Week Eight Update

Radiator Fin Attachment

To attach the fins, first the surfaces of the pipe and each fin had to be prepared. Both the pipe and the fin surface were cleaned with scotch brite and methanol to remove any oil or impurities. The surface of the copper pipe was also roughened to give the epoxy more surface area to adhere to. The bases of the fins were first coated with thermal paste, then, they were held into place and secured by rubber bands. Once this was complete, epoxy was applied to the two edges of each fin. Once the epoxy for one fin had set, the next fin was begun. It was discovered that a slight bend in the middle of the bonding surface of each fin created a better fit to the rounded surface of the pipe. The rubber bands were removed after 24 hours once the epoxy had fully cured.

Figure 1: Top isometric view of the fins

Figure 2: Isometric view of the fins

Figure 3: Side view of the fins

The goal for week 8 was to get the pipe completely sealed. During the lab, the group brought the pipe over to the machine shop and got it tightened. There was, however, a little miscommunication in the group and so the pipe was only tightened but the PTFE tape was not replaced. The pipe was then tested without having the PTFE replaced and the following is the result from the test.

Test number 3

The pipe was tested again and the figure below plot out the data recorded. The difference here is that there are fins attached to the condenser end. The figures ( 4 and 5) below show the set up and the plotted result.

Figure 4: Set up to test the heat pipe

Figure 5: Result of test 3

The result, however, does not seem to be much different than the result from week 7. The condenser also barely increased in temperature. Not surprisingly, the pipe was also leaking at the time of testing (figure 6 bellow). The team did not do a good job of securing the pipe and so the reason as to why the pipe does not work is still a mystery and the group cannot move on until the pipe has been secure tightly. The leak, however, did seem to be less than that of week 7. If the group could add more layers of PTFE and tighten the cap more then maybe the cap will be secure and result might change.

Figure 6: Leakage of the pipe.