BLOG: Entry Number Five

GUILTY: it’s been awhile…

With all of the things that happened last week, we completely forgot to update our blog (it’s been ELEVEN DAYS). But once I start explaining what all has happened since, it’ll be evident why the blog was neglected.

After finding Steve, we acquired some materials from him that would be useful for some preliminary results. Before starting the experiments, we finished our Solidworks thermal simulations with satisfactory results and created our midterm presentation. We think that we did great on our midterm presentation. In order to run the tests on the test rig that Steve gave us, we needed a hot water source and a cold water source. We relocated to the Fluid Mechanics lab and set up the test rig there.

Since then, we have been running tests everyday on this test rig. We measure the temperature going in and the temperature going out on both the hot and the cold side of the specimen-we are using nylon since its thermal conductivity is known. Using the volumetric flow rate, density, specific heat constant, and change in temperature, we can calculate the rate of the heat transfer (Q dot). Using Q dot, we can then find the thermal resistance with

R=(change of T / Q dot).

With the R value, we can find the thermal conductivity (k) by using

k=(length / (R*A))

By conducting the experiment over and over, we narrowed down the errors and found the correct configurations for the apparatus to function as desired. Next, We insulated the heat exchanger plates on the top and bottom to minimize the error further. Doing so gave us fairly accurate values with a margin of about 10%. Our next experiment was to see if minimizing the contact resistance would decrease our percentage of error, and if so, what is the amount of force that we need to apply to optimize the results. We ran tests at 50, 75, 100, 150, and 200 pounds. We found that at 50 pounds, the values were the most accurate. To further improve our data, we decided to insulate the sides of the plates and specimen as well in order to minimize heat loss. Tests have yet to be ran for this setup.

Through all of these experiments, we also had our midterm presentation, a field trip to the Chrysler Wind Tunnel, and the Young Automotive Professional Conference to attend, so please forgive us for neglecting the blog this past week.

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