4 replies to this topic

[raju.kct]

Hello Sir,

 

I am trying to estimate the time required to empty a tank which has initial liquid level of H and an Orifice diameter of D but additionally a Flat plate kept at a distance d from orifice opening. Similar to an arrangement is shown in Figure.

 

I could not get clue on calculating the discharge coefficient for this restricted orifice due to the flat plate.

 

The flat plate is attached to a valve which is used for draining tank. This arrangement make the flow though, a kind of vertical ring section. Can I use the developed rectangular area as flow area for finding discharge?

 

Please give some reference on similar situation.

 

Thank you

 

Attached Files

•  Orifice.jpg   14.31KB   1 downloads

[Pilesar]

I would determine the cross-sectional area of the flow restriction and then calculate an estimated flow as if there were only a single orifice of equivalent area.

[breizh]

Hi,

I will follow Pilesar's suggestion .

[latexman]

A picture of the real thing would be interesting.  The drawing implies D ~ 2d.  That would make the "window" d x 6.3d.  Is there any ability to raise the obstruction to control the flow, or is it fixed?  I suspect it's fixed and once the fluid comes through the D orifice and valve it can be considered open air, gravity flow.  If so, I would ignore it in the calculation.  Don't ignore the outlet D (K = 1) and the valve (K = ?).

 

Btw, what is the fluid?  Newtonian or non-Newtonian?  Viscosity?  That may make one reconsider.

[raju.kct]

Thank you everyone for your kind suggestions.

The area pi()*D*d could be used as an equivalent orifice area since flow happens through the periphery?

The medium is liquid fuel which is a Newtonian fluid.

On the position of Flat plate, the objective is to arrive at an optimum (and fixed value of) 'D' and 'd' which meets the time required to empty the tank (to achieve required average drain rate).

Please suggest some estimation methodology.

 

Thank you