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-rw-r--r--Engineering_Heat_Transfer/CHAPTER7.ipynb63
1 files changed, 0 insertions, 63 deletions
diff --git a/Engineering_Heat_Transfer/CHAPTER7.ipynb b/Engineering_Heat_Transfer/CHAPTER7.ipynb
index 3c0bf86c..b246db44 100644
--- a/Engineering_Heat_Transfer/CHAPTER7.ipynb
+++ b/Engineering_Heat_Transfer/CHAPTER7.ipynb
@@ -37,18 +37,13 @@
"cell_type": "code",
"collapsed": false,
"input": [
- "# determination of boundary layer growth with length\n",
"\n",
- "#Given\n",
- "# properties of air at 27 degree celsius from appendix table D.1\n",
"rou=1.177 # density in kg/cu.m\n",
"v=15.68e-6 # viscosity in sq.m/s\n",
"L=0.5 # length in m\n",
"V_inf=1; # air velocity in m/s\n",
"Re= (V_inf*L)/v # Reynolds Number\n",
"\n",
- "#(a)plot\n",
- "#delta=1.98*10**-2*x**(1/2)\n",
"import matplotlib.pyplot as plt\n",
"fig = plt.figure()\n",
"ax = fig.add_subplot(111)\n",
@@ -61,7 +56,6 @@
"plt.ylim((0,0.015))\n",
"a1=plot(x,t)\n",
"\n",
- "#(b)plot\n",
"import matplotlib.pyplot as plt\n",
"fig = plt.figure()\n",
"ax = fig.add_subplot(111)\n",
@@ -74,14 +68,12 @@
"plt.ylim((0,0.010))\n",
"a1=plot(x,t)\n",
"\n",
- "# (c)calculation of absolute viscosity\n",
"gc=1\n",
"mu=rou*v/gc\n",
"b=1 # width in m\n",
"Df=0.664*V_inf*mu*b*(Re)**0.5\n",
"\n",
"\n",
- "#result\n",
"print\"(a)plot between boundary layer growth with distance\"\n",
"print\"(b)velocity distribution with distance\"\n",
"print\"(c)The skin-drag including both sides of plate is \",round(2*Df,4),\"n\"\n"
@@ -131,10 +123,7 @@
"cell_type": "code",
"collapsed": false,
"input": [
- "# determination of temperature profile\n",
"\n",
- "#Given\n",
- "# properties of water at (40 + 100)/2 = 70\u00b0F = 68\u00b0F from appendix table C11\n",
"rou= 62.4 # density in Ibm/ft^3 \n",
"cp=0.9988 # specific heat BTU/(lbm-degree Rankine) \n",
"v= 1.083e-5 # viscosity in sq.ft/s \n",
@@ -143,10 +132,8 @@
"Pr = 7.02 # Prandtl Number\n",
"V=1.2 # velocity in ft/s\n",
"\n",
- "#Calculation\n",
"x1=1\n",
"Re1=(V*x1)/v # Reynolds Number at x=1 ft\n",
- "# since Reynolds Number is less than 5*10^5, the flow is laminar\n",
"hL1=0.664*Pr**(1/3.0)*Re1**0.5*kf/x1\n",
"Tw=100 # temperature of metal plate in degree fahrenheit\n",
"T_inf=40 # temperature of water in degree fahrenheit\n",
@@ -156,7 +143,6 @@
"print\"The heat transferred to water over the plate is\",round(q1,0),\"BTU/hr\"\n",
"x2=2\n",
"Re2=(V*x2)/v # Reynolds Number at x=1 ft\n",
- "# since Reynolds Number is less than 5*10^5, the flow is laminar\n",
"hL2=0.664*Pr**(1/3.0)*Re2**0.5*kf/x2\n",
"Tw=100 # temperature of metal plate in degree fahrenheit\n",
"T_inf=40 # temperature of water in degree fahrenheit\n",
@@ -164,7 +150,6 @@
"q2=hL2*A2*(Tw-T_inf)\n",
"print\"The heat transferred to water over the plate is \",round(q2,0),\"BTU/hr\"\n",
"\n",
