diff options
Diffstat (limited to 'Engineering_Heat_Transfer/CHAPTER9.ipynb')
| -rw-r--r-- | Engineering_Heat_Transfer/CHAPTER9.ipynb | 89 |
1 files changed, 0 insertions, 89 deletions
diff --git a/Engineering_Heat_Transfer/CHAPTER9.ipynb b/Engineering_Heat_Transfer/CHAPTER9.ipynb index c1ada237..d66004ef 100644 --- a/Engineering_Heat_Transfer/CHAPTER9.ipynb +++ b/Engineering_Heat_Transfer/CHAPTER9.ipynb @@ -27,24 +27,16 @@ "cell_type": "code",
"collapsed": false,
"input": [
- "# determination of counterflow and parallel-flow configurations. \n",
"\n",
- "#Given\n",
- "# temperatures of hot fluid in degree C\n",
"T1=100.0 \n",
"T2=75.0\n",
- "# temperatures of cold fluid in degree C\n",
"t1=5.0\n",
"t2=50.0\n",
"\n",
- "#Calculation\n",
- "# for counterflow\n",
"import math\n",
"LMTD_counter=((T1-t2)-(T2-t1))/(math.log((T1-t2)/(T2-t1)))\n",
- "# for parallel flow\n",
"LMTD_parallel=((T1-t1)-(T2-t2))/(math.log((T1-t1)/(T2-t2)))\n",
"\n",
- "#Result\n",
"print\"The LMTD for counter flow configuration is \",round(LMTD_counter,1),\"C\"\n",
"print\"The LMTD for parallel flow configuration is \",round(LMTD_parallel,2),\"C\""
],
@@ -74,24 +66,16 @@ "cell_type": "code",
"collapsed": false,
"input": [
- "# Determination of the LMTD for both counterflow and parallel-flow configurations. \n",
"\n",
- "#Given\n",
- "# temperatures of hot fluid in degree F\n",
"T1=250\n",
"T2=150\n",
- "# temperatures of cold fluid in degree F\n",
"t1=100\n",
"t2=150\n",
"\n",
- "#calculation\n",
- "# for counterflow\n",
"import math\n",
"LMTD_counter=((T1-t2)-(T2-t1))/(math.log((T1-t2)/(T2-t1)));\n",
- "# for parallel flow\n",
"LMTD_parrelel=0\n",
"\n",
- "#Result\n",
"print\"The LMTD for counter flow configuration is\",round(LMTD_counter,1),\"C\"\n",
"print\"if parallel flow is to give equal outlet temperatures,then the area needed must be infinite which is not feasible economically.\"\n",
"print\"The LMTD for parrelel flow configuration is\",LMTD_parrelel,\"C\"\n"
@@ -123,10 +107,7 @@ "cell_type": "code",
"collapsed": false,
"input": [
- "# Determination of the outlet temperature of the ethylene glycol for counterflow.\n",
"\n",
- "#Given\n",
- "# properties of air at (195 + 85)/2 = 140\u00b0F. from appendix table CII\n",
"rou_1= 0.985*62.4 # density in lbm/ft**3 \n",
"cp_1=0.9994 # specific heat BTU/(lbm-degree Rankine) \n",
"v_1= 0.514e-5 # viscosity in ft**2/s \n",
@@ -135,7 +116,6 @@ "Pr_1 = 3.02 # Prandtl Number \n",
"m_1=5000 # mass flow rate in lbm/hr\n",
"T_1=195 # temperature in degree F\n",
- "# properties of ethylene glycol at 140 degree F from Appendix Table C.5\n",
"rou_2= 1.087*62.4 # density in lbm/ft**3 \n",
"cp_2=0.612 # specific heat BTU/(lbm-degree Rankine) \n",
