1 reply to this topic

[stu]

Dear All,
For sizing two phase line what will be recommended velocity. Whether we consider Gas flow & liquid flow separately?Please explain how to calculate the velocity.
Regards,
Stu.

[JoeWong]

stu,

This subject can be very completed by considering phase separation, gas and liquid flowing in different velocity, entrainment liquid into gas, liquid droplet in vapor coalescing and deposit on liquid in the pipe run, disturbance wave spreading, Secondary flow, flow pattern, etc...Just too complicated and too wide to discuss...

but you may analyze it in a simple way by considering they are homogeneous.

The properties e.g. density, viscosity, etc can be analogue homogeneous properties but this will increase the error and accuracy between calculated value and real value.

you may also consider to use empirical equation. Read more in GPSI Fluid flow chapter.

For criteria, each company may have their own criteria. Again, these criteria is subject to balance between material cost and energy cost, design life, vibration level, noise level, etc. For offshore application, one of the common published reference is API 14E using C-factor method.