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BLOG: Entry Number Seven

The First Step to Recovery is Admitting You Have a Problem

Problem: we keep forgetting to update the blog.¬†Recovery Progress: it’s only been 9 days. WE ARE IMPROVING. The issue here is that A LOT has happened since we redesigned our box. We started the building process!

While waiting for the patch heater to arrive, we started cutting out insulation boards based on the Solidworks design. We decided that initially, we will only be building the hot side of the box. The insulation that we acquired for free were all 48 inches long but their widths varied anywhere from 4 inches to 29 inches. This made things difficult as the panels (top, bottom, sides, and back) required several pieces of insulation puzzled together to the right dimensions. It took us several days to get all of the pieces needed, but alas, all 49 pieces were cut. One of the biggest problems that we faced had to do with the design of the box itself. in the design there is an insertion slot for the specimen, a crucial element to keep it air tight. The machines in the machine shop were not suitable to cut these small corners off of the pieces of insulation. But Michael had the idea of using a hot knife. Dr. Kobus went to go pick one up from Sears and we were back in business! Just kidding. The knife did not work. the blade was too short to be useful in our application. Leanna went to the machine shop, filed down a threaded rod until it was flat (like a knife!) and attempted to use this as the new blade. But then we found that the problem was that the heat on the hot knife could only travel about an inch down the blade, leaving the tip cool. Leanna has another strange idea and well, it looks like this.IMG_7951

Using the propane torch, she heated the make-shift blade on the hot knife and cut the insertion out of the insulation (Hurray!).

We were advised by Dr. Kobus not to use glue when putting together our box just yet. He told us to place the pieces where they needed to go and then use ratchet scraps to compress the pieces together. We did as told with a few minor difficulties. Once the box was complete, we squeezed the sample into place and the completed half-box is shown in the featured picture.

With the box in the correct configuration, we had to make thermocouples for each side of the specimen. With some time and patience, we were able to make 6 thermocouples. Three on each side of the specimen. We are currently trying to figure out the best way to implement the heat source into the box. We were provided a heat gun from Matt, the lab manager, but the heat gun may be too hot, in which case, we would need to hook it up to a variac to lower the power output, therefore producing less heat.

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BLOG: Entry Number Six

And We Felt Bad About 11 Days Last Time…

So the last blog entry was about how guilty we felt about not updating our blog for 11 days. News flash! We beat the record. It’s been 14 days this time, but the guilt is significantly less. Last time, our reason for not updating our blog was because there was so much going on that we didn’t have time to. This time, however, it’s the opposite. Barely anything has happened since we last updated. We’ll explain.

So we left off last time thinking that we should insulate the sides of the specimen for even more accurate numbers. We were very wrong. Insulating the sides didn’t help; it made it a lot worse. Why? Thermal bridging. Before, when we ran the tests with the sides open to the air, the hot side loss a little heat and the cold side gained a little heat, but all was well and the change was not drastic enough to fret over. But by insulating the sides, we allowed the trapped heat that would’ve been lost to the surrounding to travel along the inner surface of the side insulation and heat up the cold plate, causing the temperatures to be off and messing up the data. Seeing how horrible the idea was, we threw it aside and ran the tests sideless like before.

Tired of documenting and calculating data by hand, Leanna created a spreadsheet that did all of the calculations for the thermal conductivity by inputting four temperatures. 5 trials were conducted for each weight (25 to 200, in increments of 25). The results were not so pleasing. This time, we found that as you increase the weight applied, the thermal conductivity increases as well. So we were getting the expected value at around 25 or 50 pounds, but any more weight than that and the percent error got up to 35%.

Finding this strange, Professor Kobus taught us how to calculate uncertainty of measurement tools to see how accurate of an experiment this was. Using this new knowledge, we found the experimental uncertainty to be over plus or minus 45%. This scared us a little, but it was also relieving to know that our messed up numbers were within the uncertainty range.

