removing problem statements

1 files changed, 0 insertions, 59 deletions

diff --git a/Engineering_Heat_Transfer/CHAPTER6.ipynb b/Engineering_Heat_Transfer/CHAPTER6.ipynb
index f8b8ec9f..318545d4 100644
--- a/Engineering_Heat_Transfer/CHAPTER6.ipynb
+++ b/Engineering_Heat_Transfer/CHAPTER6.ipynb
@@ -27,38 +27,29 @@
      "cell_type": "code",

      "collapsed": false,

      "input": [

-      "# Determination of the fluid outlet tetnperature and the tube-wall temperature at the outlet.\n",

       "\n",

-      "#Given\n",

-      "#properties of ethylene glycol at 20 degree celsius from appendix table C5\n",

       "Cp_20=2382\n",

       "rou_20=1.116*1000\n",

       "v_20=19.18e-6\n",

       "kf_20=0.249\n",

       "a_20=0.939e-7\n",

       "Pr_20=204.0\n",

-      "# specifications of 1/2 standard type M seamless copper water tubing from appendix table F2\n",

       "OD=1.588/100.0\n",

       "ID=1.446/100.0\n",

       "A=1.642e-4\n",

       "Q=3.25e-6\n",

       "\n",

-      "#Calculation\n",

       "V=Q/A\n",

-      "# calculation of Reynold's Number to check flow regime\n",

       "Re=V*ID/v_20\n",

-      "# since Re>he 2100, the flow regime is laminar and the hydrodynamic length can be calculated as\n",

       "Z_h=0.05*ID*Re\n",

       "Tbi=20 # bulk-fluid inlet temperature in degree celsius\n",

       "qw=2200 # incident heat flux in W/m**2\n",

       "L=3 # Length of copper tube in m\n",

       "R=ID/2 # inner radius in m\n",

       "Tbo=Tbi+(2*qw*a_20*L)/(V*kf_20*R)\n",

-      "# This result is based on fluid properties evaluated at 20\u00b0C. taken as a first approximation\n",

       "Z_t=0.05*ID*Re*Pr_20\n",

       "Two=Tbo+(11*qw*ID)/(48*kf_20) # The wall temperature at outlet in degree celsius\n",

       "\n",

-      "#Result\n",

       "print\"The bulk-fluid outlet temperature is  degree celsius\",round(Tbo,0),\"C\"\n",

       "print\"The wall temperature at outlet is  degree celsius\",round(Two,0),\"C\"\n"

      ],

@@ -88,18 +79,14 @@
      "cell_type": "code",

      "collapsed": false,

      "input": [

-      "# determination of average convection coefficient\n",

       "\n",

-      "#Given\n",

       "T_avg=(140+70)/2.0\n",

-      "# properties of water at average bulk temperature from appendix table C11\n",

       "rou=0.994*62.4\n",

       "kf=0.363\n",

       "cp=0.9980\n",

       "a=5.86e-3\n",

       "v=0.708e-5\n",

       "Pr=4.34\n",

-      "# specifications of 1 standard type M copper tube from appendix table F2\n",

       "OD=1.125/12.0   # outer diameter in ft\n",

       "ID=0.8792     # inner diameter in ft\n",

       "A=0.006071    # cross sectional area in sq.ft\n",

@@ -112,7 +99,6 @@
       "Tbi=70.0\n",

       "hL=-(rou*V*ID*cp*math.log((Tw-Tbo)/(Tw-Tbi)))/(4*L)\n",

       "\n",

-      "#result\n",

       "print\"The average convective coefficient is \",round(hL/10,1),\"BTU/(hr. sq.ft.degree Rankine\"\n"

      ],

      "language": "python",

@@ -151,15 +137,11 @@
      "cell_type": "code",

      "collapsed": false,

      "input": [

-      "# Determination of the variation of wall temperature with length up to the point where the flow becomes fully developed.\n",

       "\n",

-      "#Given\n",

-      "# properties of milk \n",

       "kf=0.6         # thermal conductivity in W/(m-K)\n",

       "cp=3.85*1000   # specific heat in J/(kg*K)\n",

       "rou=1030      # density in kg/m**3\n",

       "mu=2.12e3     # viscosity in N s/m**2\n",

-      "# specifications of 1/2 standard type K tubing from appendix table F2\n",

