{
 "metadata": {
  "name": "",
  "signature": "sha256:d8d637e7ecf72daf7222d9457fa6d30ac8f9c6b3089d299c87aaa45e1504178c"
 },
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 "worksheets": [
  {
   "cells": [
    {
     "cell_type": "heading",
     "level": 1,
     "metadata": {},
     "source": [
      "Ch:17 Sliding contact bearings"
     ]
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "exa 17-1 - Page 482"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "from __future__ import division\n",
      "from math import pi, sqrt\n",
      "Ta=22#\n",
      "u=7/10**9#\n",
      "nj=20#\n",
      "r=25#\n",
      "l=2*r#\n",
      "Ao=30000#\n",
      "Uo=15.3/10**3#\n",
      "c=0.025#\n",
      "#specific weight of the material is rho\n",
      "rho=8.46*(10**-6)#\n",
      "Cp=179.8#\n",
      "Tf=Ta+(16*pi**3*u*nj**2*l*r**3/(Uo*Ao*c))#\n",
      "# avg mean film temperature is Tav\n",
      "Tav=(Tf-Ta)/2#\n",
      "x= l*c*rho*pi*r*nj*Cp*10**3#\n",
      "y=Ao*Tav*Uo#\n",
      "delT=y/x#\n",
      "print \" Tav is %0.2f degC \"%(Tav)#\n",
      "print \"\\n delT is %0.1f degC \"%(delT)#"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        " Tav is 47.29 degC \n",
        "\n",
        " delT is 7.3 degC \n"
       ]
      }
     ],
     "prompt_number": 1
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "exa 17-2 - Page 482"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "l=60#\n",
      "d=60#\n",
      "r=d/2#\n",
      "ho=0.008#\n",
      "c=0.04#\n",
      "S=0.0446#\n",
      "nj=1260/60#\n",
      "W=6000#\n",
      "p=W/(l*d)#\n",
      "u=S*(c/r)**2*p/nj#\n",
      "u=u*10**9#\n",
      "print \"u is %0.3f cP \"%(u)#"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "u is 6.293 cP \n"
       ]
      }
     ],
     "prompt_number": 2
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "exa 17-3 - Page 483"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "d=60#\n",
      "r=30#\n",
      "l=60#\n",
      "c=0.8*10**-3*r#\n",
      "ho=0.2*c#\n",
      "W=21000/2#\n",
      "p=W/(l*d)#\n",
      "S=0.0446#\n",
      "nj=1440/60#\n",
      "u=S*(c/r)**2*p/nj#\n",
      "u=u*10**9#\n",
      "# since Q/(r*nj*l)=4.62\n",
      "Q=4.62*r*c*nj*l#\n",
      "Q=Q*60/10**6#\n",
      "print \" u is %0.3f cP \"%(u)#\n",
      "print \"\\n Q is %0.4f lpm \"%(Q)#"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        " u is 3.469 cP \n",
        "\n",
        " Q is 0.2874 lpm \n"
       ]
      }
     ],
     "prompt_number": 3
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "exa 17-4 - Page 483"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "l=60#\n",
      "d=60#\n",
      "r=d/2#\n",
      "W=3000#\n",
      "p=W/(l*d)#\n",
      "u=30*10**-9#\n",
      "c=0.06#\n",
      "nj=1440/60#\n",
      "S=(r/c)**2*u*nj/p#\n",
      "#For ratio l/d=1, values of different parameters are given in matrix A corresponding to S\n",
      "from numpy import mat\n",
      "A=mat([[0,0,0,0,0,0],[0,1, 0.264, 0.6, 5.79, 3.99],[0,1, 0.121, 0.4 ,3.22, 4.33]])#\n",
      "#let ho/c=x\n",
      "x=(A[1,3])-((A[1,3]-(A[2,3]))*((A[1,2])-S)/((A[1,2])-(A[2,2])))#\n",
      "#let y= (r/c)*f=CFV\n",
      "y=(A[1,4])-(A[1,4]-(A[2,4]))*((A[1,2])-S)/((A[1,2])-(A[2,2]))#\n",
      "#let z=Q/(r*c*nj*l)=FV\n",
      "z=(A[1,5])-((A[1,5]-(A[2,5]))*((A[1,2])-S)/((A[1,2])-(A[2,2])))#\n",
      "f=y*c/r#\n",
      "ho=x*c#\n",
      "Q=z*r*c*nj*l#\n",
      "Q=Q*60/10**6#\n",
