17 replies to this topic

[GANESHD]

Dear All,
Iam new to forum. I need some assistance on pump curves.

One of our plant pump runs on glycol solution and I need to check performance curve for a different work. I got the pump vendor performance curve (Head vs Q flow) graph which was made based on water as test fluid.
Can anyone guide me how should I convert the existing performance curve of water to glycol having density of 1040kg/m3 , viscosity 2cp.

I searched forum for similar discussion topic couldn't find one.

thank you

[fallah]

 

GANESHD,

 

Basically the "Head vs Q" curve of a pump doesn't change with a change in the fluid to be handled by the pump. The required power of the pump's driver will be affected by the fluid density change...

[GANESHD]

Thank you fallah for giving clarification.
In case for the for given same amount of power input will 'head' go down for glycol case as it more dense than water.

Also would like to know if it's really happen this way in plant. Correct me if Iam wrong anywhere , below is what I understand and take away points.

1) As fluid density increases power will go up and up until it trips on high current. The pump rpm will remain unchanged.
2) Head vs Q volume flow curve of glycol will be same as in water curve.

I have been out of Industry for some years so I have such doubts coming up.

[fallah]

 

GANESHD,

 

1) For the specified Q and H; yes

2) Yes

[Art Montemayor]

GANESHD:

 

Fallah's response is absolutely correct.  The attached document - which I highly recommend you read and study thoroughly - bears out what he states.

 

Contrary on what you are trying to do, the power required by a centrifugal pump is dependent on the amount of flow and its density - it is not the other way around, which you are referring to.  Simply put, work is a function of mass moved through a given distance.  If the mass increases for the same distance, the power requirement increases.

 

 Creating a Pumping System Head Capacity Curve.docx   640.27KB   193 downloads

[GANESHD]

Thank you very much Fallah & Art !

[breizh]

Hi ,

For you and others who are confronted with hydraulic calculations .

Enjoy the reading .

Breizh

Edited by breizh, 30 July 2017 - 02:27 AM.

[shvet1]

 
2) Head vs Q volume flow curve of glycol will be same as in water curve.

 

ISO/TC 115 disagrees with Fallah and Art Montemayor. Pump Q-H curve relies on viscosity.

See:

- ISO/TR 17766 Centrifugal pumps handling viscous liquids - Performance corrections

- ANSI/HI 9.6.7-2010 Effects of Liquid Viscocity on Pump Performance

 

In your case glycol has approximately the same viscosity as water has, so for glycol Q-H curve is the same as for water.

Edited by shvet1, 06 August 2017 - 03:07 AM.

[fallah]

 

 
2) Head vs Q volume flow curve of glycol will be same as in water curve.

 

ISO/TC 115 disagrees with Fallah and Art Montemayor. Pump Q-H curve relies on viscosity.

See:

- ISO/TR 17766 Centrifugal pumps handling viscous liquids - Performance corrections

- ANSI/HI 9.6.7-2010 Effects of Liquid Viscocity on Pump Performance

 

In your case glycol has approximately the same viscosity as water has, so for glycol Q-H curve is the same as for water.

 

 

shvet1,

 

I and Art have mentioned the above statement based on density change. It's obvious with considerable difference in viscosity the H vs Q curve should be modified based on relevant viscosity correction factor.
 

[manuelh]

It´s right 

Isn´t the same to pump honey that pump water or gasoline(not same viscosity) 

 

and if the pump has a frecuence variator( change the speed of propeller) change the curve

 

Manuel

[Takechi]

Dear all expert

 

I work in refinery and would like to consult all expert at the same topic.

 

As I read above, I understand that all the performance curve from vendor base on water, Am I understand correctly?

 

Salapao

[manuelh]

First you mut check what do you want to pump. 

Oli, honey, water,etc. 

 

Normaly centrifugal pumps  works with water. Gear pumps work with oil, bunker and the pump curve is based with mineral oil with a specific viscosity.

 

What pressure do you need ( meter of water colum, psi, bar,etc) 

How much flow?

 

First tell please that you want and then we can answer you more clear.

 

Manuel

[Takechi]

Manuel

 

I do not want to design the pump.  But I would like to know, when we see a pump performance curve, what fluid is the performance curve based on (based on water or based on the fluid identified in the process data sheet?).

 

Salapao

Edited by Art Montemayor, 30 September 2017 - 12:47 PM.
Spelling, grammar

[Art Montemayor]

Salapao:

 

All centrifugal Pump test curves are based on using water as the test fluid.  ----- at least, in the USA.

[breizh]

Salapao,

What is the issue ?  Hydraulic Power ?

Water is always used because cheap and available !

Good luck .

 

Breizh

[Takechi]

Dear Breizh

 

The issue are Head, power, efficiency

 

Salapao

[breizh]

Hi Salapao,

another resource to support your query.

many more using the search engine in this forum .

 

Breizh

[Takechi]

Thank you so much breizh

 

 

Salapao