Fluid Mechanics CFD Analysis of Axial Flow Pumps

This article discusses the importance of CFD in fluid mechanics and its application in axial flow pumps. It covers advantages and disadvantages of CFD over experimental work, numerical simulation procedures for axial flow pumps, and studies on computational fluid dynamics analysis of axial flow pumps.

Fluid mechanics CFD analysis 1
FLUID MECHANICS CFD ANALYSIS
By Name
Course
Instructor
Institution
Location
Date

Fluid mechanics CFD analysis 2
Introduction
The flow of fluids in axial flow pumps is governed by the
partial differential equations which in most cases represents
the conservation laws for energy, momentum and mass. CFD
refers to the art of substituting such partial differential
equations technique with algebraic equations which can be
digitally solved using very fast computers (Ahir, 2015, p.
567).
CFD is a branch of fluid mechanics which uses numerical and
data structures analysis to solve and analyse problems which
involve the flow of fluids. Computers are always used to carry
out the computation which is needed to simulate the
correlation of liquids and gases which have surfaces that are

Fluid mechanics CFD analysis 3
clearly defined by their boundary conditions. By using high
speed supercomputers, it is possible to achieve better
simulations (Alexandrov, 2017, p. 43).
CFD offers a quantitative and qualitative prediction of fluid
flows by applying mathematical modelling, solution
techniques, discretization and software tools such as the pre-
processing utilities, post- processing utilities and solvers
Axial flow pumps are very common types of pumps which in
most cases comprises of the propeller in a pipe. The propeller
is driven by an electric motor or petrol/diesel engines which
are fixed to the tube from outside, sealed motor or a right-
angled drive shaft which cuts the pipe (Badr, 2015, p. 123).
The flow of the fluid particles through the pump don’t change
location because the suction change (entry radius) and the exit
(discharge) of the pump is small thus the term ‘axial’ pump.

Fluid mechanics CFD analysis 4
Most of the axial flow pumps have propellers-type of the
impeller which runs in the casing. The flow of fluids over the
blades of the impeller develops the pressure of the axial flow
pump. The fluid which flows through the pump is moved in
the direction which is parallel to the impeller shaft (fluid
particles) they do not change their radial location when
flowing through the pump. Due to that the fluid is allowed to
enter the propeller axially or axially discharge the fluid. The
axial flow pump propeller is driven by the motor. (Brandt,
2015, p. 289).
Importance of using CFD in different fields.
Application of the CFD has a lot of benefits which are
associated with it such as:
 In the automotive production Computational fluid dynamics
heaps the designers to enhance the aerodynamic
characteristics of the vehicles which they produce.

Fluid mechanics CFD analysis 5
 In architecture, computational fluid mechanics help the
architects to come up with designs which are safe and
comfortable environments to live in.
 For the industrial and chemical engineering it CFD helps
the chemical engineers maximize the output from their
equipment.
 Computation fluid dynamics assists the petroleum
engineers to come up with optimal oil recovery strategies.
 Computational fluid dynamics helps in the prevention of
natural disasters. The meteorologists can be able to use
CFD to warn of the natural disasters through weather
forecasting (Burrows, 2012, p. 675).
 For safety experts, it helps to reduce health risks from
different hazards such radiations.
 Computational fluid dynamics helps the military
personnel’s to estimate the damages which can be caused

Fluid mechanics CFD analysis 6
by different weapons and helps in the development of the
weapons.
 Accuracy: computational fluid dynamics is an approach
which uses the high-speed computers to solve partial
differential equations relating to the flow of fluids. In most
cases, it involves approximations to discretize the
mathematical equations. The applications of CFD in
solving problems which are associated with the flow of
fluids is very accurate since it involves the use of
computers.
 The use of computational fluids is very cost effective: the
only coats which are incurred when carrying out
computational fluids dynamics are only computing costs
and the cost for obtaining a license (Crouse, 2015, p. 76).
 The Computational fluid dynamics is very accessible in that
only that is required for you to carry out computational
fluid dynamics is a computer. The experiment on

Fluid mechanics CFD analysis 7
 The other hands are a very elaborate process. The first
thing which is needed to be done is to design your model
then involve the workshop to assist in fabrications then wait
for tunnel time slots.
Advantages of CFD over experimental work.
It is very fast and reliable in that one can be able to turn
around much faster as compared to experiments. One can be
able to test many models at a go since it involves the use of
computers.
The computational fluid dynamics is almost free since what
one is required to pay for is only the license for the software
as compared to the experiments which will require a lot of
resources to be able to be conducted (Dieguez, 2013, p. 173).
Coding is a very important element or tool which one needs to
know in general. The Computation fluid dynamics will enable
one to obtain the basic understanding of the fluids.