"v_2= 5.11e-5 # viscosity in ft**2/s \n",
@@ -144,32 +124,25 @@ "Pr_2 = 51 # Prandtl Number \n",
"m_2=12000 # mass flow rate in lbm/hr\n",
"T_2=85 # temperature in degree F\n",
- "# specifications of seamless copper water tubing (subscripts: a = annulus, p = inner pipe or tube) from appendix table F2\n",
"ID_a=0.1674\n",
"ID_p=0.1076\n",
"OD_p=1.375/12\n",
- "# Flow Areas\n",
"A_p=math.pi*ID_p**2/4\n",
"A_a=math.pi*((ID_a)**2-(OD_p)**2)/4\n",
"\n",
- "# Annulus Equivalent Diameters\n",
"D_h=ID_a-OD_p\n",
"D_e=(ID_a**2-OD_p**2)/(OD_p)\n",
"\n",
- "# Reynolds Numbers \n",
"Re_1=(m_1/3600.0)*(ID_p)/(v_1*rou_1*A_p)\n",
"Re_2=(m_2/3600.0)*(D_e)/(v_2*rou_2*A_a)\n",
"\n",
- "# Nusselt numbers\n",
"Nu_1=0.023*(Re_1)**(4/5.0)*(Pr_1)**0.3\n",
"Nu_2=0.023*(Re_2)**(4/5.0)*(Pr_2)**0.4\n",
"\n",
- "# Convection Coefficients \n",
"h_1i=Nu_1*kf_1/ID_p\n",
"h_1o=h_1i*ID_p/OD_p\n",
"h_2=Nu_2*kf_2/D_e\n",
"\n",
- "# Exchanger Coefficient \n",
"Uo=1/((1/h_1o)+(1/h_2))\n",
"R=(m_2*cp_2)/(m_1*cp_1)\n",
"L=20\n",
@@ -205,11 +178,7 @@ "cell_type": "code",
"collapsed": false,
"input": [
- "# Determination of (a) no. of exchangers required, (b) the overall coefficient of (all) the exchanger(s), and (c) the pressure drop for each stream. \n",
"\n",
- "#Given\n",
- "# assuming counterflow arrangement\n",
- "# properties of air at 323 K. from appendix table D1\n",
"rou_1= 1.088 \t\t# density in kg/m**3 \n",
"cp_1= 1007\t\t # specific heat in J/(kg*K) \n",
"v_1= 18.2e-6\t\t # viscosity in m**2/s \n",
@@ -217,10 +186,8 @@ "kf_1= 0.02814 \t\t# thermal conductivity in W/(m.K)\n",
"a_1 = 0.26e-4 \t\t# diffusivity in m**2/s \n",
"m_1=100 \t\t # mass flow rate in kg/hr\n",
- "# temperatures in K\n",
"t1_air=20+273 \n",
"t2_air=80+273\n",
- "# properties of carbon dioxide at [600 + (20 + 273)]/2 = 480 = 500 K. from appendix table D2\n",
"rou_2= 1.0732\t\t # density in kg/m**3 \n",
"cp_2= 1013 \t\t# specific heat in J/(kg*K) \n",
"v_2= 21.67e-6 \t #viscosity in m**2/s \n",
@@ -228,71 +195,53 @@ "kf_2= 0.03352 \t\t# thermal conductivity in W/(m.K)\n",
"a_2 = 0.3084e-4 \t\t# diffusivity in m**2/s \n",
"m_2=90\t\t\t # mass flow rate in kg/hr\n",
- "# temperatures in K\n",
"T1_CO2=600 \n",
- "# specifications of seamless copper tubing from appendix table F2\n",
"ID_a=.098\n",
"ID_p=.07384\n",
"OD_p=.07938\n",
"\n",
- "#calculation\n",
"import math\n",
- "# Flow Areas\n",
"A_p=math.pi*ID_p**(2)/4.0\n",
"A_a=math.pi*((ID_a)**2-(OD_p)**2)/4.0\n",
"\n",
- "# Heat Balance \n",
"q_air=(m_1/3600.0)*(cp_1)*(t2_air-t1_air)\n",
"T2_CO2=T1_CO2-(q_air/(m_2*cp_2/3600.0))\n",
"\n",
- "# Log-Mean Temperature Difference\n",
"LMTD_counter=((T1_CO2-t2_air)-(T2_CO2-t1_air))/(log((T1_CO2-t2_air)/(T2_CO2-t1_air)))\n",
