{ "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "# Chapter14 - Turbulent Flow in Pipe" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 14.1 page no 148" ] }, { "cell_type": "code", "execution_count": 21, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Example 14.1 page no 148\n", "\n", "\n", "\n", " Reynolds no R_e = 9769.23 \n" ] } ], "source": [ "print \"Example 14.1 page no 148\\n\\n\" # a liquid flow through a tube\n", "meu=0.78e-2#viscosity of liquid,g/cm*s\n", "rho=1.50#density,g/cm**3\n", "D=2.54#diameter,cm\n", "v=20#flow velocity\n", "R_e=D*v*rho/meu#reynolds no\n", "print \"\\n Reynolds no R_e = %.2f \"%(R_e)#" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 14.2 page no 148" ] }, { "cell_type": "code", "execution_count": 22, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Example 14.2 page no 148\n", "\n", "\n", "\n", " velocity v = 0.28 ft/s\n" ] } ], "source": [ "from __future__ import division\n", "print \"Example 14.2 page no 148\\n\\n\" # a fluid is moving through a cylinder in laminar flow\n", "meu=6.9216e-4#viscosity of fluid,lb/ft*s\n", "rho=62.4#density,lb/ft**3\n", "D=1/12#diameter,ft\n", "R_e=2100#reynolds no\n", "v=R_e*meu/(D*rho)#minimum velocity at which turbulance will appear\n", "print \"\\n velocity v = %.2f ft/s\"%(v)#" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 14.3 page no 152" ] }, { "cell_type": "code", "execution_count": 23, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Example 14.3 page no 152\n", "\n", "\n", "\n", " fanning friction factor f_a=0.01 \n", "\n", " friction factor f_b1=0.01 \n", "\n", " friction factor f_b2=0.01 \n", "\n", " friction factor f_c=0.01 \n", "\n", " friction factor f_d=0.01 \n", "\n", " friction factor f_e=0.01\n", "\n", " average friction f_av=0.01 \n" ] } ], "source": [ "from math import log10\n", "print \"Example 14.3 page no 152\\n\\n\" # calculate the friction factor by using different equation's\n", "R_e=14080#reynolds no\n", "K_r=0.004#relative roughness (a) by PAT proposed equation\n", "f_a=0.0015+(8*(R_e)**0.30)**-1\n", "print \"\\n fanning friction factor f_a=%0.2f \"%(f_a)# equation for 500050000\n", "f_b1=0.0786/(R_e)**0.25 \n", "print \"\\n friction factor f_b1=%0.2f \"%(f_b1)# equation for 300001000000\n", "f_b2=0.046/(R_e)**0.20\n", "print \"\\n friction factor f_b2=%0.2f \"%(f_b2)# equation for the completely turbulent region \n", "f_c=1/(4*(1.14-2*log10(K_r))**2)\n", "print \"\\n friction factor f_c=%0.2f \"%(f_c)# equation given by jain \n", "f_d=1/(2.28-4*log10(K_r+21.25/(R_e**.9)))**2\n", "print \"\\n friction factor f_d=%0.2f \"%(f_d)#\n", "f_e=0.0085 #from figur 14.2\n", "print \"\\n friction factor f_e=%0.2f\"%(f_e)#\n", "f_av=(f_a+f_b1+f_b2+f_c+f_d+f_e)/6\n", "print \"\\n average friction f_av=%0.2f \"%(f_av)#" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 14.4 page no 154" ] }, { "cell_type": "code", "execution_count": 24, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Example 14.4 page no 154\n", "\n", "\n", "\n", " equivalent diameter D_eq_a=3.33 in\n", "\n", " equivalent diameter D_eq_b=18.00 cm\n", "\n", " equivalent diameter D_eq_c=10.00 cm\n" ] } ], "source": [ "from math import pi\n", "print \"Example 14.4 page no 154\\n\\n\" # for turbulent fluid flow in across section (a) for a rectangle \n", "w=2#width of a rectangle,in\n", "h=10#height of rectangle,in\n", "S_a=h*w#cross sectional area\n", "P_a=2*h+2*w#perimeter of rectangle\n", "D_eq_a=4*S_a/P_a#equivalent diameter\n", "print \"\\n equivalent diameter D_eq_a=%0.2f in\"%(D_eq_a)# (b) for an annulus \n", "d_o=10#outer diameter of annulus\n", "d_i=8#inner diameter \n", "S_b=pi*(d_o**2-d_i**2)/4#cross sectional area\n", "P_b=pi*(d_o-d_i)#perimeter\n", "D_eq_b=(4*S_b)/(P_b)#eq. diameter\n", "print \"\\n equivalent diameter D_eq_b=%0.2f cm\"%(D_eq_b)# (c) for an half- full circle\n", "d_c=10#diameter of circle \n", "S_c=pi*d_c**2/8# cross sectional area\n", "P_c=pi*d_c/2#perimeter\n", "D_eq_c=4*S_c/P_c#eq. diameter\n", "print \"\\n equivalent diameter D_eq_c=%0.2f cm\"%(D_eq_c)# " ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Exampkle 14.5 page no 157" ] }, { "cell_type": "code", "execution_count": 25, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Example 