HVAC problem 1

[falcon1654]

I am involved in designing a very small hvac system with a Blower Fan at 700 CFM 2inwg. I can not find a sutible equation that will give me the preassure losses for the following:

A 700 CFM supply entering a 15" diameter cone diverging to a 8" diameter circular duct. The cone is 17" long with an angle of 10 degs.

B. A circular spilter duct to split the 700 cfm to 350 cfm to different directions.
If anyone have any Ideas Falcon1654 would appreciate it.

 

[quark]

The loss coefficient in your case for the area ratio of 3.51 (=15*15/8*8) with 10⁰ taper is about 2.56. The velocity at inlet condition is about 570 fpm. Now calculate velocity pressure at inlet condition and multiply it with the loss coefficient. This gives you pressure loss at the section.

Refer to ASHRAE duct fitting database or SMACNA manual for other data.