|
[Sponsors] |
March 12, 2007, 14:12 |
re: Massflow reset in CFX 10
|
#1 |
Guest
Posts: n/a
|
Hi,
I'm inducing flow in a model via the massflow option. The massflow is 0.18 lbm/sec. This is inputted into the inlet and outlet (mass conservation). When the model is ready, it shows a proper distribution of massflow (equal throughout) but the inlet and outlet values are between 1E-4 and 3E-3 lbm/sec. I'm stuck trying to figure out how on earth 0.18 went to 0.001. Any suggestions? I feel as though there is some check box lurking in the background I should've checked. For troubleshooting, the inlet was setup with the massflow, the outlet condition was setup with a massflow and the "Scale Mass Flows". Thanks! M |
|
March 12, 2007, 15:14 |
Re: re: Massflow reset in CFX 10
|
#2 |
Guest
Posts: n/a
|
Setting mass flow on both the inlet and outlet BCs is going to lead to issues.
Set a mass flow at the inlet and let the outlet calculate itself with an outlet-type BC. |
|
March 12, 2007, 18:06 |
Re: re: Massflow reset in CFX 10
|
#3 |
Guest
Posts: n/a
|
What would you suggest the outlet condition to be? I would know most if not all the inlet conditions, but the outlet is an unknown. By forcing the massflow at the outlet I was thinking I'd have something to plug in. While its not a big thing with most of my models, there are a few where I need to setup a design and examine the differential pressure CFX calculates (outlet pressure/flow unknown).
|
|
March 12, 2007, 21:12 |
Re: re: Massflow reset in CFX 10
|
#4 |
Guest
Posts: n/a
|
your question is not closed at all for such boundary conditon.(U,v,w,P),where is the p reference?
|
|
March 14, 2007, 22:51 |
Re: re: Massflow reset in CFX 10
|
#5 |
Guest
Posts: n/a
|
ok, masflow outlet and total pressure inlet?? works fine if the flow is not choked.
|
|
March 16, 2007, 21:08 |
Re: re: Massflow reset in CFX 10
|
#6 |
Guest
Posts: n/a
|
Ok, I'm using for a particular model the inlet massflow (which is now working) and an outlet pressure condition of zero psi (good call Joe). This will work for this model. If there is a reference pressure (say 300 psi) how will the zero pressure outlet effect it? I have a model where I know some basic flow into the part, the reference pressure, but I know nothing of the outlet. In fact that is what I'm trying to figure out is whether the set of designs will improve dp and cooling of the device. Klarke, I don't know quite what you are asking. Now the model I'm working on has empirical data and so I'm busy benchmarking CFX against it. As for geometry, its a simple water jet blasting a hot plate. I have some volumetric heating questions but I'll save 'em for another thread. Thanks!
|
|
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Pros and Cons for CFX, CFdesign, COMSOL | Val | Main CFD Forum | 3 | June 10, 2011 03:20 |
MassFlow Function? Absolute MassFlow? Failure in Caclulation | eRzBeNgEl | CFX | 0 | May 5, 2011 10:46 |
CFX overpredicting turbine massflow | sherifkadry | CFX | 3 | February 1, 2010 04:15 |
PhD using CFX | Rui | CFX | 9 | May 28, 2007 06:59 |
CFX 4.4 installation problem | Pandu Sattvika | CFX | 1 | December 1, 2001 05:07 |