{ "cells": [ { "cell_type": "markdown", "metadata": {}, "source": [ "# Ch:17 Sliding contact bearings" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## exa 17-1 - Page 482" ] }, { "cell_type": "code", "execution_count": 1, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ " Tav is 47.29 degC \n", "\n", " delT is 7.3 degC \n" ] } ], "source": [ "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)#" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## exa 17-2 - Page 482" ] }, { "cell_type": "code", "execution_count": 2, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "u is 6.293 cP \n" ] } ], "source": [ "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)#" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## exa 17-3 - Page 483" ] }, { "cell_type": "code", "execution_count": 3, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ " u is 3.469 cP \n", "\n", " Q is 0.2874 lpm \n" ] } ], "source": [ "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)#" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## exa 17-4 - Page 483" ] }, { "cell_type": "code", "execution_count": 4, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "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" ] } ], "source": [ "from numpy import mat,pi,sqrt\n", "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", "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)#" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## exa 17-5 - Page 484" ] }, { "cell_type": "code", "execution_count": 5, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "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" ] } ], "source": [ "from math import sqrt, pi\n", "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." ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## exa 17-6 - Page 485" ] }, { "cell_type": "code", "execution_count": 6, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ " pi is 3.946 MPa \n", "\n", " Q is 25.52 lpm \n" ] } ], "source": [ "from math import log,pi\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." ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "## exa 17-7 - Page 486" ] }, { "cell_type": "code", "execution_count": 7, "metadata": { "collapsed": false }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "pi is 4.44 MPa \n", "\n", "Q is 19.629 lpm \n" ] } ], "source": [ "from math import log, pi\n", "#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)#" ] } ], "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": "2.7.9" } }, "nbformat": 4, "nbformat_minor": 0 }