After ¬†finishing up all of the test with the Nylon specimen, we moved on to another type of specimen. Michael went down to the Machine Shop and cut us a new Aluminum specimen. Through a few trials with this new specimen, we learned that it was not possible to yield correct values from our apparatus because of conjugate heat transfer. Our experiment is limited to the building’s hot water and cold water and a large change in temperature is not possible to control using water. Knowing this, we theorized that if we were to replace the hot plate with patch heaters, we would be able to heat the specimen up to a higher temperature, yielding a larger change in temperature, and maybe get correct results in the process.

The patch heater is currently shipping so until then, experimentation and data will come to a halt.

Work never ends, because as we wait for the patch heater, we are going to be redesigning our box for easier insertion of the specimen. The new finished design is pictured in the blog image.

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.

BLOG: Entry Number Four

WALDO HAS BEEN FOUND

A lot has happened between the last post and this one. Dr. Guessous managed to find time for us! (Thank you!) She came to our lab and gave us some advise for what program we should use for the level of accuracy that we want from this simulation. Since we are only trying to get a rough guess, she said Fluent may be unnecessary and that Solidworks should work fine for what we want. (Whew!) We are relieved because from watching tutorials and fiddling around with Fluent, we inferred that it has a high learning curve, which would have cost us up to a week to be able to utilize it for our simulations. Dr. Guessous also gave us some pointers as to what ¬†thermal loads we should be applying and where. We found that we had not accounted for radiation in our previous simulations and that is why we weren’t getting the right colors to appear. With time and a little more experimenting, we should be able to get a rough simulation of our hot box apparatus.

The BIGGEST change since last is that WALDO HAS BEEN FOUND. We caught Dr. Steve Bazinski right as he was leaving the Fuel Cell lab and was about to disappear into the abyss once more. We didn’t know it was him. We were at the very end of the hallway, when we saw a guy walk out of that lab. Not knowing whether or not this was the right guy, Leanna just yelled “STEVE????” and lucky for her, he turned around. We met with him in the lab and discussed about the heat flux sensors that he has. Dr. Meng Xu had given us one of them a few days before, but when we tested it with the Multimeter, the voltage never changed. Steve gave us another sensor and told us about his thermal conductivity test rig that we could use to get some rough comparisons if we wanted. We then went to Matt Bruer’s office to test out this sensor and this time, it worked! AS to why the first one didn’t work, we think it might be because at first, Michael accidentally hooked it up to a Power Supply and pushed 15 volts through it. It probably fried the sensor.

Two of our problems solved in one day! Now all we need to do is to accurately set up the simulation and work through all the problems with that.

Also, we didn’t take any pictures this time, (We should have taken one of Steve!) so up top is a picture of Bruce, the department dog, chewing a frisbee.

BLOG: Entry Number Three

Has anybody seen Waldo?

By Waldo, we mean Steve Bazinski.

Since the last update, we’ve been sitting around running simulations or running around looking for people. We completed our Solidworks model (design #2) up to ASTM standard and Dr. Kobus wants us to try running thermal simulations on it to see how much of the heat will travel through our specimen and how much with travel through the sides of our insulated walls. Our problem is that neither of us are experienced enough with Solidworks thermal simulation to set it up properly. We watched a good amount of YouTube videos to try and learn how to do it, but the tutorials are all too basic for our application. We decided that we needed an expert’s help. We contacted Dr. Guessous to see if she could help us with Solidworks or maybe teach us Fluent, but sadly she has been riddled with migraines, so we can only wait until she comes back.

While all of this has been going on, Michael has been online shopping for parts that we need for the hot box apparatus. He found Thermocouple wire, thermocouple connectors, and heat flux sensors. The problem is that heat flux sensors are around $310 and we need about 2-3 of them, putting a strain on our budget. We consulted Dr. Kobus and he told us that Dr. Wang told him that there is a part time professor here who has heat flux sensors that we could potentially borrow. This professor is Steve Bazinski. This began our endless search for him and his heat flux sensors. He has no permanent office and he only teaches class on Mondays and Wednesdays at 5:30pm. Needless to say, we did not find him.

We had a change in personnel recently! Another high schooler was added to our team. Her name is Rachel Lee. She is pictured in the middle of the three above. Nikita is on the right and Amanda is on the left. We also got to meet Dr. Meng Xu who will be working with the RET program alongside us.

