PACIFIC SCHOOL OF ENGINEERING
Advancement of Pump
GUIDE BY:
Mr. H.M.JARIWALA
NAME
PATEL RAJ
PATEL JAYDIP
PATEL PARTH
PATEL NIKUNJ
RANA KARAN
ENROLLMENT NO.
131120105039
131120105035
131120105038
131120105037
131120105046
Theoretical Head Developed by an Impeller
Principles of an Centrifugal Pump
•
ESPs are multi stage centrifugal pumps.
•
The two main components of a centrifugal pump are the impeller and the
diffuser.
•
The Impeller takes the power from the rotating shaft and accelerates the fluid.
•
The diffuser transforms the high fluid velocity into pressure
Theoretical Head Developed by an Impeller
Geometry of an Centrifugal Pump
•
The main components of an ESP including:
Impellers
Casing
Diffusers
Shaft
Thrust washers
Bushing
Impeller
Washer
Diffuser
Theoretical Head Developed by an Impeller
Geometry of an Centrifugal Pump
Impeller
diffuser
Theoretical Head Developed by an Impeller
Assumptions
•
Assumptions:
1. Two dimensions: radial and tangential direction.
2. The impeller passages are completely filled with the flowing fluid at all time (no
void spaces)
3. The streamlines have a shape similar to the blade’s shape
4. Incompressible, inviscid, and single phase fluid
5. The velocity profile is sysmetric.
•
The head calculated based on these assumptions is known as the theoretical
head
Theoretical Head Developed by an Impeller
Velocity at One Point on the Impeller’s Blade
Theoretical Head Developed by an Impeller
Conclusion on Triangle Fluid Velocity
•
operational parameters:
•
1. Angle, b: knowing pump blade geometry
•
2. Tangential velocity, U knowing the rotational speed
•
3. Radial velocity, vr: knowing the flow rate.
•
Therefore, the velocity triangle is completely determined.
•
What we need now is to find the pressure increment developed by one impeller
as a function of those operational parameters and last one, namely the fluid
density
Theoretical Head Developed by an Impeller
Based on a Free Body Diagram
r
R + dr
Theoretical Head Developed by an Impeller
Based on a Free Body Diagram
Theoretical Head Developed by an Impeller
Based on a Free Body Diagram
Theoretical Head Developed by an Impeller
Based on a Free Body Diagram
Theoretical Head Developed by an Impeller
Based on a Free Body Diagram
Theoretical Head Developed by an Impeller
Mass Balance
•
Mass balance equation under steady state conditions in cylindrical coordinate:
•
NOTE: that the fluid at the outlet of the impeller has two components: vr and vq.
However, the change of vq respect to q is zero.
•
•
Hence:
constant
Theoretical Head Developed by an Impeller
Mass Balance
•
•
The flow rate entering the pump intake is given (ri = r):
or
•
Rotational speed is related to the tangential velocity U by:
•
Hence, we know three parameters:
Theoretical Head Developed by an Impeller
Mass Balance
•
Three parameters:
•
Combining with the triangle velocity gives:
Theoretical Head Developed by an Impeller
Pump Head Definition
•
Definition for the pump head:
•
Head is an indirect measurement of pressure that does not depend on the fluid
density.
•
That means for low viscous fluids, the pump performance can b uniquely defined
in terms of head.
•
, the pump performance, in pressure, depends on the density of the fluid being
pumped, but when this performance is expressed in head, the pump
performance is independent of the fluid being pumped
Theoretical Head Developed by an Impeller
Pump Head Definition
Theoretical Head Developed by an Impeller
Head Losses
•
Due to the Leakage and recirculation of fluid inside the impeller.
•
Hydraulic losses including:
•
Diffusion loss due to divergence, or convergence
•
Fluid shock loss at the inlet
•
Mixing and eddying loss at the impeller discharge
•
Turning
loss
due
Separation losses
•
Friction losses
•
Mechanical losses
to
turning
of
the
absolute
velocity
vector
Theoretical Head Developed by an Impeller
Hydraulic Losses
•
Pumps are designed trying to achieve a no pre-rotation condition close to the
best efficiency point, since this condition minimize shock-losses. In other words,
shock losses increase as we move away from the BEP.
Theoretical Head Developed by an Impeller
Hydraulic Losses
Other losses including friction, mixing, change in direction of fluid, separation,
etc. also contribute significantly to the total losses due to hydraulic.
Theoretical head (Euler head)
Hydraulic losses
Head, H
•
Flow rate, Q
THANK YOU