Sonic velocity in Pipephase
Sonic velocity in Pipephase
(OP)
Hi, everybody!!!
I begin to work with the program Pipephase. And I have a some questions. What model in this program is used for calculation sonic velocity two phase flow? Why Pipephase calculated very high sonic velocity (250m/s)? On the Fortunati model the sonic velocity is lower (100m/s).
I begin to work with the program Pipephase. And I have a some questions. What model in this program is used for calculation sonic velocity two phase flow? Why Pipephase calculated very high sonic velocity (250m/s)? On the Fortunati model the sonic velocity is lower (100m/s).





RE: Sonic velocity in Pipephase
Comparing results (HEM vs. HNE) with Prode Properties I see that for low vapor fractions (say < 10%) predicted sonic velocities can vary substantially (say 10-50%) while agreement is good for other cases (considering a limited slip),
also, small differences in physical model (say fluid properties, phase equilibria as calculated with a multiparameter model, for example GERG 2008 or a EOS as Peng Robinson) can introduce large variations...
Similar comments for the model proposed by Fortunati which considers a polytropic expansion and physical properties are calculated at downstream conditions...
RE: Sonic velocity in Pipephase
The sonic velocity (or critical velocity) in two phases system is always lower than sonic velocity in a 100% vapor phase and 100% liquid phase. However in the Pipephase this rule isn't observed. The minimum of critical velocity in two phases system will be 0,5 at a liquid holdup. Calculation of sonic velocity in a 100% vapor phase is simple.
RE: Sonic velocity in Pipephase
HNE model gives different values within the two phase area but main differences are in the area 0.0 .. 0.1 liquid fractions where HNE do not predict those low values calculated by HEM.
Different methods (as, for example, the formula given in Two-Phase Flow through Wellhead Chokes) can return different values which are however suitable for specific applications..