BLOG: Entry Number Two

We are getting better at this

Practice makes perfect and two blog entries are probably not enough practice, so bear with us as we learn.

Update!

Since the last entry ended with us anticipating the meeting with the two high schoolers that will be working on this project with us for the next three weeks, we can proudly announce that we have met them and they have been working with us for about a day. Their names are Nikita and Amanda. They have been friends since Junior High and they both run cross country (yikes!). They are quiet and very hardworking!

Progress

Sadly, it would seem like we haven’t gotten much progress done since we are still in the middle of dissecting that 44 page ASTM c1363-11 standard that Michael found. With the help of Nikita and Amanda, it should make things a whole lot quicker. While reading through the standard, we were shocked to find that this apparatus has the potential to be HUGE. The standard is hard to read and a lot of its constraints aren’t very clear or aren’t logical the way we interpreted them. With the way things are currently going, we suspect that it’ll take us a few more days until we can get a grasp of what this standard really wants.

First blog post

Introduction

So…..this is a blog that we are required to make for our project….. we don’t know if it’s evident or not, but we definitely have no experience writing blogs. Being the engineers that we are, we are going to treat this like a lab report, so for any who are interested, keep reading. We promise to make it extra boring.

Premise

So the project that we are working on for this Automotive and Energy Research Program (funded by the NSF) is called (insert official name that we’ve yet to make up). Basically we will be designing an ASTM c1363-11 standard testing apparatus that will measure the heat loss and change in temperature from one side of a panel of material to the other. Using the values that we obtain, we can then calculate (using smarty party heat transfer knowledge) the thermal resistance and R-value of said material. Repeating the same process with a variety of materials, we will be able to compare the thermal properties of each material and determine the efficiency of their use.

What Materials?

We’re not sure yet… We’ve been told that we may be working with a new ceramic foam and some type of concrete with aerogel (solid smoke) mixed in. They will mainly be thermal-insulating materials.

Motivation

Our project will determine the different thermal properties of new composite materials. This will enable us to compare the new materials with the existing ones to see if they would serve better as thermal insulation, while still being structurally sound, than what is universally accepted and used. For example, buildings today are made out of concrete. Concrete, while very strong and stable, has a low thermal resistivity. This creates a problem when a fire occurs, as heat can easily transfer through the walls and ignite material on the other side of the walls, allowing the fire to spread. One of the materials that can be a possible solution to this problem is a concrete-aerogel composite, which would have the strength of the concrete while having the thermal resistivity of the aerogel. The problem is that there is no existing thermal data for this material. Our job is to find the thermal properties of materials like this to determine its ability to be applied in different areas.

Who all is Involved?

Our advisers are Dr. David Schall and Dr. Chris Kobus.

Our sponsor is Fred Deans from Allied Composite Technologies LLC.

We were told in our last meeting that we will be working with two high-achieving high school students as well as two middle school or high school teachers that are a part of the RET program here on campus.

Our Current Progress

Well considering that we were assigned this project less than a week ago, plus last weekend was memorial weekend, we don’t have much.

The end of last week was spent brushing up on our heat transfer skills since Michael had never taken Heat Transfer and Leanna has only taken introductory Heat Transfer and that was awhile ago (almost 2 years!). Dr. Kobus gave us like 20 hours of lecture videos to watch (which by the way is only 14 hours if you speed him up by 1.5x). We had some homework to do which helped us solidify the concepts we learned about. Then we had a meeting with Fred Deans from Allied Composite Technologies LLC to talk about what they are expecting from us and what we are expecting from them. Today’s we’ve been looking up the ASTM c1363-11 standard on how to build a hotbox. Michael found the $71 document for free on the University of Alabama’s database (Thanks Alabama!). Dr. Kobus told us that the high school students will be ready to roll at 2:30pm and that we are supposed to give them a crash course on Heat Transfer. So while Michael was reading up on hot box requirements, Leanna made some lecture notes so that we’d be prepared when they come.