Determine the diameter for a round tape suitable for carryin

Determine the diameter for a round tape suitable for carrying 0.40 m^3/ s of air with a maximum pressure drop of 1.00 Pa/m of duct. Total length of the duct is 80m. Select the duct size by rounding up the next 50 mm increment.

Solution

>> As, p= (0.109136 q^1.9) / d_e^5.02   , where

p = friction (head or pressure loss) (inches water gauge/100 ft of duct)

d_e = equivalent duct diameter (inches)

q = air volume flow - (cfm - cubic feet per minute)

>> Now, Q = Volume Flow = 0.40 m³/s = 847.552001 cfm

L = Length = 80 m = 262.467 ft

Presure Drop = 1 Pa/m = 0.3048 Pa/ft

Putting all values in above equation,

=> d = 6.514 inch

or, d = required diameter = 0.16545 m .....ANSWER........