arcenas
Mechanical
- Jun 16, 2010
- 1
Hi! Could somebody help me regarding this?
All of the data on loss coefficients are based on fully developed flow of air into the fittings ( free stream loss coefficient ). Air leaving fan, elbow, tee or any duct fittings is always turbulent and distorted. You actually need a certain length ( 5 to 10 dia in duct lenght ) for the flow to fully develop. If the air flow does not become fully developed the pressure drop of the downstream fittings will generally increased including noise.
I am actually looking for methodology / reference or books that tells you how to calculate or compensate for fittings installed very close to each other. Using the loss coefficent for fully develop flow is inaccurate.
I have tried ASHRAE and It does not tell you about this problem.
Thank you
All of the data on loss coefficients are based on fully developed flow of air into the fittings ( free stream loss coefficient ). Air leaving fan, elbow, tee or any duct fittings is always turbulent and distorted. You actually need a certain length ( 5 to 10 dia in duct lenght ) for the flow to fully develop. If the air flow does not become fully developed the pressure drop of the downstream fittings will generally increased including noise.
I am actually looking for methodology / reference or books that tells you how to calculate or compensate for fittings installed very close to each other. Using the loss coefficent for fully develop flow is inaccurate.
I have tried ASHRAE and It does not tell you about this problem.
Thank you