- "#PLot for temprature distribution\n",
"import matplotlib.pyplot as plt\n",
"fig = plt.figure()\n",
"ax = fig.add_subplot(111)\n",
@@ -177,7 +162,6 @@
"plt.ylim((0,0.004))\n",
"a1=plot(T,y)\n",
"\n",
- "#PLot for influence of prandtl no on boundary layer thickness\n",
"import matplotlib.pyplot as plt\n",
"fig = plt.figure()\n",
"ax = fig.add_subplot(111)\n",
@@ -232,10 +216,7 @@
"cell_type": "code",
"collapsed": false,
"input": [
- "# Determination of the average convection coefficient and the total drag force exerted on the plate.\n",
"\n",
- "#Given\n",
- "# properties of air at (300 + 400)/2 = 350 K from appendix table D1\n",
"rou=0.998\t # density in kg/cu.m\n",
"cp=1009 \t\t# specific heat in J/(kg*K) \n",
"v=20.76e-6 \t# viscosity in sq.m/s \n",
@@ -247,15 +228,12 @@
"b=0.5 \t\t# width in m\n",
"Re=V*L/v \t# Reynolds number at plate end\n",
"\n",
- "#calculation\n",
- "# Nu=h*L/k= 0.664 Re**(1/2)Pr**(1/3)\n",
"h=k*0.664*Re**(0.5)*Pr**(1/3.0)/L\t # The average convection coefficient in W/(sq.m.K)\n",
"Df=0.664*V*rou*v*b*(Re)**0.5 \t # drag force in N\n",
"hx=(1/2.0)*h # local convective coefficient\n",
"delta=5*L/(Re)**0.5 # The boundary-layer thickness at plate end\n",
"delta_t=delta/(Pr)**(1/3.0)\n",
"\n",
- "#Result\n",
"print\"The local convective coefficient is \",round(hx,2),\"W/(sq.m.K)\"\n",
"print\"The boundary-layer thickness at plate end is \",round(delta*100,2),\"cm\"\n",
"print\"The thermal-boundary-layer thickness is \",round(delta_t*100,2),\"cm\""
@@ -287,10 +265,7 @@
"cell_type": "code",
"collapsed": false,
"input": [
- "# Determination of the maximum heater-surface temperature for given conditions\n",
"\n",
- "#Given\n",
- "# fluid properties at (300 degree R + 800 degree R)/2 = 550 degree R=540degree R from Appendix Table D.6\n",
"rou= 0.0812 # density in Ibm/ft^3 \n",
"cp=0.2918 # specific heat BTU/(lbm-degree Rankine) \n",
"v= 17.07e-5 # viscosity in ft^2/s \n",
@@ -298,16 +273,13 @@
"a = 0.8862 # diffusivity in ft^2/hr \n",
"Pr = 0.709 # Prandtl Number\n",
"\n",
- "#calculation\n",
"qw=10/(1.5*10.125)*(1/.2918)*144 # The wall flux \n",
"V_inf=20 # velocity in ft/s\n",
"L=1.5/12 # length in ft\n",
"Re_L=V_inf*10*L/v # Reynolds number at plate end\n",
- "# So the flow is laminar and we can find the wall temperature at plate end as follows\n",
"T_inf=300 # free stream temperature in degree Rankine\n",
"Tw=T_inf+(qw*L*10/(kf*0.453*(Re_L)**0.5*(Pr)**(1/3.0)))\n",
"\n",
- "#Result\n",
"print\"The maximum heater surface temperature is \",round(Tw,0),\"R\"\n"
],
"language": "python",
@@ -335,10 +307,7 @@
"cell_type": "code",
"collapsed": false,
"input": [
- "# validation of the equation st.(Pr)**(2/3)=Cd/2 where St: Stanton Number Pr:Prandtl Number Cd: Drag Coefficient\n",
"\n",
- "#Given\n",
- "# values of parameters from example 7.4\n",
