MIET2039_CL03-Processing-Condensation-Experimental-Data.ipynb

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    "<h3 style=\"color:navy;\">MIET2039 Computer Lab 03 - Processing Condensation Experimental Data - Solution</h3>\n",
    "A condensation experimental test was performed and both film and dropwise condensation phenemonon was produced. A vertical plate (<em>height of 13cm, width of 3cm</em>) is placed in a chamber filled with hot vapour. The vertical plate has cold water running through it at a given flow rate. This produces a plate surface temperature lower than the vapour saturation temperature. Heat is absorbed by the flowing water and its temperature change is caused by the condensation heat transfer.\n",
    "<img src=\"img/condensation-CL03.png\" width=\"500px\"/>\n",
    "\n",
    "We will relate the heat transfer gained by the colder fluid to the condensation heat transfer coefficient. In this experiment, the following data were measured:\n",
    "<em>\n",
    "* <span style=\"color:#CD5C5C\">Flowrate L/min (column 0)</span>\n",
    "* <span style=\"color:#CD5C5C\">T<sub>in</sub> water temperature at inlet (column 1)</span>\n",
    "* <span style=\"color:#CD5C5C\">T<sub>out</sub> water temperature at exit (column 2)</span>\n",
    "* <span style=\"color:#CD5C5C\">T<sub>sat</sub> saturation temperature (column 3)</span>\n",
    "* <span style=\"color:#CD5C5C\">T<sub>surf</sub> plate surface temperature (column 4) </span>\n",
    "</em>\n",
    "\n",
    "As an example of the data, the file <em>dropwise_06.dat</em> looks like this:\n",
    "<pre>\n",
    "Flow\tTin\tTout\tTsat\tTsurf\n",
    "1.5\t14.4\t40\t71\t55\n",
    "1.5\t14.4\t40\t70.5\t55\n",
    "1.5\t14\t44.5\t71.1\t52.6\n",
    "1.5\t13.6\t47.4\t71.4\t50\n",
    "1.5\t13.7\t48.9\t71.2\t51\n",
    "</pre>\n",
    "\n",
    "#### Scripting for automating analysis:\n",
    "In experimental work large amounts of data sets are often gathered. Without the use of scripting tools a naive experimentalist would probably process each data file manually. If this data set happens to contain hundreds of files then this is a problem. In this session we look at ways to automate processing experimental. \n",
    "#### Some new python commands\n",
    "* We will use the <strong>glob</strong> module which helps us find files matching a specified pattern\n",
    "* We will use numpy arrays. Array dimensions need to be pre-defined before performing actions on it.\n",
    "* Our data files containing the experimental data have five columns and 3 to 5 rows of data\n",
    "* Our strategy is to read the contents of each file and store it into a numpy array using the append method\n",
    "* We initialize an empty array 0,5 with np.empty((0,5))"
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    "<p style=\"color:#4799ff;\">EXERCISE 3.1</p>\n",
    "* import glob\n",
    "* find all files in your folder with the word drop in the filename and an extension .dat\n",
    "* store them in a list and then print the list out to make sure you have the correct files"
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   "source": [
    "# import glob ... or.... import glob as gb\n",
    "# use * as wildcard to create pattern filename search\n"
   ]
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    "<p style=\"color:#4799ff;\">EXERCISE 3.2</p>\n",
    "* import numpy as np\n",
    "* create an empty array with dimensions 0x5 (0 rows, 5 columns)\n",
    "<pre> np.empty((0,5)) </pre> \n",
    "* read data from a file by using <pre>np.loadtxt(filename, skiprows=x)</pre>\n",
    "* append the data that was read into the initialized array by using <pre>np.append(arrayAppendingTo, dataToAppend, axis=0)</pre>\n",
    "axis = 0 means append vertically down, axis = 1 appends horizontally\n",
    "* print the new array to confirm that you have appended the data together"
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    "<p style=\"color:#4799ff;\">EXERCISE 3.3</p>\n",
    "* Here we make use of an iterative loop to automate the data import\n",
    "* Use a for loop to repeatedly import data from the data files you located from glob.glob command, and append each data set into an array\n",
    "* e.g. \n",
    "<pre>\n",
    "for i in fileList:\n",
    "   .....\n",
    "</pre>"
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    "#### Calculations for Heat Transfer\n",
    "* Flow rate conversion to SI units (can you remember this one?\n",
    "* Change in energy of cooling water in the plate (equal to heat transfer rate):  $$\\dot{Q} = \\dot{m}C_p \\Delta T_{exit - in}$$\n",
    "* Convert heat transfer rate to heat flux (e.g. divide by the vertical plate surface area):\n",
    "$$\\dot{q} = \\frac{\\dot{Q}}{ A} $$\n",
    "$$h = \\frac{\\dot{q}}{\\Delta T_{sat - surf}}$$\n",
    "\n",
    "<p style=\"color:#4799ff;\">EXERCISE 3.4</p>\n",
    "* Since we have used arrays, we can perform scalar calculations on it.\n",
    "* Use the heat transfer equations from above and determine the heat transfer coefficient for each set of data.\n",
    "* e.g. <pre>Qdot = allData[:,0]/60 \\* 4186 * (allData[:,2]-allData[:,1])</pre>\n",
    "careful here since Python starts arrays with index of 0 not 1\n",
    "\n",
    "* The surface area of the vertical plate was defined is 0.13m x 0.03m = 0.0039m^2\n",
    "* Conversion from L/min to kg/s is approximately achieved by dividing by 60 since 1L ~ 1kg\n",
    "* Cp of water is 4186 J/kgK"
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    "<p style=\"color:#4799ff;\">EXERCISE 3.5</p>\n",
    "* Use matplotlib module to plot the heat transfer coefficient vs temperature difference between vertical plate surface and saturation temperature\n",
    "e.g\n",
    "<pre>\n",
    "from matplotlib import pyplot as plt\n",
    "%matplotlib inline\n",
    "....\n",
    "</pre>"
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    "<p style=\"color:#4799ff;\">EXERCISE 3.6</p>\n",
    "* Repeat the analysis for filmwise condensation\n",
    "* Plot its heat transfer coefficient\n",
    "* Look at the two plots and comment on the differences between the plots!"
   ]
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    "#### Discussion Questions\n",
    "1. Describe the heat transfer coefficient profile for dropwise and filmwise condensation.\n",
    "\n",
    "2. Which mode of condensation produces a higher heat transfer coefficient\n",
    "\n",
    "3. From the lecture (and thermal resistance theory) explain the cause for the different heat transfer coefficients in the different condensation modes."
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