Pump efficiency calculated w/ temperature increase of liquid in pumps 1

[warneke]

I am looking for technical article in books or magazines giving details of meassuring and calculation of pumps efficiency by the temperature increase if liquids passing through pumps.
Can any body help me ?

Paul Warneke

 

[tstead]

Look in the Cameron Hydraulics Book. The equation for temperature rise in a pump assumes that the entire efficiency loss in the pump is turned into heat.

Temp Rise = H(1.0-E)/(778*EU)

Where H = Total head in feet
E = Efficiency of the pump
U = Specific heat of the pumped liquid in BTU/lb*Deg. F

All you do to get to this equation is take the power of a pump:
P (in hp) = TDH*GPM*S.G./(3960*Eff.)

That is how much power the pump needs to pump the fluid. Then assume an eff. of 1.0, this is the power need to pump the fluid if the pump were a perfect machine. The difference is the amount of power lost by other means (heating the fluid up and sound). If you assume the power required to make noise insignificant, then you can make the assumption that all of that lost power is transferred into heat.

Hope this helps.

 

Try a search for YATESMETER in the UK. Maurice Yates has written many articles on his device which has been widely used to find flow as well as efficiency of pumps via delta T.

 

[Beebe]

I have returned to my office at Monash University in Australia, and can now look up my notes.

At a pump conference in London, I found this empirical formular developed in the South African mining industry, and have changed it into SI units. It applies for water at up to 54 degC:

Efficiency = 100/ [1- (0.003(t -2) + 4160 (TR/TH)] where t is the inlet water temperature, degC, and TR is temperature rise. C deg, and TH is total Head, kPa

I have tried this on high pressure pumps and high water temperatures, and when steam tables are used the results are close.

Mechanical losses are not included, but these are insignifcant for any but very small pumps.

 

[jbuchyns]

ISO Standard #5198 makes reference to the thermodynamic method of Pump Efficiency measurement in its section 11. The methods are painstaking, but the science is clearly laid out. They refer to measurement or estimation of the "other" mechanical losses in the pump including heat dissipation through the pump casing, but these are considered to be too small to worry about.

Maurice Yates' articles are a very good resource as well.
We are using his rig, which is practical only above about 200 HP, for measuring our water system pump efficiencies, and would welcome any discussion on it's methods and uses.