"rou= 0.0812 # density in Ibm/ft**3 \n",
"cp=0.2918 # specific heat BTU/(lbm-degree Rankine) \n",
"v= 17.07e-5 # viscosity in ft**2/s \n",
@@ -350,14 +319,12 @@
"qw=324.0 # The wall flux in BTU/(hr.ft**2)\n",
"V_inf=20 # velocity in ft/s\n",
"\n",
- "#Calculation\n",
"hx=qw/(Tw-T_inf) # The convection coefficient\n",
"LHS=(hx/3600.0)*(Pr)**(2/3.0)/(rou*cp*V_inf)\n",
"Re_L=1.46e+005 # Reynolds number at plate end\n",
"RHS=0.332*(Re_L)**(-0.5)\n",
"err=(LHS-RHS)*100/LHS\n",
"\n",
- "#Result\n",
"print\"The convection coefficient is BTU/(hr.sq.ft.degree R)\",hx\n",
"print\"The error is \",round(err,0),\"percent\"\n",
"print\"Since the error is only 3 percent, the agreement is quite good\"\n"
@@ -389,10 +356,7 @@
"cell_type": "code",
"collapsed": false,
"input": [
- "# Estimation of the drag due to skin friction\n",
"\n",
- "#Given\n",
- "# properties of water at 68\u00b0F from Appendix Table C.11\n",
"rou= 62.4 # density in Ibm/cu.ft\n",
"v= 1.083e-5 # viscosity in sq.ft/s \n",
"V_inf=5*.5144/.3048 # barge velocity in ft/s using conversion factors from appendix table A1\n",
@@ -402,10 +366,8 @@
"gc=32.2\n",
"b=12 # width in ft\n",
"\n",
- "#Calculation\n",
"Df=(Cd*rou*V_inf**2*b*L)/(2*gc)\n",
"\n",
- "#Result\n",
"print\"The drag force is \",round(Df,0),\"lbf\"\n"
],
"language": "python",
@@ -433,10 +395,7 @@
"cell_type": "code",
"collapsed": false,
"input": [
- "# Determination of wattage requirement\n",
"\n",
- "#Given\n",
- "# properties of carbon dioxide at a film temperature of (400+600)/2 = 500 K from appendix table D2\n",
"rou= 1.0732 # density in kg/m**3 \n",
"cp= 1013 # specific heat in J/(kg*K) \n",
"v= 21.67e-6 # viscosity in m**2/s \n",
@@ -452,8 +411,6 @@
"Tw=600 # temperature of heater surface in K\n",
"T_inf=400 # temperature of carbon dioxide in K\n",
"\n",
- "#calculation\n",
- "#Nux=0.664*Rex**(1/2)*Pr**(1/3)\n",
"y=0.664*Pr**(1/3.0)*k*(vel/v)**(1/2.0) #y=h1*x1**(1/2)\n",
"x1=0.04 # m\n",
"h1=y/x1**(0.5)\n",
@@ -474,24 +431,19 @@
"Q2=h4*x4*(b)*(Tw-T_inf) #Q=q1+q2+q3+q4\n",
"q4=Q2-Q1\n",
"\n",
- "#at the end of 5th heater\n",
"Re5=vel*5*x1/(v)\n",
"\n",
- "#Nux=10.0359*(Rex**(0.8)-830)*Pr**(1/3)\n",
"h5=0.0359*(Re5**(0.8)-830)*Pr**(1/3.0)*(k/(11.9*x1))\n",
"x5=0.2\n",
"Q3=h5*x5*(b)*(Tw-T_inf) #Q3=q1+q2+q3+q4+q5\n",
"q5=Q3-Q2\n",
"\n",
- "#at the end of 6th heater\n",
"Re6=vel*6*x1/(v)\n",
- "#Nux=10.0359*(Rex**(0.8)-830)*Pr**(1/3)\n",
"h6=0.0359*(Re5**(0.8)-830)*Pr**(1/3.0)*(k/(10.3*x1))\n",
"x6=0.24\n",
"Q4=h6*x6*(b)*(Tw-T_inf) #Q4=q1+q2+q3+q4+q5+q6\n",
"q6=round(Q4,0)-round(Q3,0)\n",
"\n",
- "#Result\n",
"print\"The wattage required for 1st heater is \",round(q1,0),\"W\"\n",
"print\"The wattage required for 2nd heater is \",round(q2,0),\"W\"\n",
"print\"The wattage required for 3rd heater is \",round(q3,1),\"W\"\n",
@@ -529,10 +481,7 @@
"cell_type": "code",
"collapsed": false,