Fluid mechanics CFD analysis 8
Disadvantages of computational fluid dynamics over
experimental work.
For the computational fluid mechanics, not all the models
which are generated are reliable some of the models cannot be
generated which makes this technique to be very unreliable
unlike the experimental methods where the study of the
characteristics of the fluids can be easily carried out (Donald
M. Sandercock, 2016, p. 253).
When carrying out the simulation of very large simulations,
one can require very large and expensive computers which are
very hard to acquire.
Axial-flow pumps.
Axial-flow pumps comprise of a propeller which is confined
within a cylindrical casing which is often referred to as
propeller pump (Ganis, 2013, p. 76). Below is a well labelled

Fluid mechanics CFD analysis 9
schematic diagram of an axial –flow pump arranged for
vertical operations.
Numerical Simulation by use of Computational Fluid
Dynamic for the Axial-Flow Water Pump. To determine
Complex Turbulent flow.
The axial flow pumps are characterised by huge flow rates
and low discharge pressure. Due to those essential features,
the axial flow pumps are widely used in different systems
such as the municipal water supply, Municipal drainage

Fluid mechanics CFD analysis 10
system, water diversion systems, and irrigation systems and
for the major pump for nuclear power plants.
The flow of fluids in axial pumps is very unsteady, complex
and fully three-dimensional turbulent. The turbulent flow
which is complex as the one mentioned above dominates the
characteristics of efficiency, Performance, the vibration of the
pump and noise. Nevertheless, many of the physical
mechanisms and phenomena which are involved have
understood in details up to date, and is considered to be very
crucial in better understanding of the mechanisms and physics
behind the axial flow pump (García, 2018, p. 107).
The flow of fluids is very complex to be determined using the
ordinary experiments because of the pump rotor-stator, which
needs CFD numerical simulation methods. In the previous,
most of the experimental and numerical studies have been
conducted to understand the unsteady flow characteristics

Fluid mechanics CFD analysis 11
inside the axial-flow pumps (Grist, 2011, p. 45). From the
experiments which have been carried out the quantities which
were always the, parameters which mostly include the pump
efficiency and the rate of flow.The diagram below shows the
comparison between different impellers (Grondzik, 2015, p.
76).
Experimental studies on the axial flow pumps.
1. The experiment by Mostafa Zierke
The experimental study which was carefully designed on a
high-Reynolds-number through different measurements

Fluid mechanics CFD analysis 12
methods which include: calibrated five-hole pressure
investigates the determination of stagnation (Badr, 2015, p.
67)
2.0 Measurements of the axial and tangential velocities, by
Boraey
To measure tangible and axial velocities of the pump inlet
guide and the pump vane exit flow. Tip clearance and rotor
blade exist, an oil paint method for visualization of the skin-
friction and neighbouring end walls and the rotor blades
surface. Very successful feedback was obtained in this
experiment by using computational fluid dynamics numerical
(Urasak, 2016, p. 896). To understand the complex turbulent
flows and came up with ways through which it can be
enhanced.
Findings of the experimental studies.

Fluid mechanics CFD analysis 13
It was noted that from the results of the experiments, the
complicated turbulent flow in the experiments that were
carried out was limited. This was attributed to the geometry
flow passage. Hence the computation fluid dynamics has to be
conducted find out the characteristics of the complex turbulent
flow. (Thompson, 2017, p. 182).
The computational fluid dynamics which were carried out by
Boraey and Mostafa used the K-𝜀model to show as evidence
for the effects of turbulent in their calculations of the two-
phased flow field around a 3D impeller in a cavitation pump
by the use of commercial computational fluid dynamics. In
addition to their efforts in carrying out experiments, they used
k-𝜀 model. The effects of the inducer which is the interaction
of the flow via the inducer (Thomas, 2011, p. 25).
Design of axial flow pumps by application of computation
fluid dynamics.

Fluid mechanics CFD analysis 14
Procedures for Numerical Simulations
1. Computational Domain.
The simulation object which was simulated in his case is
the axial flow pump. This is to be carried out with the main
objectives to reduce the effects of the boundary conditions
and to ensure that the appropriate extensions, numerical
stability are perfectly processed at the inlet and the outlet
respectively (Taylor, 2016, p. 162).
2. Mesh generation
For one to be able to simulate the actual flow filed and be
able to determine any of the asymmetrical flow that can be
detected, the whole hydraulic passage of the model-axial
flow pump is taken as the computational domain .when
accounting for the complexity geometry of the pump and
the convince of implementation, from the studies which
have been carried out by many researchers they employed
the unstructured mesh in the investigation the internal flow