- "# Annulus Equivalent Diameters\n",
"D_h=ID_a-OD_p\n",
"D_e=(ID_a**2-OD_p**2)/(OD_p)\n",
"\n",
- "# Reynolds Numbers \n",
"Re_1=(m_1/3600.0)*(ID_p)/(v_1*rou_1*A_p)\n",
"Re_2=(m_2/3600.0)*(D_e)/(v_2*rou_2*A_a)\n",
"\n",
- "# Nusselt numbers\n",
"Nu_1=0.023*(Re_1)**(0.8)*(Pr_1)**0.3\n",
"Nu_2=0.023*(Re_2)**(0.8)*(Pr_2)**0.4\n",
"\n",
- "# Convection Coefficients \n",
"\n",
"h_1i=Nu_1*kf_1/ID_p\n",
"h_1o=h_1i*ID_p/OD_p\n",
"h_2=Nu_2*kf_2/D_e\n",
"\n",
- "# Fouling Factors in (m**2.K)/W\n",
"Rd_air=0.0004\n",
"Rd_CO2=0.002\n",
"\n",
- "# exchanger coefficients\n",
"Uo=1/((1/h_1o)+(1/h_2))\n",
"Uo=1/((1/Uo)+Rd_air+Rd_CO2)\n",
"\n",
- "# area required\n",
"A=q_air/(Uo*LMTD_counter)\n",
"\n",
- "# surface area of one exchanger is A=math.pi*OD*L, so\n",
"L=(A/(math.pi*OD_p)) # length of each exchanger\n",
"L_available=2 # available exchanger length\n",
"N=L_available/L # no. of exchangers\n",
"\n",
- "#friction factors\n",
"fp=0.0245 #friction factor for air fom figure 6.14 corresponding to Re\n",
"fa=0.033 #friction factor for cCO2fom figure 6.14 corresponding to Re\n",
- "# Velocities\n",
"V_air=(m_1/3600.0)/(rou_1*A_p)\n",
"V_CO2=(m_2/3600.0)/(rou_2*A_a)\n",
"\n",
- "# pressure drops\n",
"dP_p=(fp*L_available*rou_1*V_air**2)/(ID_p*2)\n",
"dP_a=((rou_2*V_CO2**2)/2.0)*((fa*L_available/D_h)+1)\n",
"\n",
- "#Result\n",
"print\"(a)The number of exchangers is \",round(N,0)\n",
"print\"(b)The overall exchanger coefficient is \",round(Uo,1),\" W/(sq.m.K)\"\n",
"print\"(c)The pressure drop for tube side is \",round(dP_p,2),\"Pa\"\n",
@@ -326,10 +275,7 @@ "cell_type": "code",
"collapsed": false,
"input": [
- "# Determination of the outlet temperature of the distilled water and the pressure drop for each stream. \n",
"\n",
- "#Given\n",
- "# properties of (distilled) water at 104\u00b0F from appendix table CII\n",
"rou_1= 0.994*62.4 # density in lbm/ft**3 \n",
"cp_1=0.998 # specific heat BTU/(lbm-degree Rankine) \n",
"v_1= 0.708e-5 # viscosity in ft**2/s \n",
@@ -338,7 +284,6 @@ "Pr_1 = 4.34 # Prandtl Number \n",
"m_1=170000 # mass flow rate in lbm/hr\n",
"T1=110.0 # temperature in degree F\n",
- "# properties of (raw) water at 68\u00b0F from Appendix Table C11\n",
"rou_2= 62.4 # density in lbm/ft**3 \n",
"cp_2=0.9988 # specific heat BTU/(lbm-degree Rankine) \n",
"v_2= 1.083e-5 # viscosity in ft**2/s \n",
@@ -347,40 +292,32 @@ "Pr_2 = 7.02 # Prandtl Number \n",
"m_2=150000 # mass flow rate in lbm/hr\n",
"t1=65 # temperature in degree F\n",
- "# specifications of 3/4-in-OD, 18-BWG tubes, from table 9.2\n",
"OD=3/(4*12.0)\n",
"ID=0.652/12.0\n",
"OD_p=1.375/12.0\n",
"Nt=224.0 # from table 9.3\n",
"Np=2 # no. of tube passes\n",
- "# Shell dimensions and other miscellaneous data\n",
