Pumps and Pump System Calculations: Units

[Ben_Hagler]

Requesting Tips, Tricks and Advice

User Level:  Novice ... But have several 

Subject: Pumps and Pump System Calculations

I am working on some calculations templates for my daily work related to centrifugal pumps and pumping systems. I am having difficulty in developing a template that can display units in imperical and or metric units using normal industry standard formulas. I can fake it with MathCad but it does not look professional. Can someone provide me tips on the best way.

Example Equations:
1) Pump Brake Power (bop) = (Head [feet] * Flow [gpm] * SG) / (3960 * Pump Eff [%])
2) Pump Pressure from Total Dynamic Head and SG [Specific Gravity]: Pressure [psi] = (TDH [ft]* SG)/2.31
3) Specific Gravity [SG, SSG, %CV or %CW]. Calculation liquid SG using any combination of Solids SG, Slurry SG, % concentration by volume and % concentration by weight.
4) HazenWilliams methods with C value
5) I have several very special proprietary (secret) imperical formulas that have been developed through testing and their units cannot be rationalized. I would like to develop a method for using this equation.

[ValeryOchkov]

1)

[Ben_Hagler]

Well... that is awesome... got it.  Just need to think different.  Thanks.

[terryhendicott]

Hi,

5) I have several very special proprietary (secret) imperical formulas that have been developed through testing and their units cannot be rationalized. I would like to develop a method for using this equation.

Easy say your imperical formula was for speed of a log in a river based in diameter in cm and length in feet then

gave the answer in knots.   Once the definition is made you can enter D in imperial or metric and it is converted to cm internally to suit the units of the empirical equation.

[FredLusk]

For Hazen-Williams C, the procedure is to solve the equation for C, then reduce the units on the other side of the equation to see what units you need to attach to C to make the equation work.  A similar procedure works for all empirical equations.  For C, the attached units should be in the form of (L^0.37)*(T^-1).  Alternatively, you can attach these units to some other part of the equation.  Just make sure the units on each side of the equation are the same.