hi

I calculate two stage of steam turbine (high pressure stage), i have problem with mass flow - it is much lower than for 0D calculations (20%). I used both coupled and segregate solver. can you help me?

did u make grid indpendence study?

yes I made, and for all cases mass flow is similar I also checked different turbulence models and the problem still exist for different cases

can u send ur goemtry and boundary conditions file

no i cannot

Does your 0-dimensional model take into account effects like area shrinkage due to boundary layers, pressure losses at tip gaps, boundary layer separation, radial flow, etc.? 20% is not that much to me!

Razvan

this 0-dimensional model seems to be ok, it takes into account all the mentioned efects, maybe the problem are the magnitude of pressure losses (for 0-D model). the factor for calculation of them is not proper. i calculate partial admission stage (i have four valves) with the second stage. maybe the problem is with the area between these two stages (it is quite big) i am not sure. if i calculate the case where 2 valves are opened the mass flow is ok, for case with 4 opened valves the mass flow differences are big. when i calculate only admission stage the mass flow rate from my calculation is equal to the one from 0-D. so i am not sure what to do yet.