Performance Trends EZ Flow System. - What's your opinion?

[Greg]

Has anyone had anything to do with the ? I know their software is good stuff as Superflow resell it for their benches.

Can anyone tell me more about a streamlined orifice, I like the idea of not having to change orifices as the flow rate rises but what do you lose (if anything) in accuracy? From the look of the thing it isn't a laminar flow element like the Meriam units.

Is this the same type of setup that Audie use in their Quik Flow system?

They also make some other pretty cool looking flowbench addons which might be worth a look.

[84-1074663779]

In my experience you need to be very careful about putting anything upstream of an orifice as it will effect the flow coefficient.

Ideally, the upsteam air needs to be a large volume of still undisturbed air, and the flow through a thin sharp edged orifice is pretty predictable if the pressure drop across the orifice is made reasonably high.

As soon as you have turbulent up stream air, and run a low pressure drop orifice, the flow coefficient can vary in unpredictable ways. Sure, you can calibrate it, but if you make changes anywhere in the system, repeatability is not going to be good.

The best way to build an orifice type bench is to have the test hole in the top of the bench leading into a large volume plenum space. The orifice should be well away and out of direct line with the test hole. It should also be located on a flat surface away from any nearby walls by a few diameters, so air can flow evenly towards the orifice from every direction.

The higher the planned pressure drop across your measurement orifice, the less any slight upstream turbulence is going to effect the flow coefficient. The only disadvantage is the greatly increased blower power required to do this.

If you do it right, you should be able to measure identical pressure drops across the measurement orifice, and a second identical orifice taped flat over the test hole.

The beauty of doing it this way is that the flow numbers will agree very closely with the orifice formula, and all your orifice hole sizes will behave in proportion as expected.

Fitting an orifice into a pipe with upstream bends and so on, will work, but you will need to test and calibrate every individual orifice. Also, the sizes will not be even steps because as flow increases with increasing hole sizes, things will become more hairy and unpredictable.

Concentrate on getting your largest orifice to work properly at the highest flow. It is always the most difficult. The next hole size down will work even better as flow turbulence will be less.

[pablo]

Audie stuff is used by the best Nextel Cup (Nascar) engine builders. Their motor controller makes alot since. Their Flowbench products are very cool and not that spendy!!

[SWB]

The Flow Quik is an annubar (averaging pitot tube) setup similar to Bruce's bench. It just has the fancy magic box to calculate the flow volume and make the corrections to a standard depression.

I've read about radius entry orifices in fluid dynamics books and I don't think from what I've read that there is any real advantage to using one. The upstream static port has to be something like 6 diameters from the leading edge of the radius and the downstream pickup is right at the edge of the orifice like on a standard setup. From what I know, the radiused orifice has to be used inside a run of tubing and can not be used at the side of a plenum like a standard orifice as mentioned above. But I could be wrong!

SWB

[Shawn L]

I was reading somewhere(can't remember yet) that the orifice needs to be X amount of diameters down stream and y diameters upstream of any disturbance in the pipe diameter it resides in.
Has anyone come across info stating that this is not the case and reasons why?