Static pressure measurement vs venturi effect
Static pressure measurement vs venturi effect
(OP)
Hi
I'm using a differential pressure gage to measure static pressure inside a forced air cooled enclosure. My point of measurement is quite close to the blower and I'm just using plain 4mm ID tubing from the gage.
My concern is venturi effect changing my readings - I can blow across the end of the tube and pull 1" of water. Should I have some kind of baffle on the end of the tube to eliminate any venturi effect?
Thanks,
Jon.
I'm using a differential pressure gage to measure static pressure inside a forced air cooled enclosure. My point of measurement is quite close to the blower and I'm just using plain 4mm ID tubing from the gage.
My concern is venturi effect changing my readings - I can blow across the end of the tube and pull 1" of water. Should I have some kind of baffle on the end of the tube to eliminate any venturi effect?
Thanks,
Jon.





RE: Static pressure measurement vs venturi effect
You may want to find total pressure and subtract velocity pressure to find static pressure. I don't know what you have for instruments.
RE: Static pressure measurement vs venturi effect
It is not uncommon in my experience that you have to measure the static some distance from the discharge in order to get a stable,positive, repeatable reading.
The way we build has a far greater impact on our comfort, energy consumption and IAQ, than any HVAC system we install
RE: Static pressure measurement vs venturi effect
Is there any way to get a reliable static pressure measurement behind the blower? (assuming I have the instrumentation)
RE: Static pressure measurement vs venturi effect
Or get the face velocity into the fan inlet with an aneometer or a velocity grid?
The way we build has a far greater impact on our comfort, energy consumption and IAQ, than any HVAC system we install
RE: Static pressure measurement vs venturi effect
http://www.amca.org/
RE: Static pressure measurement vs venturi effect
I guess I should say I'm trying to improve the airflow (cooling)through some complex equipment and I'm just looking for a repeatable measurement so I can see improvements and be sure I'm within the capability of the blower.
I should also say I've never worked with forced air cooled equipment or airflow measurement before.
RE: Static pressure measurement vs venturi effect
TTFN
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RE: Static pressure measurement vs venturi effect
I'm leaning towards just monitoring the flow entering or leaving the unit from outside rather than trying to measure pressure inside, but I still need to find the best way to do this.
RE: Static pressure measurement vs venturi effect
TTFN
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RE: Static pressure measurement vs venturi effect
SMACNA or the Air Balance Council have good guides for flow measurement.
RE: Static pressure measurement vs venturi effect
The way we build has a far greater impact on our comfort, energy consumption and IAQ, than any HVAC system we install