       "OD=1.588/100   # outer diameter in m\n",

       "ID=1.340/100   # inner diameter in m\n",

       "A=1.410e-4     # cross sectional area in m**2\n",

@@ -167,10 +149,7 @@
       "V=0.1\n",

       "mu=2.12e-3\n",

       "\n",

-      "#Calculation\n",

-      "# determination of flow regime\n",

       "Re=rou*V*ID/(mu)\n",

-      "# The flow being laminar, the hydrodynamic entry length is calculated as follows\n",

       "ze=0.05*ID*Re\n",

       "Tbo=71.7 # final temperature in degree celsius\n",

       "Tbi=20 # initial temperature in degree celsius\n",

@@ -180,11 +159,9 @@
       "Pr=(cp*mu)/kf # Prandtl Number\n",

       "zf=0.05*ID*Re*Pr\n",

       "\n",

-      "#result\n",

       "print\"The heat flux is \",round(qw,0),\"W/sq.m\"\n",

       "print\"The power required is \",round(q,0),\"W\"\n",

       "print\"The length required for flow to be thermally developed is\",round(zf,1),\"m\"\n",

-      "#plot\n",

       "import matplotlib.pyplot as plt\n",

       "fig = plt.figure()\n",

       "ax = fig.add_subplot(111)\n",

@@ -257,56 +234,40 @@
      "cell_type": "code",

      "collapsed": false,

      "input": [

-      "#Graph the variation between fluid and wall bulb tempratures.\n",

-      "#and how long it will take for the water volume to solidify.\n",

       "\n",

-      "#Given\n",

-      "# The average bulk temperature of the Freon-12 is [-4O +(-4)]/2 = -22\u00b0F\n",

-      "# properties of Freon-12 at average bulk temperature\n",

       "kf=0.04       # thermal conductivity in BTU/(hr.ft.\u00b0R) \n",

       "cp=0.2139     # specific heat in BTU/(lbm-\u00b0R)\n",

       "rou= 1.489*(62.4) # density in lbm/cu.ft\n",

       "v=0.272e-5    #   viscosity in sq.ft/s\n",

       "a=2.04e-3     # diffusivity in sq.ft/hr\n",

       "Pr=4.8        # Prandtl Number\n",

-      "# specifications of 3/8 standard type K copper tubing from appendix table F2\n",

       "OD=0.5/12.0     # outer diameter in ft\n",

       "ID=0.03350      # inner diameter in ft\n",

       "A=0.0008814     # cross sectional area in sq.ft\n",

-      "# Laminar conditions are asssumed\n",

       "z=5.0\n",

       "Tw=32.0\n",

       "Tbo=-4.0\n",

       "Tbi=-40.0\n",

       "L=5.0\n",

       "\n",

-      "#Calculation\n",

       "x=2*a*L/((kf*ID/2.0)*(math.log((Tw-Tbo)/(Tw-Tbi))))   #x=V/hl\n",

-      "#1/Gz=9.09/V\n",

-      "#from the table unless convergence is achieved\n",

       "V=336.0              #ft/h\n",

       "V_final=V/3600.0     #ft/s\n",

       "hl_=V_final/(x)     #\n",

       "\n",

-      "# checking the laminar-flow assumption by calculating the Reynolds number\n",

       "Re=(V_final/3600.0)*ID/v\n",

-      "# The flow is laminar\n",

       "m_Fr=rou*A*V_final\n",

       "As=math.pi*ID*L\n",

       "q=hl_*As*((Tw-Tbo)-(Tw-Tbi))/(log((Tw-Tbo)/(Tw-Tbi)))\n",

       "q_check=m_Fr*cp*(Tbo-Tbi)\n",

       "rou_water=1.002*62.4 # density of water in lbm/ft**3 from appendix table C11\n",

       "m_water=rou_water*L*(2/12.0)*(3/12.0)\n",

-      "# to remove 144 BTU/lbm of water, the time required is caalculated as below\n",

       "t=144*m_water/(-q*3600)\n",

       "\n",

-      "#result\n",

       "print\"The mass flow rate of Freon-12 is \",round(m_Fr*3600,2),\"lbm/hr\"\n",

       "print\"The required time is \",round(t,0),\"hr\"\n",

       "\n",

       "\n",

-      "#plot\n",

-      "#Constant wall temprature with length\n",

       "import matplotlib.pyplot as plt\n",

       "fig = plt.figure()\n",

       "ax = fig.add_subplot(111)\n",

@@ -336,8 +297,6 @@
       "show(a2)\n",

       "show(a3)\n",

       "\n",

-      "#2nd Plot\n",

-      "#Nusslet number with dimensionless length\n",

       "x1=[0.001,0.01,0.1,1]\n",

       "Nu1=[31,11,5.5,5.2]\n",

       "Nu2=[25,10,5.3,5.1]\n",

@@ -412,18 +371,12 @@
      "cell_type": "code",

      "collapsed": false,

      "input": [

-      "# Determination for the power required for heating and the wall temperature at the outlet. \n",

