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-   -   Radial velocity and tangential velocity on centrifugal fan, (https://www.cfd-online.com/Forums/fluent/118037-radial-velocity-tangential-velocity-centrifugal-fan.html)

 johnnyp May 20, 2013 03:36

Radial velocity and tangential velocity on centrifugal fan,

Good morning,

How I can calculate axial velocity, radial velocity and tangential velocity for an centrifugal fan ?

Only what I know is outlet mass flow (Q [m^3/s], speed of motor [rpm], pressure at outlet from fan.

The axial velocity I can found it from relation Va=Qout/S (considering that Qout=Qin). For tangential and radial velocity, which is perpendicular to axial velocity, I found some formulas which take into account speed of motor, but the results are different (I'm sure that I do an mistake somewhere, but I don't know where).

So, I will appreciate your support if somebody can help me to resolve my problem with the correct relation.

The model of fan used is produced by euroventilatori and have code: EU 312.

The only what I need is some relation of calculus in which based on producer description of fan, I can determinate radial velocity and tangential velocity. This relation serve as input to Fluent.

Thanks in advance to all community for support.

Any advice, suggestion or support is appreciate

Best regards.

 oldisbest May 20, 2013 04:11

Quote:
 Originally Posted by johnnyp (Post 428638) Good morning, How I can calculate axial velocity, radial velocity and tangential velocity for an centrifugal fan ? Only what I know is outlet mass flow (Q [m^3/s], speed of motor [rpm], pressure at outlet from fan. The axial velocity I can found it from relation Va=Qout/S (considering that Qout=Qin). For tangential and radial velocity, which is perpendicular to axial velocity, I found some formulas which take into account speed of motor, but the results are different (I'm sure that I do an mistake somewhere, but I don't know where). So, I will appreciate your support if somebody can help me to resolve my problem with the correct relation. The model of fan used is produced by euroventilatori and have code: EU 312. The only what I need is some relation of calculus in which based on producer description of fan, I can determinate radial velocity and tangential velocity. This relation serve as input to Fluent. Thanks in advance to all community for support. Any advice, suggestion or support is appreciate Best regards.
What did U mean?
Axial, tangential, and radial velocity can be output in Fluent. For a centrifugal fan, if you know the mass flow and fan rotating speed, I think you can model this problem with whole configuration (fan, fan shroud) with MRF (Multi-Reference Frame).

Otherwise, if you want to know detailed flow characteristics between blades more accurately, you can also model with only one blade with periodic flow and sliding mesh, however, you need to know the radial velocity as input (for centrifugal fan, axial v at inlet can be neglected? radial v can be calculated from mass flow).

 johnnyp May 24, 2013 07:10

Good afternoon,

Thank you for indication. My problem is the formulas with which I can determinate axial velocity, radial velocity and tangential velocity.

I am not sure about the formulas with which can be determinate the velocities.

I want to use for volume of air which compose the fan, replace their domain as fan (with tangential velocity and radial velocity).

I waiting yours suggestion, indications or other idea.

Thank you for support.

Best regards.

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