How to measure swirl?

[bruce]

Doug, did you get my PM?

[115-1172523331]

Hi Bruce, Yes, I got the PM. Thanks for that info. I understand your problem! I have one much like it myself.

Doug

[115-1172523331]

Hi all, As I slowly progress on my swirl meter, I have been thinking about the output "units". In Ed's (86rocco) post, the units were CFM/rev. Something wasn't "right" about it and tonight I figured it out. Assuming your meter was reading 5600, as shown, and you were flowing 280CFM. Dividing the 280 by 5600 you get .05, but .05 what? The units would be CFM/(CFM/rev) or REV! This has to be the output of the non-spinning torque reaction type of gauge, .05 rev or 18 deg of twist. If you were spinning something, it would be CFM / RPM or CF/REV as output NOT CFM/REV. Assuming 280 and 20rpm (?), you would get 14 CF/Rev (or .0714 REV/CF). Not that it tells us anything, but at least a better (?) understanding.

On the swirl meter front, I broke the tabs off the toothbrush motor and had to get a new motor. While I was at it, I found a source for electronic "goodies" which had a bunch of different motors. Trying to minimize the interference of the motor in the flowpath, I am looking at the one in the attached pic (but bought 7 different ones to play with). There was another smaller than a dime too. These are used as vibrators on cell phones! Some have the eccentric weight still attached, any ideas on removing them. At less than $2.00, they are cheaper than toothbrushes! Some (more expensive) models had encoders as part of the package. If I understand any of this, that means they could output RPM (in some format). I asked Ed earlier, is there an equivalent to "DAQ for Dummies" that someone (me - ) could start with about this subject. I jumped in twice so far and drowned both times! I'll run some MECHANICAL tests on these motors and report back. -- Doug

[DWC]

Hi all,
Im a new member and this is my first post on this forum or any for that matter. Found this forum 2 weeks ago and have enjoyed reading all the info. Anyway about a week ago read Bruces post on using a small dc motor out of a toothbrush to generate a small but measurable current once set up with a paddle wheel and suspended in say a bore adapter. Well that was the key to it for me as i had been thinking of making some kind of swirl meter for a while. I started on it straight away and my 9 year old son was wanting to know where his electric tooth brush was the next morning. I told him it went to a good cause to further dads knowledge of the internal combustion engine. I will try to attach a pic and see what you guys think. Works a treat.

[115-1172523331]

DWC, Nice looking "swirler". It looks to be about a 5 inch hole.(?). Does it sit as is or inverted from the pic and what are you doing for an output meter? What kind of flow numbers do you get and what are the output numbers from the swirl meter? More details! More pics.

I'm having problems fabricating a proper hub for the multi-blade setup. Should have mine running in a couple of days.

Doug

[bruce]

I agree, looks great!

[DWC]

Thanks Fellas,
Ok the hole is 4.250" which is the same as the bottom diameter of the stepped superflow head adapter ( top dia is 4.000" ) the unit sits the same way up as the first picture underneath head adapter and the paddle is situated completly up inside the bore of the adapter. I have just been using a multi meter for voltage readings and that is what the terminals on the side are for the multimeters probes. Doug u say your having trouble with making a hub i didnt bother with a hub just drilled the 0.040" thick aluminium paddle with a number drill for a light press fit on the motor shaft ( 0.8mm dia ) and epoxyed it in place. I must add that i reinforced the paddle where the hole is drilled with some small lengths of the same material and riveted and epoxyed them in place. Just trying to keep the mass down on the paddle to increase its sensitivity.Also i guess thats why i didnt go with a multi blade paddle. Must admit if i say cough on it it sends it spinning alot faster than i would have expected. I will see if i can get some numbers with flow and voltage readings in the next couple of days i will use a chrysler 318 V8 head to do this as i wanted some flow numbers from that head anyway. Will add another pic looking from underneath the unit.
regards.
Darrin.

[bruce]

Darrin, thanks for posting the extra pic! It really is amazing just how sensitive a simple setup like this can be.

