{
"cells": [
{
"cell_type": "markdown",
"metadata": {},
"source": [
"# Chapter 7 : External Forced Convection"
]
},
{
"cell_type": "markdown",
"metadata": {},
"source": [
"### Example 7.1"
]
},
{
"cell_type": "code",
"execution_count": 1,
"metadata": {
"collapsed": false
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"We have laminar flow over the entire plate\n",
"(0.006630019984886925, 'The average friction coefficient is')\n",
"The drag force acting on the plate per unit width is 58.0789750676 N\n",
"Nusselt Number is 133.200201811\n",
"Convective heat transfer coefficient is 3.84682182831 W/m**.degree Celcius\n",
"Heat flow rate is 769.0 W\n"
]
}
],
"source": [
"\n",
"import math \n",
"# Flow of hot oil over a Flat Plate\n",
"\n",
"# Variables\n",
"T_oil = 60\t\t\t#Temp of engine oil[degree Celcius]\n",
"T_plate = 20\t\t\t#Temp of flat plate[degree Celcius]\n",
"Rec = 5*10**5\t\t\t#Critical reynolds number for laminar flow\n",
"Tf = (T_oil+T_plate)/2\t\t\t#Film temperature[degree Celcius]\n",
"v = 2\t\t\t#[m/s]\n",
"#Properties of engine oil at film temperature\n",
"rho = 876\t\t\t#[kg/m**3]\n",
"Pr = 2962\t\t\t#Prandtl number\n",
"k = 0.1444\t\t\t#[W/m.degree Celcius]\n",
"nu = 2.485*10**(-4)\t\t\t#dynamic vismath.cosity[m**2/s]\n",
"L = 5\t\t\t#Length of plate[m]\n",
"\n",
"# Calculations and Results\n",
"ReL = (v*L)/nu;\n",
"if(ReLReC):\n",
" print (\"Flow is not laminar\")\n",
" #We have average Nusselt Number\n",
" Nu1 = ((0.037*(ReL1**(0.8)))-871)*(Pr**(1/3));\n",
" print \"Nusselt Number is\",Nu1\n",
" h1 = k*Nu1/L1\t\t\t#[W/m**2.degree Celcius]\n",
" As1 = w1*L1\t\t\t #Flow Area of plate[m**2]\n",
" Q1 = h1*As1*(T_plate-T_air);\n",
" print \"Heat Flow Rate is\",Q1,\"W\"\n",
"else:\n",
" print (\"Flow is laminar\")\n",
"\n",
"#Solution(b)\n",
"L2 = 1.5\t \t\t#Characteristic length of plate along flow of air[m]\n",
"ReL2 = v*L2/nu_ac\t\t\t#Reynolds Number\n",
"if(ReL2