## Pipeline Flow - FDTF

## Pipeline Flow - FDTF

(OP)

Good Evening,

I am currently creating a new calculation spreadsheet, part of this is a back pressure calculator which shows the type of flow using the churchill friction factor, this is shown graphically on a moody diagram as per the below image. However, I have multiple pipeline sections with multiple fluids available, so am trying to get excel to output the type of flow (eg. laminar, transitional, turbulent and FDTF). I cannot however figure out how to get excel to automatically determine this, without needing dozens of moody diagrams and the engineer to visually check these each time. Even if I can get the FDTF line to plot and then get excel to determine if the result is above this line. However, thus far I have had no luck.

Any assistance appreciated.

## RE: Pipeline Flow - FDTF

This might give you some more ideas to move forward. I'll probably go back to my own sheets and see if I can use these formulas as well.

## RE: Pipeline Flow - FDTF

Do you know if there is a formula for the curve representing the FDTF boundary?

Another way I have tried is by using various friction factor equations which claim to only work for one flow regime, then comparing the churchill value to these values, however I have not been able to get it to give the correct flow type with any reasonable repeatability.

## RE: Pipeline Flow - FDTF

EDIT:

Rounding to 3 decimal places, with double Re, seems to work well apart from at the boundary region, where it isn't overly accurate, better than any results i've achieved to date however.

## RE: Pipeline Flow - FDTF

Have now got it to determine if FDTF or Laminar. Couldn't get transitional so am counting transitional as everything not Laminar or FDTF. For anyone interested, code below:

Re = cell C34

2Re = cell C53

f - original - cell C57

f - 2Re = cell C56

Churchill A =POWER(-2.457*LN((POWER((7/C53),0.9)+(0.27*(B20)))),16)

Churchill B =(37530/C53)^16

f - 2Re =8*((8/C53)^12+(C54+C55)^(-1.5))^(1/12)

FDTF True/False =IF(ROUNDUP(C56,3)=ROUNDUP(C57,3),TRUE,FALSE)

f - laminar = =64/C34

Laminar True/False =IF(ROUNDUP(C60,3)=ROUNDUP(C57,3),TRUE,FALSE)

## RE: Pipeline Flow - FDTF

One way of identifying whether you are in the FDTF zone would be to calculate the friction factor using the Churchill equation and also with the von Karman equation i.e. f = 1/(2 x log

_{10}(3.7/(e/d)))^{2}If the Churchill and von Karman values are "sufficiently close" then you are in the FDTF zone.

Katmar Software - AioFlo Pipe Hydraulics

http://katmarsoftware.com

"An undefined problem has an infinite number of solutions"

## RE: Pipeline Flow - FDTF