Reducing Tee Loss Factors

[Kennez]

Does anyone know how to calculate loss factors for reducing tees in pipes. I have searched through Crane 410 and Idlechik (Handbook of Hydraulic Resistance) and they don't cover what I'm after.

cheers

Kennez

 

[johnp]

For pressure loss calculations Tees are considered to be equivalent to, or a special case of, elbows. It is a pretty crude assumption, but it has been found good enough for most applications - particulary if there are only a few tees in the system.

Model the Tee as a Header with one inlet and two outlets. Give each a Coefficient of Enlargement, or Contraction.

You can calibrate your model against quoted head loss Coefficients for Tees, and adjust the Coefficients to values that make sense to you. That way you are going back to the basic Bernoulli equation, so the theory will be a lot stronger than blindly taking a value off a Crane Chart.

If you want anything more accurate than that you would need to set up a model test and measure the coefficients. Is the cost of the model testing justified for your application?