[106-1194218389]

Great looking swirl meter. This could either be used with a volt meter like Bruce did or I think you could use it with that inexpensive data acquisition unit that was posted in the forum. I must compliment you guys on the forum as it has saved me literally thousands of dollars.

[115-1172523331]

Hi Darrin, I got my problem figured out and produced a hub yesterday. It's 7/16 inch dowel with a number drill for the shaft and slots cut every 45* on the other end. I want to test with 2, 4, and 8 blades to see if it makes much difference. I'll post the results to save other people who want to try this the trouble. The attached photo(s) show the bottom of the test rig (centered on the page) with the 8 bladed "fan". At the bottom on either side are pics of the 4 blade and 8 blade alone. The micro motor I also want to test (1 of 4) is shown next to the 8. The toothbrush motor is 1/2 D X 1 L. This one is 1/4 D X 1/2 L. Tiny little shaft may be a limiting factor! Upper left is the test setup with my clear, flow viz bore adapter. I fabbed a radiused inlet plate (visible in the setup pic) and a "swirler" (shown on upper right). This is a piece of AL sheet which fits inside the bore adapter and is twisted about 30* to create a uniform swirl for my testing.

I assembled everything to check it out and fired up the bench. I haven't crunched the numbers yet, but with a full 2 inch opening on the bore adapter, I could only pull 4.9 cm depression, but that was over 3 inches rise on my inclined manometer (set at 5 inches max). This is about 108CFM actual or 95CFM corrected. The volt meter was reading between 1.16 and 1.32 volts with the about 1.27 showing most often. I put Bruce's 100 CFM@28 in depression calibration plate over the 2 in bore and the depression climbed to 24.8 cm (almost 10 inches) and the inclined read 44.3 cm so flow was approx 97 CFM actual or 85 corrected. The volt meter was down to .44 volts for this run. I could tell there were leaks (or potential for leaks!) and the motor seemed to stick, then break free and spin up so have to figure that out.

The difference in spin (voltage) seems like it is too much at 60+% given the closeness of flow rates (~10%). Anyone have any ideas? Does the depression level affect this? Hmmm! More to learn again! -- Doug

[86rocco1]

Darrin, that looks great, a nice clean, simple and elegant design. Have you had much oportunity to test it out? If so, how is it for repeatability?

[bruce]

I can't take credit for the swirl meter design, it was discussed on the old forum a few years ago.

[DWC]

Hi all,
Have finally got some flow numbers and voltage readings from my swirl meter to post sorry about the delay been busy with other peoples projects as usual.
Chrysler V8 318 cylinder head (casting #2843675)

v/lift percentage range flow/cfm swirl mv
0.050 54 3 16 250
0.100 83.5 4 33 0
0.150 85 5 50 0
0.200 80 6 67 0
0.250 78 7 82 0
0.300 89 7 93 260
0.350 73.5 8 103 400
0.400 70 8 98 600
0.450 70 8 98 720
0.500 70.5 8 99 800

*cylinder 1 intake flow test performed on superflow 110 bench @ 10"h2o
*0.375" radius entry with 4" bore adapter
*valve dia 1.78"
The readings on the meter were typicaly fluctuating about 50mv as above readings are an average. A point of interest was that without the radiused entry the swirl readings at the lower lifts were eratic and the readings that are zero on the above chart were not and overall mv readings were measurably higher. All readings were quite repeatable as i retested the lift points many times. Will attach another photo of everything set up.
regards,
Darrin.

[MMack]

I am already looking for a small motor and parts to put one together myself, this is really cool stuff.

One thing the Engineer in me as well as the Six Sigma Black Belt is screaming for is what are we shooting for? Is more better, is less better, how much more, or less. How do I calibrate my metric to someone elses to get a point for comparison? When my company started training us on Six Sigma, the slogan was questions lead, answers follow. Once we got to work we found that questions lead to more questions! The deeper you dig the more places to dig you find!!! But you find answers too.

Mike

[WPH]

Many of you might have seen this: