Anti vortex baffle in tank

[Shamoon85]

Hello,

I want to discuss some things about vortex breaker device installed at the fuel and oxidizer tank outlet. I have to do a study project in which I am supposed to add this device on outlet of a tank which is 200mm. I wanted to know that is there a thumb rule for device height; while device vanes are usually mentioned as 2/3 of the outlet diameter, how much should be the height of the vanes (or baffles)? The mass flow rate through this drain is 130 kg/s and the density is 780 kg/m3. Based on the formula (S = D +2.3 D Fr), this gives the submereged depth of 1.9 m. The tank height is 5 m. Isnt it too much height for a vortex device compared to tank height?

Please help

Regards,

SJ

 

[rb1957]

I don't know much of what you're talking about, but ...

I calc that the pressure head (pgh) is about 37500Pa (using h = 4.9m, to the CL of the outlet)
then the velocity of the outlet should be about 10 m/sec (sqrt 2gh)

but your velocity is about 1/2 this (5.3 m/s) = m_dot = density*volume_flow_rate, V_dot = Area*velocity ... velocity = m_dot/density/area

so I think your vortex breaker is meant to create a Cd of about 0.5.
I don't follow your calc for S ? Is Fr a (dimensionless) Froude number ?

another day in paradise, or is paradise one day closer ?

 

[Shamoon85]

yeah that is what i noticed too. The m_dot was provided to me. Fr is the dimensionless Froude number. S is the submerged depth and the formula of submerged depth was from a piping text book.