|
[Sponsors] |
Simple setup with mass inlet en pressure outlet but no convergence |
|
LinkBack | Thread Tools | Search this Thread | Display Modes |
October 24, 2019, 02:57 |
Simple setup with mass inlet en pressure outlet but no convergence
|
#1 |
New Member
Benoit
Join Date: Oct 2019
Posts: 3
Rep Power: 6 |
Hello everybody. I'm new to CFD. Please find screenshots in attachment to clarify my case.
I'm trying to run a simple axisymmetric flow case: 2 mass flow inlets (air), 1 pressure outlet, 1 axis, and some walls. Fluid: all air. Flow: inviscid. Solver: density based. In the future, I want to add and change some elements of the case, but for now I wanted to start simple. Apparrently I'm already doing something wrong. The problem: at first, the solution seems to converge, but it happens very slowly (the total mass outflow approaches the sum of both mass inflows), but in the end it diverges. When I choose pressure inlets instead of the mass flow inlets, the solution converges very quickly without any problem. Why is it so different with mass flow inlets? I need mass flow inlet BC because of the nature of the problem I want to simulate later on. What am I doing wrong? Thanks! |
|
October 24, 2019, 03:55 |
|
#2 |
New Member
Arnie
Join Date: Mar 2017
Posts: 27
Rep Power: 9 |
Hi Benoit85,
Are you sure that the inlet BCs you have modeled are realistic/representative of actual equipment/system ? It looks to me like you will get significant reverse flow at the inlets and a very unstable system/analysis. |
|
October 24, 2019, 04:15 |
|
#3 | |
New Member
Benoit
Join Date: Oct 2019
Posts: 3
Rep Power: 6 |
Quote:
I just ran another simulation with Standard k-eps turbulence model and you can see the results in attachment. It converges way too slow, and actually, it still isn't really converged (see corner at outlet). |
||
Tags |
air flow inviscid flow, convergence failure, mass flow inlet, nozzle, pressure outlet |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Match Pressure Inlet/Outlet Boundary Condition Mass Flow Rate | MSchneid | Fluent UDF and Scheme Programming | 3 | February 23, 2019 06:00 |
Adjuting oulet pressure till inlet pressure reaches a certain value in timestep | pvpnrao | OpenFOAM Running, Solving & CFD | 2 | September 11, 2018 10:14 |
Pressure Boundary Inlet and Outlet | AS_Aero | CFX | 5 | March 28, 2018 10:46 |
Setting both inlet and outlet with pressure boundary conditions | ahmadbakri | CFX | 0 | July 1, 2015 04:06 |
what the result is negatif pressure at inlet | chong chee nan | FLUENT | 0 | December 29, 2001 05:13 |