       "\n",

-      "#Given\n",

-      "# The liquid properties are evaluated at the mean temperature of (80 + 20)/2 = 50\u00b0C.\n",

-      "# specifications of 1 standard type K copper water tubing from appendix table F2\n",

       "OD = 2.858/100.0     # outer diameter in m \n",

       "ID = 2.528/100.0     # inner diameter in m \n",

       "A = 5.019e-4         # cross sectional area in sq.m\n",

-      "# 1 oz = 2.957e-5 m**3\n",

       "Q=80*2.957e-5/120   # The volume flow rate of water (at 20\u00b0C) in cu.m/s\n",

       "p_20= 1.000*1000    # density of water at 20\u00b0C in kg/cu.m\n",

-      "# properties of water at 50\u00b0C from appendix table C11\n",

       "p_50= 0.990*(1000)  # density in kg/m3 \n",

       "cp= 4181             # specific heat in J/(kg*K) \n",

       "v = 0.586e-6         # viscosity in sq.m/s \n",

@@ -431,7 +384,6 @@
       "a = 1.533e-7         # diffusivity in sq.m/s \n",

       "Pr = 3.68              # Prandtl number\n",

       "\n",

-      "#CALCULATION\n",

       "import math\n",

       "mass_flow=p_20*Q    # mass flow rate through the tube in kg/s\n",

       "L=3               #  length of tube in m\n",

@@ -444,7 +396,6 @@
       "print\"The power required is\",round(q,0),\"W\"\n",

       "V=mass_flow/(p_50*A) # average velocity at 50 \u00b0C\n",

       "Re=(V*ID)/v        # Reynold's Number\n",

-      "# The flow is laminar so we can use  Figure 6.12 to obtain the information needed on Nusselt number and to find hz\n",

       "inv_Gz=L/(Re*ID*Pr) # The inverse Graetz number at tube end, based on 50\u00b0C conditions\n",

       "Nu=6.9 #value of corresponding Nusselts Number from figure 6.12\n",

       "hz=(Nu*kf)/ID\n",

@@ -478,12 +429,7 @@
      "cell_type": "code",

      "collapsed": false,

      "input": [

-      "#Determine heat gained by the duct and wall temprature\n",

       "\n",

-      "#Given\n",

-      "# determibation of heat gained\n",

-      "# air properties to be calculated at T=(72+45)/2=58.5 degree Fahrenheit\n",

-      "# properties at T=58.5 degree fahrenheit from appendix table D1\n",

       "p = 0.077             # density in lbm/ft^3 \n",

       "cp = 0.240             # specific heat in BTU/(lbm.degree Rankine) \n",

       "v = 15.28e-5          # viscosity in ft^2/s \n",

@@ -495,16 +441,12 @@
       "Tbo=72                # outlet temperature in degree Fahrenheit\n",

       "Tbi=45                # inlet temperature in degree Fahrenheit\n",

       "A=math.pi*(D**2)/4    # cross sectional area of duct in ft^2\n",

-      "# density at outlet temperature in lbm/ft^3 \n",

       "rou_o=.0748\n",

       "V=10                 # average velocity in ft/s\n",

       "mass_flow=rou_o*A*V\n",

       "\n",

-      "#Calculation\n",

-      "# average velocity evaluated by using the average bulk temperature\n",

       "V_avg=mass_flow/(p*A)\n",

       "Re=(V_avg*D)/v\n",

-      "# the flow is in turbulent regime\n",

       "q=mass_flow*cp*(Tbo-Tbi)\n",

       "hc=1                 # convection coefficient between the outside duct wall \n",

       "T_inf=105            # The temperature of attic air surrounding the duct in degree Fahrenheit\n",

@@ -512,7 +454,6 @@
       "qw=(T_inf-Tbo)/((1/hc)+(1/hz)) \n",

       "Two=qw*(1/hz)+Tbo    # The wall temperature at exit in degree Fahrenheit\n",

       "\n",

-      "#result\n",

       "print\"The heat gained by air is\",round(q,3),\"BTU\"\n",

       "print\"The wall temperature at exit is \",round(Two,1),\"F\"\n"

      ],