"input": [
- "# Estimation of force exerted on the pole\n",
"\n",
- "#Given\n",
- "# properties of air at given conditions from appendix table D1\n",
"rou= 0.0735 # density in Ibm/ft**3 \n",
"v= 16.88e-5 # viscosity in ft**2/s \n",
"V=20*5280/3600.0 # flow velocity in ft/s\n",
@@ -543,7 +492,6 @@
"Cd_cylinder=1.1 # value of Cd for smooth cylinder from figure 7.22\n",
"A_cylinder=D*L # frontal area of pole\n",
"\n",
- "#Calculation\n",
"Df_cylinder=Cd_cylinder*(0.5)*rou*V**2*A_cylinder/gc\n",
"D_square=2/12.0 # length of square part of pole\n",
"L_square=4\n",
@@ -579,10 +527,7 @@
"cell_type": "code",
"collapsed": false,
"input": [
- "# determination of required current\n",
"\n",
- "#Given\n",
- "# properties of air at film temperature (300 + 500)/2 = 400 K from appendix table D1\n",
"rou= 0.883 # density in kg/cu.m\n",
"cp= 1014 # specific heat in J/(kg*K) \n",
"v= 25.90e-6 # viscosity in sq.m/s \n",
@@ -596,7 +541,6 @@
"C=0.911 #value of C for cylinder from table 7.4\n",
"m=0.385 #value of m for cylinder from table 7.4\n",
"\n",
- "#calculation\n",
"hc=kf*C*(Re_D)**m*(Pr)**(1/3)/D # the convection coefficient in W/(m**2.K)\n",
"Tw=500 # air stream temperature in K\n",
"T_inf=300 # wire surface temperature in K\n",
@@ -606,7 +550,6 @@
"Resistance=resistivity*(L/(math.pi*D**2)) # resistance in ohm\n",
"i=(qw*100/Resistance)**0.5 # current in ampere\n",
"\n",
- "#Result\n",
"print\"The current is %.1f A\",round(i,1),\"A\"\n"
],
"language": "python",
@@ -634,17 +577,13 @@
"cell_type": "code",
"collapsed": false,
"input": [
- "# Calculation of the pressure drop for the air passing over the tubes and the heat transferred to the air.\n",
"\n",
- "#Given\n",
- "# properties of air at 70 + 460 = 530 degree R = 540 degree R from appendix table D1\n",
"rou= 0.0735 # density in Ibm/cu.ft \n",
"cp=0.240 # specific heat BTU/(lbm-degree Rankine) \n",
"v= 16.88e-5 # viscosity in sq.ft/s \n",
"kf = 0.01516 # thermal conductivity in BTU/(hr.ft.degree Rankine) \n",
"a = 0.859 # diffusivity in sq.ft/hr \n",
"Pr = 0.708 # Prandtl Number\n",
- "# specifications of 3/4 standard type K copper tubing from appendix table F2\n",
"OD=0.875/12 # outer diameter in ft\n",
"ID=0.06208 # inner diameter in ft\n",
"A=0.003027 # cross sectional area in sq.ft\n",
@@ -653,7 +592,6 @@
"sT=1.3/12\n",
"V_inf=12 # velocity of air in ft/s\n",
"\n",
- "#calculation\n",
"V1=(sT*V_inf)/(sT-OD) # velocity at area A1 in ft/s\n",
"sD=((sL)**2+(sT/2)**2)**0.5 # diagonal pitch in inch\n",
"V2=(sT*V_inf)/(2*(sD-OD))\n",
@@ -676,7 +614,6 @@
"T_inf=70 # air temperature in degree F\n",
"q=hc*As*(Tw-T_inf) # heat transferred\n",
"\n",
- "#result\n",
"print\"The pressure drop is \",round(dP/147,3),\"psi\"\n",
"print\"The heat transferred is\",round(q,1),\" BTU/hr\"\n"
],
generated by cgit (git 2.34.1) at 2025-04-08 00:03:12 +0000