Fluid mechanics CFD analysis 15
of the fluids in the axial flow pumps. Nevertheless, the
adoption of the unstructured mesh in thei5 studies led to
more grid quantity. And it is impossible to control the grid
quality (Syed, 2012, p. 87).
Accurately. As it is known, the use of turbulence model
requires specific range of the wall variable𝑦+ = (𝑦⋅𝑢 𝜏/])
(where𝑦 is the wall normal distance of the nearest grid away
from the wall,] is the kinematic viscosity, and𝑢𝜏 =√𝜏𝑤/𝜌 is
the friction velocity with 𝜏𝑤 and 𝜌 being walls hear stress
and fluid density, resp.).
The generation of the structured mesh can greatly help in the
control of the first layer and the density of the mesh exactly
and reduce the grid quantity dramatically as well.
3. Boundary Conditions.
AS the inflow condition, the mass flow rates which are
associated with the target for the simulation are specified.

Fluid mechanics CFD analysis 16
The simulated inlet rate𝑄𝑚 = 305kg/s, head 𝐻=29.5m,
and rotating speed 𝑛=2970rpm (Soltis, 2017, p. 87).
The direction of the absolute velocity vector is axially
imposed at the inlet pipe. The inlet pipe at the upstream of
the impeller is sufficiently long to develop a velocity
profile which is full before the flow enters the impeller.
In practical situations there are non-negligible radial
velocities in the real situation, at the front of the impeller
there are non-negligible radial velocities that are important
for the flow field flow in the impeller. However, due to the
difficulties of setting up realistic turbulent inflow
conditions, only the mass flow rate and the direction of the
velocity are imposed. It is only expected here that the
turbulent flow state can be fully developed by the
interactions of flow with the solid wall (Slater, 2012, p.
721). Hence the development of the turbulent structures
may require an excessive length of the inlet section.

Fluid mechanics CFD analysis 17
A summary of studies on computational fluid dynamics
analysis of axial flow pumps
The aspect of
computational fluid
dynamics analysis of the
Axial flow pumps
Author.
The computational fluid
analysis in the axial flow
pumps viscous flow in the
axial flow pumps impellers.
Different studies which have
been conducted by different
scholars on this topic of the
CFD and its relationship
with the axial fluids has also
been covered well in this
Hirsh and Kang (2001);
Shah et al. (2012)

Fluid mechanics CFD analysis 18
journal.
The characteristic
performance of the axial
pump plus the performance
of the axial flow pump and
the flow patterns of the
impeller. How the
performance of the axial
flow pump can be enhanced
has been greatly discussed
by the author.
Suggestions on how the axial
flow pump can be improved
by use of CFD has been
explained in details (Sharma,
2016, p. 86).
Maratha et al. (20140; li
(2000)

Fluid mechanics CFD analysis 19
The investigation of the
internal flow of the axial
flow pump during the design
point.
The author of the journal
gives different suggestions
on how the Computational
fluid dynamics can be used
to improve the flow of the
fluids in the axial flow pump
before it is being designed
(Serovy, 2014, p. 113).
Akhras (2006)
The computational analysis
of the mixed flow axial
pump impeller.
How the computational fluid
dynamics can be used
Patel (20130; Kush (2007);
Akhtar (2016)

Fluid mechanics CFD analysis 20
accurately to study the
different characteristics of
the impeller has also been
discussed in this journal.
Using the CFD to investigate
the Hydraulic design of the
axial flow pumps.
The different principles
which are behind the design
of the axial flow pumps have
been outlined and the
physics or science behind
them.
Nagahara (2013); Kang
(2014) and Yang(2009)
The prediction of how the
axial flow pump works has
also been outlined in this
journal, and the author tries
Dickens chat (2012); Patel
2014

Fluid mechanics CFD analysis 21
to predict how different
types of the axial flow
pumps (Sayigh, 2015, p. 45).
The analysis of the
performance of the axial
flow pump impeller by using
the Computational fluid
dynamics and the
suggestions on how the
performance can be
enhanced by using the CFD
has also been clearly
discussed in this journal/.
Patel and Mehta (2013)
The analysis of the turbulent
flow in the impeller of the
axial flow pump.
Yang (2007)

Fluid mechanics CFD analysis 22
The different types of how
the fluids flow through the
axial flow pump have also
been covered in this journal.
The causes of the stagnation
and change of pressure have
also been covered into
details (Sabau, 2012, p. 342).
Validation and optimization
for the axial flow pump.
The author of this article
tries to explain how the axial
flow pump can be optimized
to obtain high performance
of the axial flow pump.
Prasad (2009)
Computational fluid
dynamics based flow

