Piping Systems Fluid Flow

[SimonCurson]

Hello all,

Our company has just bought the simulation Piping Systems Fluid Flow and I am currently looking at the pressure drops for supply pipes. In an ammonia vapour line there is a Y-type strainer. The simulation can model a screen box (scaled/clean) by altering the Kf factor. By finding the correct Kf (or Kf calculated from Cv factor) for a y-type strainer, I would be able to model the strainer on the simulation. Does anyone know where I could obtain values of Kf for Y-type strainers? Flite Software who produced the simulation have suggested Handbook of Hydraulic Resistance 3rd Ed - IE Idelchik for previous queries, but I have not got access to this source. I have emailed several companies who manufacture Y-type strainers, but they do not have information on Cv or Kf values available.

Kind regards,

Simon Curson

 

[StoneCold]

Simon
Spirax Sarco has pressure drop tables and Kv values for Y strainers I am not sure if the Kv value is the same as the Kf value you are looking for but you can use the pressure drop tables to figure it out.
click on Product overview--Pipeline Ancillaries--Strainers and filters-- Download the Strainer Catalog. The info you want is towards the back.

Goodluck

StoneCold

 

[s0eebuch]

Try mueller also. Most sales reps are more than willing to help answer questions such as these, if they thing it will lead to a possible order!

 

[Montemayor]

Simon:

I have to ask a practical question. Why haven't you contacted the software company that wrote the algorithm you are trying to employ? It is obvious that they should have an answer for you in regards to how you employ their software. They must have had a reason for writing the algorithm without putting a K (resistance factor) for the conventional Y strainer. They either didn't care, didn't have the time, didn't want to do it, didn't want to spend the time/money to do it, etc., etc. But they must have had a reason. If your software is worth the price, they should back up the product with customer assistance and satisfaction - not just put you off with a reference. They should furnish the K value or the specific model value to substitute for it. That, to my mind, is the best and most direct method to employ in your case. I wish you luck in beating down their door for results.


Art Montemayor
Spring, TX

 

[Latexman]

Simon,

If memory serves me right, you will need to back calculate a K for each line size from the pressure drop (clean) versus flow rate graphs given by Mueller and Spirax Sarco. The pressure drop (dirty) will be determined by the pressure drop that is available at the minimum acceptable flow rate by the operating department.

Good luck,
Latexman

 

[SimonCurson]

I have contacted the software company about my problem but the have not got any K values for a y-type strainer. They only have an inline filter component, but i want to specifically model a Y-type strainer.

I can do this by altering the default Kf value(in the simulation) for the inline filter, to a Kf value for a Y-type strainer. The problem I am facing is that spirax sarco gives Kv values for the Y-type strainers, and not Kf values. They also give pressure drop/flow figures to determine the pressure drop for water. I assume i can determine the pressure drop from the flow rate ( of water) I am using, then back calculate a Kf factor using a the equation containing kf

Head Loss = fturb Kf V^2/2g.

Once i can calculate a Kf for water or steam, I then need to figure out a method of determining the same value for ammonia if any data is available,

Simon Curson

 

[katmar]

Simon,

You can use the numbers from the Spirax catalog with a little bit of manipulation.

The Kv numbers published in European publications are based on pressure drops in bar and flowrates in m3/h. You can convert these for use in the US system (USGPM and PSI) by noting
Cv = 1.156 x Kv.

The conversion from Cv to Kf is described in Crane manual 410 (Page 3-4, Equation 3-16, in my 1988 version). This gives
Kf = (29.9 x d^4) / Cv^2 where d is the pipe ID in inches.

Kf is independent of the fluid so you can use the values you derive this way for ammonia or water or steam. The only restriction is that you must be in the turbulent flow regime.

regards
Katmar