This document provides information about centrifugal pumps, including:
1. It defines a centrifugal pump and describes its main components like the impeller, volute casing, and diffuser.
2. It explains how volutes and diffusers function to convert velocity energy to pressure energy and reduce turbulence respectively.
3. It discusses the basic theory and operation of centrifugal pumps, including velocity triangles, impeller head development, and the effects of varying parameters like flow, speed, and impeller diameter.
4. It covers topics like cavitation, viscosity effects, pump performance curves, operating conditions, efficiency, and the use of similarity principles to predict pump performance.
Energy Savings with Variable Frequency DrivesAzizah Kassim
To understand what is VFD / VSD / ASD / Inverter and what does it do.
To understand what is System Curve, Pump & Fan Curve and also Affinity Law
To understand how VFD saves AC motor ‘s energy
To estimate energy savings by using VFD to control speed of motor driving pumps / fans
To demonstrate few VFD’s applications in building and how it can save the energy
Pumps are used in virtually all industries and are big uses of energy. This presentation shows methods of condition monitoring and how to optimise time to overhaul.
Southern Methodist UniversityBobby B. Lyle School of Engineeri.docxwhitneyleman54422
Southern Methodist University
Bobby B. Lyle School of Engineering
CEE 2342/ME 2342 Fluid Mechanics
Roger O. Dickey, Ph.D., P.E.
V. STEADY PIPE FLOW
D. Pump Selection
Reading Assignment:
Chapter 12 Turbomachines
Section 12.4 – The Centrifugal Pump, pp. 687-700
E. Pump Selection
Pump Applications –
Pumps are used in a wide array of engineering applications including:
Low-lift pumps high-volume, low-head pumps used to elevate fluids, e.g., elevating water from a supply source to a water treatment plant or wastewater from a gravity sewer to a wastewater treatment plant.
High-service pumps used to deliver fluids under “adequate” pressure throughout a distribution piping network, or through long transmission pipelines.
Booster pumps used to increase fluid pressure at intermediate points along transmission pipelines, or within distribution piping networks.
Recirculation and transfer pumps used to convey fluids for one unit operation or process to another within an engineered system or facility.
Well pumps used to lift water from ground water aquifers for water supply purposes.
Chemical metering pumps used to deliver reagent chemicals at precisely controlled rates to chemical processes.
Fire pumps used for delivering high flow rates at high pressures for firefighting.
Sludge pumps used to convey thick slurries from one unit operation or process to another within an engineered system or facility.
Sampling pumps used in both portable and fixed equipment designed to collect precise sample volumes over precise time intervals within engineered systems or facilities.
Pump Types -
Pumps can be broadly classified as either,
Dynamic
Positive displacement
Dynamic pumps deliver flow rates that vary as a function of the discharge head on the pump.
Conversely, positive displacement pumps deliver flow rates that remain relatively constant, regardless of changes in the discharge head.
Dynamic pumps can be further subdivided into classes,
Centrifugal – axial flow, radial flow, mixed flow, and peripheral flow pumps
Special effect – including eductor (or jet), ejector, and air lift pumps
10
Positive displacement pumps can be further subdivided into classes,
Reciprocating – piston (or plunger) and diaphragm pumps
Rotary – including gear, lobe, screw, progressing cavity, vane, and peristaltic (or tubing) pumps
11
Centrifugal pumps are the most widely used type in engineering applications including:
Low-lift – Vertical Turbine
Axial Flow
Archimedes Screw
High-service – Split-case, double suction centrifugal
Vertical-turbine Pump
Axial Flow (Vertical Propeller) Pump
Archimedes Screw Pumps
Split-case, Double-suction Centrifugal Pump
Booster
Recirculation and transfer
Well – down-hole pumps
Firefighting
Figure 12.6 – Schematic of Basic Elements of Centrifugal Pumps
Centrifugal Pumps
Submersible
Vertical Sump Pump
Horizontal
Fire Pump System, Internal Combustion Driver
Ce.
Energy Savings with Variable Frequency DrivesAzizah Kassim
To understand what is VFD / VSD / ASD / Inverter and what does it do.
