inverted siphon 4

[engrsalah]

i have to design an inverted siphon. but situation is
a conduit is taken out from dam. water is to be delivers to inverted siphon immediately after impact wall. but the level of invert of siphon is higher than the conduit outlet level. now my question is whether siphon will pass water with out any disturbance or to lower the invert level of siphon and create a head on it. so that it could pass it to outward.or any other suggestion. here is the detail sketch and design calculations

 

[LittleInch]

Please sketch this out with heights, water levels etc and dimensions so we can understand it.

What's an impact wall?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[cvg]

as long as the upstream water surface elevation (lake level) is higher than the tailwater pond level at your energy dissipater, than you can theoretically siphon water. You will need enough head to overcome friction losses. And you cant go too high over the dam or your pressure (at the top) will be less than atmospheric and you will break the siphon.

this has been discussed before, see search of this website:

http://www.eng-tips.com/search.cfm?...iphon&t=&h=&searchSite=1&searchArea=1&d=1&s=1

 

[pennpiper]

I know a "siphon" is an inverted "U" with the intake leg shorter than the outlet leg.
What is an "inverted" siphon?


Sometimes its possible to do all the right things and still get bad results

 

[cvg]

here is an interesting version of an inverted siphon. I believe the OP is looking at a non-inverted one, if not then he will need to post a sketch in order to clarify what he is doing.

http://aggie-horticulture.tamu.edu/archives/parsons/riverwalk/Images/slide79.jpg

 

[engrsalah]

here is detail of sketch and calculation of inverted siphon please see and then recommend.

 

[bimr]

You have to lower the invert level of siphon and create a head on it. See the image of an inverted siphon.

 

[engrsalah]

bimar can you write reference of this image please

 

[LittleInch]

I really don't fully understand your drawing.

Section AA - where EXACTLY is the water level of the dam.

The bottom of the pipe is 466.92m, which equates to your start point on the profile.

I didn't follow the entire calculation, but it's clear you have very small margins here.

clearly, the lower your inlet invert level the better to reduce inlet losses, but the key item driving everything is the differential head between the dam water level and the outlet invert level.

That's what I don't clearly get from your drawing.

Most people would just call this a pipeline, not an "inverted syphon". The fact it has such a dip is not of any real importance, it's the fact that the pipe does not go above the inlet level and the end point is below the inlet level. Therefore there will be some flow, but how much is not clear.

The only issue becomes whether there is sufficient velocity to make sure you don't start to gather debris / solids at the base of the dip. 4.3 ft/sec should be enough to keep it all in suspension

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[bimr]

bimar can you write reference of this image please

Wastewater Collection by Metcalf & Eddy has a design procedure for an inverted siphon (depressed sewer).

 

[cvg]

its really not that difficult. you will need sufficient head to overcome inlet, outlet and bend losses as well as friction losses. you will need to avoid sediment deposition in the low spots. you will need to make sure there are no places for air to accumulate. the metcalf and eddy reference will suggest that more than one pipe is better so that you can maintain full flow in the pipes at different flow rates. that is the reason for the inlet and outlet structure splitting into three different sized pipes as shown in the detail.

 

[engrsalah]

THANKS I FOUND THAT YOUR REPLY WERE VERY HELPFUL ESPECIALLY OF bimr. thanks once again