      "delT=8.3*p*y/z#\n",
      "#let power lost in friction be Pf\n",
      "Pf=2*pi*nj*f*W*r/10**6#\n",
      "print \" f is %0.5f  \"%(f)#\n",
      "print \"\\n ho is %0.3f mm \"%(ho)#\n",
      "print \"\\n Q is %0.3f lpm \"%(Q)#\n",
      "print \"\\n delT is %0.1f degC \"%(delT)#\n",
      "print \"\\n Pf is %0.4f KW \"%(Pf)#"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        " f is 0.00985  \n",
        "\n",
        " ho is 0.032 mm \n",
        "\n",
        " Q is 0.638 lpm \n",
        "\n",
        " delT is 8.3 degC \n",
        "\n",
        " Pf is 0.1337 KW \n"
       ]
      }
     ],
     "prompt_number": 4
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "exa 17-5 - Page 484"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "W=22000#\n",
      "nj=960/60#\n",
      "p=2.4#\n",
      "u=20*10**-9#\n",
      "d=sqrt(W/p)#\n",
      "d=96#\n",
      "r=d/2#\n",
      "l=d#\n",
      "S=0.0446#\n",
      "pact=W/(l*d)#\n",
      "#x=r/c#\n",
      "x=sqrt(S*pact/(u*nj))#\n",
      "c=r/x#\n",
      "ho=0.2*c#\n",
      "Q=r*c*nj*l*4.62#\n",
      "Q=Q*60/10**6#\n",
      "print \" d is %0.0f mm \"%(d)#\n",
      "print \"\\n l is %0.0f mm \"%(l)#\n",
      "print \"\\n ho is %0.4f mm \"%(ho)#\n",
      "print \"\\n Q is %0.3f lpm \"%(Q)#\n",
      "#The difference in answer to Q is due to rounding -off the value of c."
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        " d is 96 mm \n",
        "\n",
        " l is 96 mm \n",
        "\n",
        " ho is 0.0166 mm \n",
        "\n",
        " Q is 1.701 lpm \n"
       ]
      }
     ],
     "prompt_number": 5
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "exa 17-6 - Page 485"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "from math import log\n",
      "W=400*10**3#\n",
      "Ro=200#\n",
      "Ri=160#\n",
      "ho=0.1#\n",
      "t=150#\n",
      "# specific gravity is rho\n",
      "rho=0.86#\n",
      "pi=2*W*log(Ro/Ri)/(pi*(Ro**2-Ri**2))#\n",
      "zk=(0.22*t)-(180/t)#\n",
      "z=rho*zk#\n",
      "u=z/(10**9)#\n",
      "Q=pi*pi*ho**3/(6*u*log(Ro/Ri))#\n",
      "Q=Q*60/10**6#\n",
      "print \" pi is %0.3f MPa \"%(pi)#\n",
      "print \"\\n Q is %0.2f lpm \"%(Q)#\n",
      "  \n",
      "  #The difference in answer to Q is due to rounding -off of values."
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        " pi is 3.946 MPa \n",
        "\n",
        " Q is 25.52 lpm \n"
       ]
      }
     ],
     "prompt_number": 6
    },
    {
     "cell_type": "heading",
     "level": 2,
     "metadata": {},
     "source": [
      "exa 17-7 - Page 486"
     ]
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "#let number of pads be n\n",
      "n=4#\n",
      "W=100*10**3#\n",
      "Ro=125#\n",
      "Ri=50#\n",
      "t=200#\n",
      "ho=0.15#\n",
      "pi=2*W*log(Ro/Ri)/(pi*(Ro**2-Ri**2))#\n",
      "zk=(0.22*t)-(180/t)#\n",
      "# specific gravity is rho\n",
      "rho=0.86#\n",
      "z=rho*zk#\n",
      "u=z/(10**9)#\n",
      "Q=pi*pi*ho**3/(6*u*log(Ro/Ri))#\n",
      "Q=Q*60/10**6#\n",
      "print \"pi is %0.2f MPa \"%(pi)#\n",
      "print \"\\nQ is %0.3f lpm \"%(Q)#"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "output_type": "stream",
       "stream": "stdout",
       "text": [
        "pi is 3.54 MPa \n",
        "\n",
        "Q is 12.441 lpm \n"
       ]
      }
     ],
     "prompt_number": 7
    }
   ],
   "metadata": {}
  }
 ]
}