anyone started on this lab? because i got a question. in the lab they say to use a tabulated k for armco iron to find Q_ref, so is the k_tab the same as k_exp for armco iron?

3/16/2006 12:39:43 PM

yes it has to be

3/16/2006 1:46:54 PM

i thought it was Delta T of the iron/2
what is the radius of the rod?

3/16/2006 2:14:03 PM

ok, thanks.

also, if you get to step 5 to calculate Ts1,i and Ts2,i, the equation doesn't make any sense to me because temperatures that comes out doesn't correspond with the TC's. like when i did it with copper, Ts1 was less than TC1 even though it's closer to the boiling water. is this a typo?

^ the diameter, which is constant through out, is given in the hand-out. d = 0.0254m

3/16/2006 2:19:41 PM

for my copper, my Ts1 is greater than TC1. albeit, not by much, but it still is greater. i would check ur math and signs to make sure everythin is right.

3/16/2006 2:36:05 PM

yeah i'm wrong about the k is its the tab

3/16/2006 2:41:45 PM

yeah, my signs are off. one more negative than i need.

3/16/2006 2:47:14 PM

i guess i was not definitely listening in class and thought that the hand-out would tell me, but what two curves are we suppose to plot on the temp vs. distance diagram?

[Edited on March 16, 2006 at 8:33 PM. Reason : lol i suck]

3/16/2006 8:32:46 PM

What am I doing wrong? I am getting exactly the same exp and therotically k value for all materials.


I interpolated to find the kexp for all materials then used that value to find Qref and kexp.

[Edited on March 18, 2006 at 7:17 PM. Reason : .]

3/18/2006 7:11:21 PM

yeah wtf

I still don't understand if kexp is supposed to be the same as ktab. The equation for kexp is just the Qref equation solved for k. So kexp comes out to be exactly the same as ktab.

For the plot, you have to figure out the distance x from the top of the rod for each TC. TC11 and TC12 don't go on there because they are not part of the rod. To find x, use the diagram given in the lab that has the rod and all the measurements. Then make a plot where T is the TC and x is the corresponding distance from the top.

3/19/2006 4:48:43 PM

Do we just use the k(tab) for iron for all materials?

Secondly what is Tmi and Tm+1?

3/19/2006 5:47:35 PM

how does one find R

3/19/2006 6:21:23 PM

bttt

3/20/2006 2:47:28 PM

What are yall getting for Qref. I got 5.44 and my kexp is pretty close to ktab for steel and aluminum but its way off for copper and brass. My Qnet is way bigger than Qref too.

[Edited on March 20, 2006 at 9:08 PM. Reason : ]

3/20/2006 9:03:38 PM

i got 21.24

3/20/2006 9:23:10 PM

Big:

I got the 5.somethin too, but my Q net was also dead on even tho my k's did the same thing yours did. The k's differ as you get farther from the reference k

3/20/2006 9:33:11 PM

i cant get my Qref=5.9 and Qnet=4.9 to line up either, im off by 1. ive checked my calcs and they are good. for part2 my L(delta x)=30mm. part 3 my delta x(L)=30mm. Lj=35mm and Li=40mm. dont know where else i couldve made a mistake.

3/20/2006 11:28:44 PM

On the wind tunnel measurments...as the dynamic pressure increases is the velocity suppose to decrease because that is what is happening with mine.

3/26/2006 6:28:00 PM

no it's not. check all ur units and calculations.

3/26/2006 6:56:38 PM

I believe i'm messing up on my delta pressure. I have to convert in.ofHg into lbf/ft^2...now does delta P=that minus the dynamic pressure?

3/26/2006 7:32:55 PM

or is Delta P just the dynamic pressure

3/26/2006 10:47:21 PM

The hand out says that you measure delta P, so I think that it is just the dynamic pressure.

3/26/2006 11:19:59 PM

My data is fucked, anybody in sec 207, my numbers are jumpin up and down making an ugly graph.

3/28/2006 5:27:41 PM