3 replies to this topic

[hech21]

Dear All,

 

I m dealing with centrifugal pump (6*13 DS-VP).I have  the pum performance curves only for RPM=3000 and Impller diameter=11 1/2".I want to select an RPM for my new operating conditions in order to optimize the elctrical consumption regarding the motor.

I m looking for relationship between RPM and (flowrate,head).

 

Operating condition:

 

    Fluid pumped: Crude oil.

    viscosity@PT: 38 ssu

    Normal capacity: 875 USGPM

    Design capacity: 1250 USGPM

    Diff head: 300 feet.

    NPSHa: 19 feet.

Edited by hech21, 13 May 2015 - 10:45 AM.

[fallah]

Dear All,

 

I m dealing with centrifugal pump (6*13 DS-VP).I have  the pum performance curves only for RPM=3000 and Impller diameter=11 1/2".I want to select an RPM for my new operating conditions in order to optimize the elctrical consumption regarding the motor.

I m looking for relationship between RPM and (flowrate,head).

 

Operating condition:

 

    Fluid pumped: Crude oil.

    viscosity@PT: 38 ssu

    Normal capacity: 875 USGPM

    Design capacity: 1250 USGPM

    Diff head: 300 feet.

    NPSHa: 19 feet.

 

hech21,

 

You can use pump's affinity laws as follows:

 

P₁/P₂=(n₁/n₂)³(d₁/d₂)³

 

dp₁/dp₂=(n₁/n₂)²

 

q₁/q₂=n₁/n₂

 

Where:

 

P=Power

n=Impeller speed; rpm

d=impeller diameter

dp=Head

q=Flow rate

 

1=Initial value

2=Final value

Edited by fallah, 13 May 2015 - 01:02 PM.

[Bobby Strain]

So, how are you going to provide the speed you are seeking?

 

Bobby

[shan]

If you have no VFD (Variable Frequency Drive), you may only recycle portion of discharge flow back to suction side to control pump delivery rate without any power saving.