I have to analyze an existing ammonia line to estimate the pressure drop in it.
The line is designed to transport liquid ammonia. I can compute the pressure drop with standard friction factor approach. If I reach a point were the pressure is small that the corresponding vapor pressure, partial vaporization is to be expected.
What method is recommended to compute the pressure drop from that point onwards??
I have a two phase flow textbook, but guidance would be helpful as to what is the recommended procedure.
Best regards.
Look for it in Google. t he ammonia is a refrigerant and Emerson Vilter has a manual that may help you.
Also, look for the DX AMMONIA PIPING HANDBOOK of B. I. Nelson that you can download from Google.
Flow in a two phase state is quite complex. Basically, depending on the vapor fraction different correlation should be used . However, some correlation are more general and can be used in the whole two phase domain. These correlations are discussed in this article :
Ould Didi, M. B., Kattan, N. & Thome, J. R. Prediction of two-phase pressure gradients of refrigerants in horizontal tubes. Int. J. Refrig. 25, 935–947 (2002).
With this method you keep the traditional linear pressure drop formula, but you have a specific pressure loss coefficient.
- Badges
- Science topic
- Similar topics
- Thermodynamics
- Pressure