Pump energy at different fluid temperatures

[Mrrobottoe]

Hello,

I am trying to figure out the relationship between temperature of the pumped fluid and the amount of power the pump uses. I know that when the temperature is lower the kin vicosity will be higher which will make pumping harder, but is there any sort of table that shows this or formula i can use to figure something out? even a ballpark figure would be fine.

thanks.

 

[BigInch]

If your viscosity is less than 500 cP, there is basically no change.

If you're near or over that, see

http://www.mcnallyinstitute.com/14-html/14-04.htm

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"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[Artisi]

Temperature can have an effect on SG which will influence power, again unless you are splitting hairs it's probably not worth considering.

 

[Mrrobottoe]

when pumping things such as fuel oils it is worth considering. Number 4 oil could require about 60% less hp to be pumped at 150 deg f as opposed to 50 deg f. Just wondering if anyone had any othe input on this.

 

[BigInch]

The way you phrased the original question, I thought you were referring only to the effect on the pump. Of course the effect in the pipeline can be much more significant, especially if the pipeline is long, transit time is high and the oil cools back to near ambient temperatures. If that is the case, high inlet pressures are usually needed (especially during start-up) because the temperature is a log function of length and cooling is relatively fast. That can be a big problem when flowrates are towards the low side. Here's a chart that shows the viscosity change with temperature. See attachment.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/

 

[Artisi]

Ditto to BigInch's comment re effect on a pump - temp change on a "system" is another story.

 

[Mrrobottoe]

the original questions asks about pump energy at different fluid temperatures. Meaning how much energy the pump has to exert when the fluid is at different temperatures. Regardless of piping, when pumping a viscous fluid at room temp as opposed to boiling, the fluid will thin and become easier to pump. I was jsut looking for a way to comfirm that and back it up with numbers. Biginch's first post was very helpful, thank you. If anyone else has input then thank you as well.

 

[BigInch]

Cool.

**********************
"Pumping accounts for 20% of the world’s energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies)

http://virtualpipeline.spaces.live.com/