Previous in Forum: Tea Bag Machines   Next in Forum: NPT male thread pressure ratings
Close

Comments Format:






Change Mode
Close

Subscribe to Discussion:

CR4 allows you to "subscribe" to a discussion
so that you can be notified of new comments to
the discussion via email.

Close

Rating Vote:







Add Vote
18 comments
Rate Comments: Nested
nathaniel1105
Associate

Join Date: Jan 2009
Location: Houston, TX
Posts: 54

Wind Tunnel Pressure Drop

03/20/2009 10:32 AM

I am currently designing a wind tunnel to test the pressure drop through a box with several slopes and turns. I will drill a hole on the inlet and outlet bottom of the wind tunnel, just outside the box, so that I can place a transversing pitot tube on both sides. I will measure the pressure distribution on both sides so that I can obtain an accurate solution to the pressure drop. I have tried Google, and I couldn't find an answer to this - how do I set-up the system of transducer(s), pitot tubes, Scope VI, etc. to measure this? Before, when taking data, I used to just use the system that was already in place. However, I am building one from scratch and do not have access to the previous system. If there is a website, you can direct me there. Thank you in advance for your response.
Register to Reply
Pathfinder Tags: pitot tube pressure drop transducer wind tunnel
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.
rakesh_semwal
Guru
India - Member - New Member Engineering Fields - Electromechanical Engineering - New Member

Join Date: Oct 2006
Location: India, 200 Km. North of Delhi.
Posts: 1393
Good Answers: 53
#1

Re: Wind Tunnel Pressure Drop

03/20/2009 10:53 AM

I guess you are from USA, AMCA 108 should be easily accessible to you.

go here

http://www.amca.org/
Register to Reply
nathaniel1105
Associate

Join Date: Jan 2009
Location: Houston, TX
Posts: 54
#2
In reply to #1

Re: Wind Tunnel Pressure Drop

03/20/2009 11:13 AM

This is an interesting association; thanks. However, I am looking for an experimental set-up, not a standard. I want to know how I can hook up my pitot tube and transducer(s) (and any other equipment I might need) to obtain the readings on a computer.
Register to Reply
PWSlack
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on.
Posts: 32175
Good Answers: 839
#3
In reply to #2

Re: Wind Tunnel Pressure Drop

03/20/2009 11:47 AM

OK, so the transducer will have some sort of output, and the computer will have some sort of input. They just need to be the same.

What's the transducer output, then?

__________________
 "Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply
nathaniel1105
Associate

Join Date: Jan 2009
Location: Houston, TX
Posts: 54
#6
In reply to #3

Re: Wind Tunnel Pressure Drop

03/20/2009 2:10 PM

It will be a voltage output.
Register to Reply
user-deleted-1105
Guru
Popular Science - Weaponology - New Member United Kingdom - Member - New Member

Join Date: May 2007
Location: Harlow England
Posts: 16512
Good Answers: 670
#9
In reply to #6

Re: Wind Tunnel Pressure Drop

03/20/2009 2:47 PM

this post is intentionally blank

__________________
 health warning: These posts may contain traces of nut.
Register to Reply
nathaniel1105
Associate

Join Date: Jan 2009
Location: Houston, TX
Posts: 54
#10
In reply to #9

Re: Wind Tunnel Pressure Drop

03/20/2009 2:49 PM

My point being that my output is voltage - a response to a previous question.
Register to Reply
user-deleted-1105
Guru
Popular Science - Weaponology - New Member United Kingdom - Member - New Member

Join Date: May 2007
Location: Harlow England
Posts: 16512
Good Answers: 670
#11
In reply to #10

Re: Wind Tunnel Pressure Drop

03/20/2009 2:50 PM

Yeah, I know..I miss-read the posts,, I am just a cat.. my bad....and hence the hasty edit

__________________
 health warning: These posts may contain traces of nut.
Register to Reply Off Topic (Score 5)
nathaniel1105
Associate

Join Date: Jan 2009
Location: Houston, TX
Posts: 54
#12
In reply to #9

Re: Wind Tunnel Pressure Drop

03/20/2009 2:54 PM

lol. I see the traces of nut.
Register to Reply Off Topic (Score 5)
DVader1000
Guru
Engineering Fields - Environmental Engineering - New Member APIX Pilot Plant Design Project - Member - New Member

Join Date: May 2007
Location: Anywhere Emperor Palpatine assigns me
Posts: 2774
Good Answers: 101
#4

Re: Wind Tunnel Pressure Drop

03/20/2009 11:51 AM

Does this help? http://en.wikipedia.org/wiki/Wind_tunnel

__________________
 If only you knew the power of the Dark Side of the Force
Register to Reply
nathaniel1105
Associate

Join Date: Jan 2009
Location: Houston, TX
Posts: 54
#7
In reply to #4

Re: Wind Tunnel Pressure Drop

03/20/2009 2:13 PM

Thank you. However, I am looking into connecting the wind tunnel - I already have it made. I just need to work on electrical.
Register to Reply
user-deleted-1105
Guru
Popular Science - Weaponology - New Member United Kingdom - Member - New Member