"Ds=17.25/12.0\n",
"Nb=15.0 # no. of baffles\n",
"B=1\n",
"sT=15/(16*12.0)\n",
"C=sT-OD\n",
"\n",
- "#CALCULATION\n",
"import math\n",
- "# flow areas\n",
"At=(Nt*math.pi*ID**2)/(4*Np)\n",
"As=(Ds*C*B)/sT\n",
"\n",
- "# Shell Equivalent Diameter \n",
"De=4*((sT/2.0)*(0.86*sT)-(math.pi*OD**2/8.0))/(math.pi*OD/2.0)\n",
"\n",
- "# Reynolds Numbers \n",
"Re_s=(m_1/3600.0)*(De)/(v_1*rou_1*As)\n",
"Re_t=(m_2/3600.0)*(ID)/(v_2*rou_2*At)\n",
"\n",
- "# Nusselt numbers\n",
"Nu_t=0.023*(Re_t)**(0.8)*(Pr_2)**0.4\n",
"Nu_s=0.36*(Re_s)**(0.55)*(Pr_1)**(1/3.0)\n",
"h_ti=Nu_t*kf_2/ID\n",
"h_to=h_ti*ID/OD\n",
"h_s=Nu_s*kf_1/De\n",
"\n",
- "# Exchanger Coefficient \n",
"Uo=1/((1/h_to)+(1/h_s))\n",
"R=(m_2*cp_2)/(m_1*cp_1)\n",
"L=16\n",
@@ -389,20 +326,16 @@ "S=0.58 #value of S from fig. 9.13 Ten Broeck graph corresponding to the value of (UoAo)/(McCpc)\n",
"t2=S*(T1-t1)+t1\n",
"T2=T1-R*(t2-t1)\n",
- "#friction factors\n",
"ft=0.029 #friction factor for raw water fom figure 6.14 corresponding to Reynolds Number calculated above\n",
"fs=0.281 #friction factor for distilled water fom figure 6.14 corresponding to Reynolds Number calculated above\n",
"\n",
- "# Velocities\n",
"V_t=(m_2/3600.0)/(rou_2*At)\n",
"V_s=(m_1/3600.0)/(rou_1*As)\n",
"\n",
- "# pressure drops\n",
"gc=32.2\n",
"dP_t=(rou_2*V_t**2)*((ft*L*Np/ID)+4*Np)/(2*gc)\n",
"dP_s=((rou_1*V_s**2)*(fs*Ds*(Nb+1)))/(2*gc*De)\n",
"\n",
- "#Result\n",
"print\"Outlet Temperatures of raw water is \",round(t2,1),\"F\"\n",
"print\"Outlet Temperatures of distilled water is \",round(T2,1),\"F\"\n",
"print\"\\nThe pressure drop for tube side is\",round(dP_t/147,1),\"psi\"\n",
@@ -424,26 +357,18 @@ "cell_type": "code",
"collapsed": false,
"input": [
- "# Using the effectiveness-NTU method to calculate the outlet temperatures of the fluids\n",
"\n",
- "#Given\n",
- "# Data from Example 9.5\n",
- "# properties of (distilled) water at 104\u00b0F \n",
"m_1=170000 \t\t# mass flow rate in lbm/hr\n",
"T1=110 \t\t\t# temperature in degree F\n",
"cp_1=0.998\t\t # specific heat BTU/(lbm-degree Rankine) \n",
- "# properties of (raw) water at 68\u00b0F \n",
"m_2=150000 \t\t# mass flow rate in lbm/hr\n",
"t1=65 \t\t\t# temperature in degree F\n",
"cp_2=0.9988\t # specific heat BTU/(lbm-degree Rankine) \n",
"Uo=350 \t\t\t# exchanger coefficient\n",
"Ao=703.7\n",
- "# The effectiveness-NTU approach is used when the overall heat transfer coefficient is known\n",
- "# determining the capacitances\n",
"mcp_raw=m_2*cp_2\n",
"mcp_distilled=m_1*cp_1\n",
"\n",
- "# determination of parameters for determining effectiveness\n",
"mcp_min_max=mcp_raw/mcp_distilled\n",
"UA_mcpmin=(Uo*Ao)/(mcp_raw)\n",
