CFD Online Logo CFD Online URL
Home > Forums > FloEFD, FloWorks & FloTHERM

Bellmouth Modelling

Register Blogs Members List Search Today's Posts Mark Forums Read

LinkBack Thread Tools Display Modes
Old   November 10, 2008, 15:02
Default Bellmouth Modelling
Mike Brown
Posts: n/a
Hopefully someone here finds this very easy and can offer tips. I'm trying to model the flow of water being sucked into a pipe bellmouth from infinate water supply like a lake. So far i've set up a thin feature 2m x 2m x 2m (30mm Thick) box around the bellmouth where the water is. I've capped the end of the tube to which the bellmouth is attached and applied a sucking flow on the inside surface of this. My main problem is defining the water. The box would need to simulate the lake, therefore the top is at atmospheric pressure. The sides would be under hydrostatic pressure and the base the pressure 2m below the surface. This doesn't work however. Any tips would be largely appreciated. cheers mike
  Reply With Quote

Old   November 11, 2008, 04:00
Default Re: Bellmouth Modelling
Matic Grom
Posts: n/a

As i understand you, you are trying to specify two boundary conditions as pressure openings? A also tried this sort of simulations in FloWorks, for example flow through piping systmes and it does not work. As much as I found out, you have to specify pressure opening and flow opening (outflow, inflow or velocity).

So my suggestion is, that you assume some outflow and run simulation. Then you check pressure on outflow opening. If it has value you would specify simulation is completed. If not, specify new outflow condition. You do that until pressure on outflow opening is equal (in reasonable tolerance) to pressure, you want to specify as outlet pressure.

I hope I helped.



  Reply With Quote

Old   November 11, 2008, 11:39
Default Re: Bellmouth Modelling
Mike Brown
Posts: n/a
Sorry Matic, I'm not trying to specify two boundary conditions as pressure openings, i was just explaining what i've done so far which is wrong. I'm trying to model the water flow around a bellmouth intake to a pump. Looking at how adjusting the shape of the bellmouth effects the fluid flow into it. Unfortunately Flowworks only allows internal flows such as pipe systems. To find a way around this i tried creating an infinate space around the bellmouth to simulate the water source. However, this is a lot harder than i thought.
  Reply With Quote

Old   November 14, 2008, 05:24
Default Re: Bellmouth Modelling
Posts: n/a
FloWorks is capable of simulating external flows as long as they do not involve free surfaces. You can solve your problem either as external or internal. For external problem, create your pipe as a channel in a massive of solid (i.e. as a cylindrical cut in a solid cube ). For example, if you want to calculate the flow in a 2x2x2 m cube near the bellmouth, your solid should have the section of 2x2 m and the pipe's length in the third dimension. Then specify the project in Wizard as external, don't forget to enable the Gravity physical feature in the direction of the coordinate axis defining the depth of the lake. On the Initial conditions step of the Wizard specify the pressure of 1 atm if the origin of your coordinate system is located at the top surface of volume or the pressure at the depth of 2 m if the origin is located at the depth level of 2m. Make sure that the Pressure potential check box is selected. Together with Gravity enabled this will provide the pressure gradient due to the weight of water. After Wizard adjust the computational domain size to include only the solid with channel and some fluid volume adjacent to the bellmouth (not protruding outside the section of solid normal to the bellmouth's axis!). Then cap the pipe's side where the pump is installed with the lid and specify mass or volume outlet flow rate. Now you can solve your project. For internal simulation, you have already done some part of the job by creating the box. You need only to enable Gravity in General Settings in the direction of depth axis, specify the pressure according to the location of origin, as I described above, enable Pressure potential, specify Environment pressure on the inside walls of the box (with the Pressure potential check box selected) and the pump outlet volume or mass flow rate at at the lid.
  Reply With Quote


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Modelling unsteady 2D aerofoil drag xlxc34 Main CFD Forum 0 June 24, 2011 04:42
bellmouth flow analysis munna1981 Main CFD Forum 3 February 14, 2011 13:04
Advice on multi-phase flow modelling Martin Main CFD Forum 3 October 14, 2008 05:16
how to ensure that your modelling is correct rvndr Main CFD Forum 7 March 1, 2004 13:21
Computational Modelling of Vortex Separators May Lim Main CFD Forum 6 November 13, 1998 13:36

All times are GMT -4. The time now is 21:16.