|
[Sponsors] |
![]() |
![]() |
#1 |
New Member
prashanth
Join Date: Mar 2017
Posts: 2
Rep Power: 0 ![]() |
I am new to CFX.
I am working on centrifugal compressor for small turbojet engines. I created the geometry using bladegen, meshed it in turbogrid(only one blade with periodic boundary). 1.5 million cells. geometry has three domains: 1.Inlet 2. Impeller 3. outlet inlet and outlet are stationary and impeller is rotating at 43250 RPM. interfaces are connected using frozen rotor. It is a steady state problem. Total energy including viscous dissipation is used. ideal gas. Inlet boundary conditions are Stagnation pressure and Stagnation temperature. Outlet - mass flow or static pressure. I need to plot performance of compressor for different mass flow rates. From basic calculations the design exit pressure is 400 kpa. so, I varied exit pressure from (200 kpa-380 kpa) from results it is observed that mass flow is almost constant around(5.2 kg/sec) . After 380 kpa solution is not converging below 10^-3 and mass flow is observed to be very low(0.75 kg/sec). I tried with mass outlet boundary condition(4.2-5 kg/sec) - but this is having converging issues. I cannot find what is problem with mass flow boundary condition at exit. In Solver control advanced options,compressible control and High speed numerics is switched on. please help me with this problem i am working on this for past 1 month. thanks in advance |
|
![]() |
![]() |
![]() |
![]() |
#2 |
Senior Member
Join Date: Jun 2009
Posts: 174
Rep Power: 17 ![]() |
Beyond 380kPa, your compressor approaches stall.
|
|
![]() |
![]() |
![]() |
Tags |
centrifugal compressor, centrifugal impeller, surge in compressor, transonic compressor |
|
|
![]() |
||||
Thread | Thread Starter | Forum | Replies | Last Post |
Out File does not show Imbalance in % | Mmaragann | CFX | 5 | January 20, 2017 10:20 |
Want Impeller Driven Fluid Flow: What Inlet and Outlet BC to use for Centrifugal Pump | Zev Xavier | FLUENT | 3 | May 9, 2016 06:42 |
Problem rose from centrifugal impeller | tim_shute | FloEFD, FloWorks & FloTHERM | 6 | January 31, 2012 20:06 |
[ICEM] Meshing a centrifugal compressor impeller | Mitpostdoc | ANSYS Meshing & Geometry | 8 | February 25, 2011 10:51 |
[GAMBIT] influence between angle in impeller blade and centrifugal pump performance | barak182 | ANSYS Meshing & Geometry | 2 | August 18, 2010 03:07 |