Blade design for a cyclonic separator (swirl vanes)

[q8rix]

Hello
I have been doing alot of research trying to find an answer but still i couldnt :S so i will show you the details and then will ask the question
here you go

https://dl.dropbox.com/u/86410588/fan1.zip

so if you look at the fan and cyclone (which where the fan is going to be installed) i know there are some problem to fix and some of the problem i cant find an answer for it here are the problem
1- how can i decide the blade curve radius ?
2- the top cone on what basis should i design it ?
3- the bottom cone i know it should be 0 radius at the tip
4-the blade height on what basis should i design it as well
5- on what basis i am going to shape the blade (Airfoil)
and yes i am using solidworks 2012

 

[MikeHalloran]

You do realize that a cyclonic separator normally does not include a fan, right?



Mike Halloran
Pembroke Pines, FL, USA

 

[q8rix]

i know thats the problem i cant find alot of details on this many of cyclonic separator available are using the tangential inlet while this separator is using the fan (swirl generator) and the flow exit from the bottom of the cyclone where i will add a hole for the water outlet

 

[1gibson]

The "fan" will erode away if there are solids in the fluid, which is the purpose of most cyclone separators.

If this is an oil/water separator and there are no solids then it may work, but you are turning a passive component into an active one. Are the production, and then utility costs, justifiable? Even if they are, you still might be better off having a separate pump pushing fluid into a traditional, passive cyclone separator.

If this is an air/water separator, same story I think, separate fan. Unless you have packaging limitations, in which case you are really in a tight spot.

 

[q8rix]

well the problem is i cant design something else this is my Final year project .
so far 5 is in progress it seems the airfoil is used to reduce the pressure drop (drag force) also 1 is linked to 5
oh i just notice something , it seems you are not allowed to answer students :S

 

[MikeHalloran]

If the problem is interesting, nobody cares if you are a student.

Let's review.
A classical cyclone separator comprises a cylindrical chamber with a tangential inlet for dirty fluid,
below which is a cone with a small aperture at its apex for metered discharge of the 'dirt' or water.
Dirty gas flows helically down the cone, slinging the dirt to the cone's surface, where the dirt flows down.
When the dirt-reduced gas reaches the bottom of the cone, it flows helically upward within the cone of downflowing dirty gas, where it recovers some of the kinetic energy it gave up by shear against the upflow on the way down, and exits axially upward, with considerable swirl, through a nipple extending downward from the roof of the cylindrical inlet chamber.

You've got a usable cone. The rest of your stuff doesn't map very well to the job. If you are starting with an axial flow down, and inducing rotary motion by means of vanes, well, that might sort of work, but you still need a coaxial gas effluent pipe in the center of the inlet. You can't get the gas to go out of the bottom.

Frankly it appears that you started 'designing' components before figuring out how they have to interact in order to work. It's an easy trap to fall into with CAD tools. Try not to do it when someone is paying you for the results.



Mike Halloran
Pembroke Pines, FL, USA

 

[1gibson]

If someone asked you to design a wheel from scratch, you would still start with it being round. Depends on your working fluid (abrasive content), but relying on vanes of any sort is either a bad, or a really bad idea. They will not last.

Design a cyclone separator with renewable wear surfaces
Design a cyclone separator with a standard housing, and replaceable "guts" for different flowrates / different fluids