14.5 page no 157\n", "\n", "\n", "\n", " pipe diameter D=0.29 ft\n", "\n", "D=0.69 \n", "\n", " flow velocity v=22.28 ft/s\n" ] } ], "source": [ "print \"Example 14.5 page no 157\\n\\n\" # air is transported through a circular conduit \n", "MW=28.9#molecular weight of air \n", "R=10.73#gas constant\n", "T=500#temperature\n", "P=14.75#pressure,psia applying ideal gas law for density\n", "rho=P*MW/(R*T)#density \n", "rho=0.08#after round off\n", "meu=3.54e-7#viscosity of air at 40 degF assume flow is laminar\n", "q=8.33#flow rate ,ft**3/s\n", "L=800#length of pipe,ft\n", "P_1=.1#pressure at starting point\n", "P_2=.01#pressure at delivery point \n", "D=((128*meu*L*q)/(pi*(P_1-P_2)*144))**(1/4)#diameter\n", "print \"\\n pipe diameter D=%0.2f ft\"%(D)# check the flow type\n", "meu=1.14e-5\n", "R_e1=4*q*rho/(pi*D*meu)#reynolds no print \"\\n reynolds no R_e=%0.2f \"%(R_e)# from R_e we can conclude that laminar flow is not valid\n", "P_drop=12.96#pressure drop P_1-P2 in psf\n", "f=0.005#fanning friction factor\n", "g_c=32.174\n", "D=(32*rho*f*L*q**2/(g_c*pi**2*P_drop))**(0.2)#diamter from new assumption strat the second iteration with the newly calculated D\n", "k=0.00006/12#roughness factor\n", "K_r=k/D#relative roughness \n", "C_f=1.321224\n", "R_e_n=4*q*rho/(pi*D*meu)#new reynolds no print \"\\n new reynolds no R_e=%0.2f \"%(R_e)#\n", "f_n=0.0045#new fanning friction factor\n", "D=(((8*rho*f_n*L*q**2)/(g_c*pi**2*P_drop))**(0.2))*C_f#final calculated diameter because last diameter is same with this\n", "print \"\\nD=%0.2f \"%(D)# iteration may now be terminated\n", "S=pi*(D**2)/4#cross sectional area of pipe\n", "v=q/S#flow velocity\n", "print \"\\n flow velocity v=%0.2f ft/s\"%(v)##printing mistake in book in the value of meu in the formula of D is first time that's why this deviation in answer" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Example 14.6 page no 159" ] }, { "cell_type": "code", "execution_count": 26, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Example 14.6 page no. 159\n", "\n", "\n", "\n", " R_e=106208.60 \n", "\n", " since R_e is more than 4000 flow is turbulent\n" ] } ], "source": [ "print \"Example 14.6 page no. 159\\n\\n\" # ethyl alcohol is pumped through a horizontal tube\n", "rho=789#density .kg/m**3\n", "meu=1.1e-3#viscosity ,kg/m-s\n", "k=1.5e-6#roughness,m\n", "L=60#length of tube,m\n", "q=2.778e-3#flow rate \n", "g=9.807\n", "h_f=30#friction loss\n", "A=(L*q**2)/(g*h_f)\n", "A=1.574e-7\n", "D=0.66*(((k**1.25)*(A**4.75)+meu*(A**5.2)/(q*rho))**.04)\n", "D=0.0377 # calculate velocity of alcohol in the tube\n", "S=3.14*(D)**2/4#surface area\n", "v=q/S#velocity\n", "v=3.93#velocity\n", "neu=1.395e-6#dynamic viscosity\n", "R_e=D*v/neu#reynolds no \n", "print \"\\n R_e=%0.2f \"%(R_e)##printing mistake in book\n", "print \"\\n since R_e is more than 4000 flow is turbulent\" #" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## Exanmple 14.7 page no 160" ] }, { "cell_type": "code", "execution_count": 27, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Example 14.7 page no 160\n", "\n", "\n", "\n", " average velocity v=2.37 m/s\n", "\n", " S=0.00 \n", "\n", " flow rate q=1244.02 m**3/s\n", "\n", " mass flow rate m_dot=1020094.94 kg/s\n", "\n", " v_max=2.91 m/s\n", "\n", " length L_c=1.36 m\n" ] } ], "source": [ "print \"Example 14.7 page no 160\\n\\n\" # kerosene flow ina lng ,smooth ,horizontal pipe\n", "rho=820#density,kg/m**3\n", "D=0.0493#iside diameter of pipe by appendix A.5,m\n", "R_e=60000\n", "meu=0.0016#viscosity,kg/m.s\n", "v=(R_e*meu)/(D*rho)# flow average velocity\n", "print \"\\n average velocity v=%0.2f m/s\"%(v)#\n", "S=(pi/4)*D**2#cross sectional area\n", "print \"\\n S=%0.2f \"%(S)#\n", "q=v/S#flow rate \n", "print \"\\n flow rate q=%0.2f m**3/s\"%(q)##printing mistake in book\n", "m_dot=rho*q#mass flow rate\n", "print \"\\n mass flow rate m_dot=%0.2f kg/s\"%(m_dot)##printing mistake in book in the value of v\n", "n=7#seventh power apply\n", "v_max=v/(2*n**2/((n+1)*(2*n+1)))#maximum velocity\n", "print \"\\n v_max=%0.2f m/s\"%(v_max)# check the assumptioon of fully developed flow\n", "R_e=60000#reynolds no\n", "L_c=4.4*R_e**(1/6)*D#critical length\n", "print \"\\n length L_c=%0.2f m\"%(L_c)# since L_c