Restriction orifice and fluid law of continuity
Restriction orifice and fluid law of continuity
(OP)
As far as I know a restriction orifice functions as 'choked flow' which limits the flow exiting the orifice.
In other words, the flow before and after the orifice would be different.
Wouldn't that violate the law of continuity?
In other words, the flow before and after the orifice would be different.
Wouldn't that violate the law of continuity?





RE: Restriction orifice and fluid law of continuity
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RE: Restriction orifice and fluid law of continuity
RE: Restriction orifice and fluid law of continuity
Law of continuity state that flowrate would remain at 100m3/hr after it passes the orifice - the velocity is higher than before, and pressure drops.
Where does the term 'choke' in a restriction orifice fits in?
RE: Restriction orifice and fluid law of continuity
I'm sure Wikipedia can help you a bit more...
Is this an idle query or do you have a practical issue to address?
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Restriction orifice and fluid law of continuity
There is a header pipe (DN 200) with four pipes (DN 100) attach to it. These four pipes are equally distributed among them.
Two out of the four pipes have orifice in them with 30mm hole.
The four pipes function are to inject sodium hypochlorite to our seawater intake to suspend bacterial growth.
I've been observing that the pipes that have orifices in them does not inject the sodium hypochlorite compared to the other two.
RE: Restriction orifice and fluid law of continuity
If this is a one way header and the first two have orifice plates, it sounds like an attempt to distribute flow more evenly across the four pipes that may not be working as intended. Are all the pressures downstream exactly the same?
how do you know nothing is getting through the orifice plates?
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Restriction orifice and fluid law of continuity
The whole system would balance out though depending on the resistances in the four lines.
If you are getting zero flow in the lines with orifices though, is it possible for the orifices to be blocked?
Cheers,
John
RE: Restriction orifice and fluid law of continuity
RE: Restriction orifice and fluid law of continuity
Has anything changed since the original design (less flow?) Orifice plates can work well to balance flows, but need fixed conditions. The fact they all work when only one valve is open suggests that either they are only designed to work with one valve open or the flow rate through the system has changed. I still think they are in the wrong pipes as you have tagged them.
That vertical drop to the channel looks quite interesting. Is there some sort of nozzle on the end restricting flow or is it open? The pressure in that header might be less than atmospheric unless your flow rate is very high or there is something providing a pressure drop at the end equal to the head of the pipe drop.
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Restriction orifice and fluid law of continuity
The vertical drop goes down 12m and ends with an end plate. There are holes 15mm in dia at few intervals along the pipe. No nozzles.
RE: Restriction orifice and fluid law of continuity
first off I would swap the pipes with and without orifice plates and see how that works.....
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way