Join Date: May 2007
Location: Harlow England
Posts: 16512
Good Answers: 670
#5

Re: Wind Tunnel Pressure Drop

03/20/2009 1:44 PM

With two monitoring points just connect them to eitherside of a differential pressure transducer.
Something like this push on pvc tube will probably suffice at the pressures you are likely to encounter.
Del

__________________
 health warning: These posts may contain traces of nut.
Register to Reply
nathaniel1105
Associate

Join Date: Jan 2009
Location: Houston, TX
Posts: 54
#8
In reply to #5

Re: Wind Tunnel Pressure Drop

03/20/2009 2:17 PM

Interesting. This would be a lot easier than switching between pitot tube ports. Now, I can essentially take the measurements at the same time, and find the pressure difference. I will only be dealing with about 5 in. H20, so this could definitely work
Register to Reply
Anonymous Poster
#13

Re: Wind Tunnel Pressure Drop

04/02/2009 2:47 PM

hey nathaniel, i am also working on a wind tunnel. what university are you attending? i am also in houston, tx.
Register to Reply
nathaniel1105
Associate

Join Date: Jan 2009
Location: Houston, TX
Posts: 54
#14
In reply to #13

Re: Wind Tunnel Pressure Drop

04/06/2009 10:40 AM

University of Houston. You?
Register to Reply Off Topic (Score 5)
Anonymous Poster
#15
In reply to #14

Re: Wind Tunnel Pressure Drop

04/30/2009 12:43 PM

here at UH as well. we are designing and constructing a 15"X15"X24" wind tunnel. total about 12 ft in length. Need some help calculating the theoretical pressure drop at the entrance cone, test section and diffuser. Wind speed up to 60 mph.
Register to Reply Off Topic (Score 5)
nathaniel1105
Associate

Join Date: Jan 2009
Location: Houston, TX
Posts: 54
#16
In reply to #15

Re: Wind Tunnel Pressure Drop

04/30/2009 1:33 PM

Really at UH? Interesting. That's some good wind speed. Wish I could've used your fan for the experiment. Where are you set-up?

Anyway, we didn't do any theoretical calculations, so I am a little unsure of how to do that. If you gave me dimensions of entrance cone, test section, diffuser, etc. I might be able to help you out. If the test section is some weird geometry (i.e. box full of weird slots and dimensions), then that is really out of my scope and expertise. That would require a computational program that could only be determined with experimental data.
Register to Reply Off Topic (Score 5)
Anonymous Poster
#17
In reply to #16

Re: Wind Tunnel Pressure Drop

05/01/2009 11:17 PM

Yeah, here at the technology college. We are designing and building a wind tunnel for the fluids lab over the summer. I was trying to use Burnelli's equation of conservation but it gave me this weird pressure drop in the test section. test section: 15"hx15"wx24" l Contraction cone: 45"x45" inlet 15"x15" outlet, length - 30" diffuser: 5 degree angle, 30" diameter outlet, 15x15" inlet, 84" length. The test section is considered simple as of now, until we test for % turbelance we might add some slots of sorts to straighten the flow if we need too, but not for the calculations. what was your tunnel like?
Register to Reply Off Topic (Score 5)
nathaniel1105
Associate

Join Date: Jan 2009
Location: Houston, TX
Posts: 54
#18
In reply to #17

Re: Wind Tunnel Pressure Drop

05/05/2009 9:34 AM

Your wind tunnel definitely has a lot more ingenuity than ours. We just built two 2'x2'x4' sections that sandwiched a lateral flow reactor (just a fancy filter). We used PVC pipes at inlet to get rid of flow separation in the entry. If you want, you can email me your calculations and I could check them out to see if I catch any mistakes. It always helps to have another set of eyes. nathaniel.jolliff@gmail.com

I am not the best expert, but it seems you have enough tunnel length for the flow to be straight. What is the wind speed?
Register to Reply Off Topic (Score 5)
Register to Reply
Have a Different Question?
18 comments
Copy to Clipboard

Users who posted comments:

Anonymous Poster (3); DVader1000 (1); nathaniel1105 (9); PWSlack (1); rakesh_semwal (1); user-deleted-1105 (3)

Previous in Forum: Tea Bag Machines   Next in Forum: NPT male thread pressure ratings
You might be interested in: Wind Tunnel Testing Services, Tunnel Diodes

Advertisement

Got Something to Say?
Ask a Question
Start a Discussion

Search this Forum
Mechanical Engineering:
Go

CR4 Sections
Aerospace
BioMech & BioMed
Chemical & Material Science
Civil Engineering
Communications & Electronics
Education and Engineering Careers
Electrical Engineering
General Discussion
Instrumentation
Manufacturing
Mechanical Engineering
New Technologies & Research
Software & Programming
Sustainable Engineering
Transportation

Site Directories
Forum Directory
Blog Directory
User Group Directory
RSS Feeds

CR4 Rules of Conduct
CR4 FAQ
Site Glossary

Who's Online (120 right now)
Show Members
Advertisement