene particles in (kg/s) 0.5949\n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ "example 12.3 page no : 245" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# find Pressure value in kN/m**2\n", "\n", "import math \n", "\n", "# Initialization of Variable\n", "rho = 1.22 #density of air\n", "pi = 3.1428\n", "rhos = 1400. #density of coal\n", "mu = 1.73/10**5.\n", "g = 9.81\n", "U = 25.\n", "Ut = 2.80\n", "l = 50.\n", "ms = 1.2 #mass flow rate\n", "mg = ms/10. #mass flow of gas\n", "\n", "#calculation\n", "Qs = ms/rhos #flow of solid\n", "Qg = mg/rho #flow of gas\n", "us = U-Ut #actual linear velocity\n", "A = Qg/U\n", "Us = Qs/A #solid velocity\n", "e = (us-Us)/us\n", "d = math.sqrt(4*A/pi)\n", "def fround(x,n):\n", " # fround(x,n)\n", " # Round the floating point numbers x to n decimal places\n", " # x may be a vector or matrix# n is the integer number of places to round to\n", " y = round(x*10**n)/10.**n\n", " return y\n", "\n", "d = fround(d,4)\n", "Re = d*rho*U/mu\n", "\n", "#using moody's chart\n", "phi = 2.1/1000 #friction factor\n", "P1 = 2*phi*U**2*l*rho/d*2\n", "f = 0.05/us\n", "P2 = 2*l*f*(0.0098)*rhos*us**2/d\n", "P2 = fround(P2/1000,1)*1000\n", "delP = rho*e*U**2+rhos*(0.0098)*us**2+P1+P2\n", "#print (delP,\"the pressure difference in kN/m**2 \")\n", "print 'The Pressure value in kN/m**2 is %.1f'%(delP/1000)\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The Pressure value in kN/m**2 is 33.5\n" ] } ], "prompt_number": 4 }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ "example 12.4 page no : 250" ] }, { "cell_type": "code", "collapsed": false, "input": [ "# find The Pressure value in kN/m**2\n", "\n", "import math \n", "\n", "# Initialization of Variable\n", "rho = 1.22 #density of air\n", "pi = 3.1428\n", "rhos = 1090. #density of steel\n", "mu = 1.73/10.**5\n", "g = 9.81\n", "d = 14.5/100.\n", "Qg = 0.4\n", "Qs = 5000./3600./1090.\n", "Ut = 6.5\n", "ar = 0.046/1000 #absolute roughness\n", "l = 18.5 #length\n", "\n", "#calculation\n", "def fround(x,n):\n", " # fround(x,n)\n", " # Round the floating point numbers x to n decimal places\n", " # x may be a vector or matrix# n is the integer number of places to round to\n", " y = round(x*10**n)/10**n\n", " return y\n", "\n", "Us = Qs/pi/d**2*4 #solid velocity\n", "U = Qg/pi/d**2*4\n", "us = U-Ut #actual linear velocity\n", "e = 1-Us/us\n", "e = fround(e,4)\n", "Re = rho*U*d/mu\n", "rr = ar/d #relative roughness\n", "\n", "#using moody's diagram\n", "phi = 2.08/1000\n", "P1 = 2*phi*U**2*l*rho/d*2\n", "f = 0.05/us\n", "P2 = 2*l*f*(1-e)*rhos*us**2/d\n", "P2 = fround(P2/1000,2)*1000\n", "delP = rhos*(1-e)*us**2+rhos*(1-e)*g*l+P1+P2\n", "#print (delP,\"the pressure difference in kN/m**2 \")\n", "print 'The Pressure value in kN/m**2 is %.2f'%(delP/1000)\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The Pressure value in kN/m**2 is 4.21\n" ] } ], "prompt_number": 6 }, { "cell_type": "heading", "level": 3, "metadata": {}, "source": [ "example 12.5 pageno :254" ] }, { "cell_type": "code", "collapsed": false, "input": [ "'''\n", "find\n", "The maximum pressure drop\n", "The minimum pressure drop\n", "'''\n", "\n", "import math \n", "\n", "# Initialization of Variable\n", "l = 25.\n", "pi = 3.1428\n", "rhos = 2690. #density of ore\n", "emin = 0.6\n", "emax = 0.8\n", "g = 9.81\n", "\n", "#calculation\n", "Pmax = rhos*(1-emin)*g*l\n", "print \"The maximum pressure drop in (N/m**2):\",Pmax\n", "Pmin = rhos*(1-emax)*g*l\n", "print \"The minimum pressure drop in (N/m**2):\",Pmin\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The maximum pressure drop in (N/m**2): 263889.0\n", "The minimum pressure drop in (N/m**2): 131944.5\n" ] } ], "prompt_number": 7 }, { "cell_type": "code", "collapsed": false, "input": [], "language": "python", "metadata": {}, "outputs": [] } ], "metadata": {} } ] }