### Pressure drop in a compressed air system (assignement)

Posted:

**Thu Sep 19, 2019 7:55 am**Good day all, i need help to solve some points of this exercice!

The candiate has to size the loop ring pipe and primary air receiver AS1 in a compressed air system given that

• Standard conditions

• Compression ratio 7

• Max pressure drop in the loop 0.1 bar

The first part has been solved

My problem come after calculating the pressure drop using the following formula

where:

Dp = pressure drop (bar)

QC = Air demand (m3/s of free air)

L = length (m)

d = internal diameter (mm)

p = pressure (bar) (abs)

the compression ratio is 7 so In my case P=7 bar

This table displays the results of the professor

I can’t find the same value of the pressure drop in branch 1 and 3 (colored in yellow)

Any help would be highly appreciated!

The candiate has to size the loop ring pipe and primary air receiver AS1 in a compressed air system given that

• Standard conditions

• Compression ratio 7

• Max pressure drop in the loop 0.1 bar

The first part has been solved

My problem come after calculating the pressure drop using the following formula

*dP= 1,6*10^8*[(L*Qc^1,85)/(P*d^5)]*where:

Dp = pressure drop (bar)

QC = Air demand (m3/s of free air)

L = length (m)

d = internal diameter (mm)

p = pressure (bar) (abs)

the compression ratio is 7 so In my case P=7 bar

This table displays the results of the professor

I can’t find the same value of the pressure drop in branch 1 and 3 (colored in yellow)

Any help would be highly appreciated!