Fluid mechanics CFD analysis 23
analysis of the axial flow
pumps.
In this article the process on
how the CFD can be used to
analyse the flow of fluids in
the axial flow pump.
Different practices which
have been carried out by
different scholars are
discussed in this book.
The advantages of CFD over
the experimental techniques
are also discussed.
Shah (2015)
Reliability and performance
enhancement in the
manufacture and design of
the axial flow pumps.
Bagi and Kadam (2011)

Fluid mechanics CFD analysis 24
The author of this book
explains the different ways
on how the performance and
reliability of the axial flow
pumps can be enhanced by
the use of computational
fluid dynamics (Miller,
2013, p. 67).
The numerical analysis of
the axial flow pump
performance characteristics.
In this book, the author has
tried to explain how the
numerical analysis can be
used to determine the
characteristic performance of
the axial flow pumps.
Maratha (2015)

Fluid mechanics CFD analysis 25
Numerical study of the axial
flow pumps impeller with
the 2D –curved blades.
The author of this journals
explains the different studies
which have been carried out
successfully but various
scholars on the topic of the
CFD analysis and their
relation to the axial flow
pump (Jones, 2010, p. 65).
Kush and Tracy (2007)
Design optimization of the
axial flow pumps and the
volume by the application of
the computational fluid
mechanisms.
Kim et al. (2014)
The simulation of the

Fluid mechanics CFD analysis 26
unsteady flow of the fluids in
the axial flow pumps has
been discussed in details in
this book.
The author outlines the
major causes of the steady
flow of fluids in the axial
flow pump and gives
suggestions on how the
computational fluid
dynamics can be used to
improve the situation.
Yuliang (2012
Study of the computational
dynamics parametric of the
geometric variations on the
pressure and the
characteristic performance of
Patel (2011)

Fluid mechanics CFD analysis 27
the Axial flow pumps.
The analysis of the turbulent
flow in the impeller of the
axial flow pump.
The different types of how
the fluids flow through the
axial flow pump have also
been covered in this journal.
The causes of the stagnation
and change of pressure have
also been covered into
details.
Maratha ( 2009)
Computational fluid
dynamics based flow
analysis of the axial flow
pumps.
In this article the process on
Maratha (2015)

Fluid mechanics CFD analysis 28
how the CFD can be used to
analyse the flow of fluids in
the axial flow pump.
Different practices which
have been carried out by
different scholars are
discussed in this book.
The advantages of CFD over
the experimental techniques
are also discussed.
Conclusion.
In conclusion, the computational fluid dynamics plays a very
important role in the design of the axial flow pumps. It is
much easier to study different components of the axial flow
pumps.

Fluid mechanics CFD analysis 29
CFD is a branch of fluid mechanics which uses numerical and
data structures analysis to solve and analyse problems which
involve the flow of fluids. Computers are always used to carry
out the computation which is needed to simulate the
correlation of liquids and gases which have surfaces that are
clearly defined by their boundary conditions. By using high
speed supercomputers, it is possible to achieve better
simulations
It is much accurate to study the designs and operations of the
axial-flow pumps by the use of the computational fluid
The axial flow pumps are characterised by huge flow rates
and low discharge pressure. Due to those essential features,
the axial flow pumps are widely used in different systems
such as the municipal water supply, Municipal drainage
system, water diversion systems, and irrigation systems and
for the major pump for nuclear power plants.

Fluid mechanics CFD analysis 30
There are many benefits which are associated with
computational fluid dynamics such as;
Accuracy, computational fluid dynamics is an approach which
uses the high-speed computers to solve partial differential
equations relating to the flow of fluids.in most cases it
involves approximations to discretize the mathematical
equations. The applications of CFD in solving problems
which are associated with the flow of fluids is very accurate
since it involves the use of computers (Kováts, 2014, p. 175).
The use of computational fluids is very cost effective: the only
coats which are incurred when carrying out computational
fluids dynamics are only computing costs and the cost of
obtaining a license.
The Computational fluid dynamics is very accessible in that
only that is required for you to carry out computational fluid
dynamics is a computer. The experiment on

Fluid mechanics CFD analysis 31
The other hands are a very elaborate process. The first thing
which is needed to be done is to design your model then
involve the workshop to assist in fabrications then wait for
tunnel time slots.
Disadvantages of computational fluid dynamics over
experimental work include:For the computational fluid
mechanics, not all the models which are generated are reliable
some of the models cannot be generated which makes this
technique to be very unreliable unlike the experimental
methods where the study of the characteristics of the fluids
can be easily carried out (Donald M. Sandercock, 2016, p.
253).
When carrying out the simulation of very large simulations,
one can require very large and expensive computers which are
very hard to acquire.

Fluid mechanics CFD analysis 32
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Fluid mechanics CFD analysis 33
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Fluid mechanics CFD analysis 35
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Fluid mechanics CFD analysis 36
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Fluid mechanics CFD analysis 39