How to measure swirl?

[arnotoekan]

Last week i was visiting a friend and he had a SF600 with a flowcom. The Flowcom could measure the Swirl

I want that function too on my SF300. How can i measure or calculate this?

(I dont have the need to buy a flowcom)

[imgatt]

[Thomas Vaught]

It is obvious that the number is calculated vs actually read. I am familiar with the
flow com hardware know of no other way they could be getting the number
Tom V.

[86rocco]

[bruce]

On my bench I use a small DC motor with 4 straight blades on it, this is connected to a Harbor Freight cheap digital multimeter. Clockwise rotation gives a + and counter clockwise a - voltage output.

I have no way of knowing what the number means other than the higher the voltage the faster the swirl. So long as you use the same setup everytime on your flowbench the "number" really doesn't have to mean anything in flow terms I feel.

In parts my total cost is under $10, but there is sometime to make the blades and motor adaptor.

[Mouse]

Flow Performance is currently investigating a whole new way of very-passivley measuring swirl that will work with all FP1 processors and can be adapted to all cylinder bores. Hope to have some details soon.

[bruce]

I wasn't sure how well my setup would work till I actually sat down and gave it a try, its interesting to watch the meter spin and then you go to the next lift point and wam its starting spin the other way! Wanna talk about generating some numbers! I have been amazed at what actually happens to the flow inside my flatheads. This setup can be fit inside a bore adaptor. Mine is made to slip into my bore adaptor and feeds the wire out through a hole to my meter. The motor was robbed out of an old battery operated tooth brush (not alot of high-tech here in my shop)

[DaveMcLain]

Performance Trends makes a swirl meter that's compatable with the Flow Com, The Perf Trends Black Box and it can also be used as a stand alone device with it's own readout.

[115-1172523331]

[color=#000000]Hi all, Here are some pics of the swirl meter I am building (following Bruce

[115-1172523331]

I know it says 10 images per post, but I can't figure out how toget more than one! Can someone help?

Anyway, here is the test assembly in place! -- Doug

[maxracesoftware]

the old Quadrant Scientific Company
offered a Digital Swirl Meter
it was the HoneyComb Strain Gauge Type

it measured Swirl in Inches/Ounces of Torque

The HoneyComb does not or is not capable of
completely spinning a complete revolution,,
instead its travel is about an inch in either
Clockwise or CounterClockwise direction.

i used a bright yellow paint,
and painted a Radius Line from the Center point
of the HoneyComb -to- the 6:00 O'Clock position.

then by looking at this Yellow Line thru clear plexiglass
you could see visually the Swirl direction and jitter,
and of course see results on Digital Meter as well.

Like an example,
the old SBC #292 Turbo Heads had tremendous Swirl
....4 Cylinders had Clockwise, the other 4 CounterClockwise.

if you want more Swirl...just lay back the Short Turn Curve

[bruce]

[115-1172523331]

Hi Bruce, Thanks for the tip on posting images! I actually used Photobucket for one post here.

I have a few questions about your swirl meter.

Your post was dated 3/06. Do you still use it or was it not useful, other than "gee whiz"?

Was there anything that would have improved the usefulness? I was thinking about calibrating the RPM to the voltage, then could get the "CFM/rev" (if that is any better).

Do you remember about the level of voltage output (.001, 1, ...)?

I was looking at your engine pic. As a flathead, have you ever made a plexiglass head to be able to watch flow?

Doug

PS - Pic shows the assembly in the settling chamber/test fixture. Will add a hold down "mechanism" for the bore adapter before final assembly, probably T-nuts and through bolts.

[bruce]

I have used it but to many numbers and from one lift to the next you could go from clockwise to counter clockwise rotation on my engines.

It is another tool you can use in your testing and I plan on using it again, I keep it in my bore adapter and all I have to do is hookup the meter to it. I don't think it's something you use all the time though. Which I know you realize.

By switching Mv ranges you can change the output. If I recall I saw less than 1 volt? I did not keep any notes as it was just a gee whiz thing at the time. If I ever get a chance to get serious again about my testing program I'll refine my project. I'm interested in how the carbon fiber blades work for you. The heavier alum blades (.062" thick) I used kinda offset the torque required to turn the motor. It is amazing how little airflow is required to make it spin! Again no firm data but it is a cheap toy to have around and you will find it helpful!

I think you will find you really don't need to worry about calibrating it once you have it running. As long as you test your parts and can compare numbers you will get useful data. Higher volts means it's spinning fast, clockwise is + counterclockwise is - have fun testing!

I'll PM you or shoot you an email about the other stuff . . .

[83-1184962233]

I'm watching this thread with interest. Since reading about homemade swirl meters in Bill Jone's porting book I wanted to build one once my bench is built.
Please keep us up to date

[115-1172523331]

Bruce, Thanks for the info, I think I have it right! The paint has dried, the motor has been mounted and I ran a quick test today. Using a variable speed 3/8 drill, I spun the motor to full drill RPM (900 no load, and this is about as close as one can come to no load). My meter shows 0.13 VDC clockwise and a neg 0.13 VDC counterclockwise. Progress, however, has come to a screeching halt. The local (60 miles one way) hobby shop can order my carbon fiber for the blades, but doesn't stock it! There are some things I really like about living in a small town (after 33 years in Los Angeles), but there are others that leave a little to be desired!

All is not lost however. I was not too happy with the geometry corrections required for my variable inclined manometer, so tried a cut and paste on the computer. It looked so easy that I did it for real and the paint (1st coat) is drying on that piece. That writeup will come in the Reader's Flowbench Projects - It's Finally Working post when I can get some new pics. I am also updating the spreadsheet and will post that in the Spreadsheets section after I have tested it.

In an earlier post, Bruce asked for a pic of my zeroing method for the vertical manometer. I have a shot now and have included it here (don't want to waste the "empty" attachment!

Doug