9 replies to this topic

[raj shekhar]

Hi Cheresources team,

 

I hope you all the doing well.

 

I want to calculate the the temp. rise in centrifugal pump when the pump is dead headed. I got the formula from the below link -

 

https://powderproces...ature_Rise.html

 

I used the formula to calculate the temp. rise below is the calculations steps -

 

Shut off BHP    5 hp
Fluid handled by pump    Ethanol
Fluid density    49.25 lb/ft³
Fluid specific heat    0.6 Btu/lb.°F
Boiling point of liquid    172 °F
Pump casing volume    2.5 ft³
Weight of the fluid inside casing    123 lb
Temperature rise    2.9 °F/min

 

Temp. rise per min is around 3 deg F, it seems quite high. I need your views on this value. Am I missing something here.

Waiting for your valuable suggestions.

 

Thank you,

Raj Shekhar Ghosh

[latexman]

In my experience, that seems reasonable.

[Chemitofreak]

Hi,

 

Can we know the reason for calculating the temperature rise?

 

are you calculating the minimum re-circulation flow or something else? 

[fallah]

 

Temp. rise per min is around 3 deg F, it seems quite high. I need your views on this value. Am I missing something here.

Waiting for your valuable suggestions.

 

 

Hi Raj,

 

It's not so high and as latexman mentioned is reasonable...

[breizh]

Hi,

Consider the document attached to support your work.

Good luck

Breizh

Edited by breizh, 20 May 2020 - 02:49 AM.

[raj shekhar]

Hi,

 

Can we know the reason for calculating the temperature rise?

 

are you calculating the minimum re-circulation flow or something else? 

Hi,

 

The pump is used here for transferring Ethanol, as it's a flammable liquid I wanted to know what is the temp. rise if we dead head the pump for longer time. If the temp. rise is much higher I will go for a minimum re-circulation line.

 

Thank You,

Raj Shekhar Ghosh

[raj shekhar]

Thank you Latexman sir and Fallah sir for sharing your valuable experience with me. 

[raj shekhar]

Hi,

Consider the document attached to support your work.

Good luck

Breizh

Thank you Beizh sir for the document.

[Chemitofreak]

 

Hi,

 

Can we know the reason for calculating the temperature rise?

 

are you calculating the minimum re-circulation flow or something else? 

Hi,

 

The pump is used here for transferring Ethanol, as it's a flammable liquid I wanted to know what is the temp. rise if we dead head the pump for longer time. If the temp. rise is much higher I will go for a minimum re-circulation line.

 

Thank You,

Raj Shekhar Ghosh

 

 

Please note that minimum re-circulation is required for two reason

 

1) To avoid cavitation related damage. That is what you are interested in

 

2) For Mechanical stability of a pump a min. flow is required.

 

I would suggest you to contact the pump vendor for minimum flow rather than you calculating the same..

 

I would also suggest you put a minimum flow line (with a RO or control valve based on the motor rating) considering the fluid is Ethanol

[raj shekhar]

 

 

Hi,

 

Can we know the reason for calculating the temperature rise?

 

are you calculating the minimum re-circulation flow or something else? 

Hi,

 

The pump is used here for transferring Ethanol, as it's a flammable liquid I wanted to know what is the temp. rise if we dead head the pump for longer time. If the temp. rise is much higher I will go for a minimum re-circulation line.

 

Thank You,

Raj Shekhar Ghosh

 

 

Please note that minimum re-circulation is required for two reason

 

1) To avoid cavitation related damage. That is what you are interested in

 

2) For Mechanical stability of a pump a min. flow is required.

 

I would suggest you to contact the pump vendor for minimum flow rather than you calculating the same..

 

I would also suggest you put a minimum flow line (with a RO or control valve based on the motor rating) considering the fluid is Ethanol

 

Thank you Chemitofreak, for your suggestion.