"effectiveness=0.58 \t\t#value of effectiveness from figure 9.15 corresponding to the above calculated values of capacitance ratio and (UoAo/mcp_min)\n",
@@ -452,7 +377,6 @@ "t2=(q/mcp_raw)+t1\n",
"T2=T1-(q/mcp_distilled)\n",
"\n",
- "#Result\n",
"print\"The Outlet temperature is Raw Water is\",round(t2,1),\"F\"\n",
"print\"The Outlet temperature is disilled Water is\",round(T2,1),\"F\"\n"
],
@@ -482,8 +406,6 @@ "cell_type": "code",
"collapsed": false,
"input": [
- "# (a) Determine the UA product for the exchanger. (b) Calculate the exit temperatures for the exchanger, assuming that only the inlet temperatures are known\n",
- "# properties of engine oil at (190 + 158)/2 = 174\u00b0F = 176 degree F from appendix table C4\n",
"rou_1= 0.852*62.4\t\t # density in lbm/ft**3 \n",
"cp_1=0.509\t\t # specific heat BTU/(lbm-degree Rankine) \n",
"v_1=0.404e-3 \t\t# viscosity in ft**2/s \n",
@@ -491,10 +413,8 @@ "a_1=2.98e-3 \t# diffusivity in ft**2/hr \n",
"Pr_1=490.0 \t\t# Prandtl Number \n",
"m_1=39.8 \t\t # mass flow rate in lbm/min\n",
- "# temperatures in degree F\n",
"T1=190.0\n",
"T2=158.0\n",
- "# properties of air at (126 + 166)/2 = 146\u00b0F = 606 degree R from appendix table D1\n",
"rou_2= 0.0653\t\t # density in lbm/ft**3 \n",
"cp_2=0.241\t\t # specific heat BTU/(lbm-degree Rankine) \n",
"v_2= 20.98e-5 \t\t# viscosity in ft**2/s \n",
@@ -502,38 +422,29 @@ "a_2 = 1.066 \t\t# diffusivity in ft**2/hr \n",
"Pr_2 = 0.706 \t\t# Prandtl Number \n",
"m_2=67.0 \t\t\t# mass flow rate in lbm/min\n",
- "# temperatures in degree F\n",
"t1=126.0\n",
"t2=166.0\n",
- "# Heat Balance\n",
"q_air=m_2*cp_2*60*(t2-t1)\n",
"q_oil=m_1*cp_1*60*(T1-T2)\n",
"\n",
- "# for counterflow\n",
"import math\n",
"LMTD=((T1-t2)-(T2-t1))/(math.log((T1-t2)/(T2-t1)))\n",
- "# Frontal Areas for Each Fluid Stream\n",
"Area_air=(9.82*8)/144.0\n",
"Area_oil=(3.25*9.82)/144.0\n",
"\n",
- "# Correction Factors (parameters calculated first)\n",
"S=(t2-t1)/(T1-t1)\n",
"R=(T1-T2)/(t2-t1)\n",
"F=0.87 #value of correction factor from figure 9.21a corresponding to above calculated values of S and R\n",
- "# Overall Coefficient (q = U*A*F*LMTD)\n",
"UA=q_air/(F*LMTD)\n",
- "# determining the capacitances\n",
"mcp_air=m_2*cp_2*60\n",
"mcp_oil=m_1*cp_1*60\n",
"\n",
- "# determination of parameters for determining effectiveness\n",
"mcp_min_max=mcp_air/mcp_oil\n",
"NTU=(UA/mcp_air)\n",
"effectiveness=0.62 \t\t#effectiveness from fig 9.21b corresponding to the values of capacitance ratio \n",
"t2_c=(T1-t1)*effectiveness+t1\n",
"T2_c=T1-(mcp_air)*(t2_c-t1)/(mcp_oil)\n",
"\n",
- "#Result\n",
"print\"The Overall Coefficient is \",round(UA,0),\" BTU/(hr. degree R)\"\n",
"print\"Calculated outlet temprature are:\"\n",
"print\"Outlet temprature for air\",round(t2_c,1),\"F\"\n",
|