venturi nozzle instead of sharp edged orifice

[Hans Derbe]

Hello,

does anyone here have ever used a venturi nozzle to measure flow in a flowbench? I'm thinking of a symmetrical design that could be used for intake and exhaust when used with a roots blower and vfd to reverse the flow. the extra space needed by this design an the limitation to one size wouldn't be a problem for me. Anything else to consider?

[jfholm]

I have a friend with a venturi bench. I works very well but he is a little limited due to number of motors. With a Venturi bench you can have multiple flow ranges with a single venturi just by the placement of the pressure taps on the opening big side of the venturi. I will go into it further when I get home from work.

John

[jfholm]

Below are a couple of pictures that may help you visualize how a venturi bench would be set up. My friends bench only flows one direction and you can probably visualize why. To flow the exhaust ports you have to have an adapter that bolts to the exhaust port and you tip the head to set on the opening on the flow bench and suck through the exhaust port. this makes it a little tough to probe velocity in the exhaust ports.

John

venturifixed1.JPG

venturi bench.JPG

[jfholm]

Here is a venturi calculator web site if you decide to go that route
http://www.flowmeterdirectory.com/flowm ... _calc.html

John

[SWR]

Hmm.. 3 different venturi sizes.... swapping them by use of big Wiggins clamps either end... literally seconds to swap, much less pressure loss than a orifice bench. I think I'll test that sometime...