Haybusa Parts and Service Member Support

Author Topic: air flow and volume question  (Read 6919 times)

Offline len

  • Post Master
  • *****
  • Posts: 1298
air flow and volume question
« on: October 31, 2002, 01:18:00 PM »
Ok here it is, if you take a pipe 2inchs inside dia. and 3 ft long with one 90 deg. bend . how much air can flow thru in Cubic feet per minute at 6psi. and likewise the same question  for two pipes combined, both 1 and 1/2 inches in dia.. The bends are not reduced in ID but relativly sharp.Anyone? thanks, DODO
MY MOMMA TOLD ME I WAS SLOW!!! What did she mean ?

Offline BiggerDanno

  • OFF TOPIC
  • Mad Post Whore
  • **********
  • Posts: 4146
  • HOW FAST IS FAST?
air flow and volume question
« Reply #1 on: October 31, 2002, 01:31:00 PM »
It depends on velocity of air and weight of air, both of which vary with temperature.

In ballpark figures (discounting all variables), one 90 degreee bend in a 2" pipe adds the equivilant of 5.5 ft. of pipe worth of restriction.

For 1" pipe, it is 2.6 ft.
For 1.5", it is 4.0 ft.
A man is not old until regrets take the place of dreams...John Barrymore

Too much power is addictive!!!

Offline len

  • Post Master
  • *****
  • Posts: 1298
air flow and volume question
« Reply #2 on: October 31, 2002, 02:01:00 PM »
OK, Danno thanks , What I need to know is if I supply 6psi at one end of pipe, how many cfms can I flow thru one 2inch or two--1and1/2 pipes. with a endless supply of 6psi at one end.I'm looking for volume in cfms, compairing the 2' to the 1 1/2' .whats the max flow, with standard 29.92 pressure at the discharge end.
MY MOMMA TOLD ME I WAS SLOW!!! What did she mean ?

Offline len

  • Post Master
  • *****
  • Posts: 1298
air flow and volume question
« Reply #3 on: October 31, 2002, 02:51:00 PM »
come on, I know their are some smart sons of beaches on here. please answer this for me.  
MY MOMMA TOLD ME I WAS SLOW!!! What did she mean ?

Offline BiggerDanno

  • OFF TOPIC
  • Mad Post Whore
  • **********
  • Posts: 4146
  • HOW FAST IS FAST?
air flow and volume question
« Reply #4 on: October 31, 2002, 03:01:00 PM »
quote:
Originally posted by dodobird:
OK, Danno thanks , What I need to know is if I supply 6psi at one end of pipe, how many cfms can I flow thru one 2inch or two--1and1/2 pipes. with a endless supply of 6psi at one end.I'm looking for volume in cfms, compairing the 2' to the 1 1/2' .whats the max flow, with standard 29.92 pressure at the discharge end.

Still, not enough info.
Need the air temp & humidity. They both affect velocity, which has a direct impact on max cfm.

Gimmee some time to figure out how to properly show the formula in this format, and I can give it to you to figure out.
A man is not old until regrets take the place of dreams...John Barrymore

Too much power is addictive!!!

Offline BusaGeek

  • Post Whore
  • ****
  • Posts: 586
air flow and volume question
« Reply #5 on: October 31, 2002, 04:12:00 PM »
What kind of pipe.  The material will have a huge effect on the outcome.

Offline len

  • Post Master
  • *****
  • Posts: 1298
air flow and volume question
« Reply #6 on: October 31, 2002, 04:18:00 PM »
thanks, danno, you could use , say 100deg. temp And density, I would think would be combination of air pressure,temp, and speed, humidity,. but any way, I'm contemplating using two air induction tubes from the blower to the intake ports, 1 1/2" dia. instead of one 2 1/8" dia. and am tring to find out if I can flow enough volume. two slightly smaller tubes might not flow as much as a single larger one. sometimes everythings not as straight forward as it looks. I know I can probibly increase the pressue to get the volume, but I really dont want to, but their are alot of things I can take advantage of using two smaller tubes instead of one larger.Let me know what you come up with,.  
MY MOMMA TOLD ME I WAS SLOW!!! What did she mean ?

Offline BusaGeek

  • Post Whore
  • ****
  • Posts: 586
air flow and volume question
« Reply #7 on: October 31, 2002, 04:22:00 PM »
I think this number is going to be huge.  From http://www.aquatext.com/tables/frict-air.htm for 2 inch pipe at 250cfm, you will lose 2.44psi in 100 feet with PVC pipe.  In 6 feet that would make about 0.14psi.

Assuming that pressure loss varies with the square of flow (it seems to from the chart), that would put your answer at about 1500cfm!!!

THEMOTORHEAD

  • Guest
air flow and volume question
« Reply #8 on: October 31, 2002, 04:34:00 PM »
GOOD FIND THERE GEEK

Offline len

  • Post Master
  • *****
  • Posts: 1298
air flow and volume question
« Reply #9 on: October 31, 2002, 05:00:00 PM »
So, looks like at 200cfms in 11/2inch pipe aprox 5 ft it would be .28 psi loss, and if the pipe is doubled, as in two, it would cut that in half to .14 psi loss. is that what you get out of it.? thanks geek
MY MOMMA TOLD ME I WAS SLOW!!! What did she mean ?

Offline BusaGeek

  • Post Whore
  • ****
  • Posts: 586
air flow and volume question
« Reply #10 on: October 31, 2002, 05:09:00 PM »
From that chart it looks like doubling the diameter gives around 1/20th of the pressure drop.  So .28psi at 1 1/2 would turn into around 0.01psi at 3 inches.

Offline len

  • Post Master
  • *****
  • Posts: 1298
air flow and volume question
« Reply #11 on: October 31, 2002, 06:23:00 PM »
thanks guys, I think I'm going to try the two 11/2 inch and see what happens. I'll let you know the results
MY MOMMA TOLD ME I WAS SLOW!!! What did she mean ?