Pressure drop

[POPPASMURFF1942]

I have a 2"line with 10,000# of steam a 60 psig entering a 8" line that has 8,000# of 3 psi steam flowing in it in it. What pressure can I expect to see in the 8" line. A little above my head.

 

[racookpe1978]

What method have you used to calculate the new net flow in the 8 inch line so far?

If the 8 inch line were ever blocked, it WILL see a pressure surge, then at least a static pressure of 60 psig after the steam hammer stops. What is the pressure and temperature limits of the current 8 inch line?

 

[POPPASMURFF1942]

Line is open ended to a KO pot. Calculation of new net flow 10k plus 8 k is all I know

 

[LittleInch]

That is not a solvable problem as presented. At the point where the two systems meet the pressure will be the same or you need to throttle your 2" line down to meet the 3 psig limit or to limit flow to 10,000 lbs/hr.

If you're looking at a current 8000 lbs per hour? at 3 psi and you're going to add a further 10,000 lbs/hr, your total flow rate more than doubles, so your pressure drop will go up by a factor of about 4. however this then reduces the actual velocity of the steam and so you're probably looking at about double the current pressure drop, but simple to do a calculation using some proper steam software pressure drop calcs. Now it then depends if your supply of steam in the 8" line can cope with the increased back pressure or not. However your 2" line must somehow be controlled to 8000 lbs otherwise it will become open ended and reach near sonic velocity and lot more than 10,000 lbs/hr.

Try sketching this out so we can see what you mean then revert.

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[racookpe1978]

If the two pipes intersect with the HP 2 inch aimed "upstream, the steam will exit, expand slightly and stagnate, and block flow of the LP steam in the larger pipe.

If "aimed" downstream like a venturi, the 2 inch flow will accelerate the LP steam slightly - IF it's going into a very large receiver.

But it smells like a homework problem..

 

[LittleInch]

True, I was just thinking about a tee type connection so essentially neutral.

don't think it's homework - poppa has been registered since 2006...

The two systems as written are simply not compatible so needs a bit more info...

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