To understand what is System Curve, Pump & Fan Curve and also Affinity Law
To understand how VFD saves AC motor ‘s energy
To estimate energy savings by using VFD to control speed of motor driving pumps / fans
To demonstrate few VFD’s applications in building and how it can save the energy
Pumps are used in virtually all industries and are big uses of energy. This presentation shows methods of condition monitoring and how to optimise time to overhaul.
Southern Methodist UniversityBobby B. Lyle School of Engineeri.docxwhitneyleman54422
Southern Methodist University
Bobby B. Lyle School of Engineering
CEE 2342/ME 2342 Fluid Mechanics
Roger O. Dickey, Ph.D., P.E.
V. STEADY PIPE FLOW
D. Pump Selection
Reading Assignment:
Chapter 12 Turbomachines
Section 12.4 – The Centrifugal Pump, pp. 687-700
E. Pump Selection
Pump Applications –
Pumps are used in a wide array of engineering applications including:
Low-lift pumps high-volume, low-head pumps used to elevate fluids, e.g., elevating water from a supply source to a water treatment plant or wastewater from a gravity sewer to a wastewater treatment plant.
High-service pumps used to deliver fluids under “adequate” pressure throughout a distribution piping network, or through long transmission pipelines.
Booster pumps used to increase fluid pressure at intermediate points along transmission pipelines, or within distribution piping networks.
Recirculation and transfer pumps used to convey fluids for one unit operation or process to another within an engineered system or facility.
Well pumps used to lift water from ground water aquifers for water supply purposes.
Chemical metering pumps used to deliver reagent chemicals at precisely controlled rates to chemical processes.
Fire pumps used for delivering high flow rates at high pressures for firefighting.
Sludge pumps used to convey thick slurries from one unit operation or process to another within an engineered system or facility.
Sampling pumps used in both portable and fixed equipment designed to collect precise sample volumes over precise time intervals within engineered systems or facilities.
Pump Types -
Pumps can be broadly classified as either,
Dynamic
Positive displacement
Dynamic pumps deliver flow rates that vary as a function of the discharge head on the pump.
Conversely, positive displacement pumps deliver flow rates that remain relatively constant, regardless of changes in the discharge head.
Dynamic pumps can be further subdivided into classes,
Centrifugal – axial flow, radial flow, mixed flow, and peripheral flow pumps
Special effect – including eductor (or jet), ejector, and air lift pumps
10
Positive displacement pumps can be further subdivided into classes,
Reciprocating – piston (or plunger) and diaphragm pumps
Rotary – including gear, lobe, screw, progressing cavity, vane, and peristaltic (or tubing) pumps
11
Centrifugal pumps are the most widely used type in engineering applications including:
Low-lift – Vertical Turbine
Axial Flow
Archimedes Screw
High-service – Split-case, double suction centrifugal
Vertical-turbine Pump
Axial Flow (Vertical Propeller) Pump
Archimedes Screw Pumps
Split-case, Double-suction Centrifugal Pump
Booster
Recirculation and transfer
Well – down-hole pumps
Firefighting
Figure 12.6 – Schematic of Basic Elements of Centrifugal Pumps
Centrifugal Pumps
Submersible
Vertical Sump Pump
Horizontal
Fire Pump System, Internal Combustion Driver
Ce.
Guide to the selection of UNIQA electric pumps - Zenit GroupZenit Group
The introduction of UNIQA® pumps requires sales technicians and resellers to be able to select and ex-plain their constructional and functional characteristics. They must therefore be familiar with the basic technical concepts applicable to all pumps, as well as those which apply specifically to the UNIQA® range:
- Basic concepts of hydraulics
- Q-H curve (duty point)
- Pump - Motor (P1 - P2 - P3)
- Efficiency
- Concept of hydraulics
- Applying motors of various power ratings to a given impeller
- Operation with frequency variator
- Other selection criteria (materials, versions, etc.)
Design Considerations for Antisurge Valve SizingVijay Sarathy
Centrifugal Compressors experience a phenomenon called “Surge” which can be defined as a situation where a flow reversal from the discharge side back into the compressor casing causing mechanical damage.
The reasons are multitude ranging from driver failure, power failure, upset process conditions, start up, shutdown, failure of anti-surge mechanisms, check valve failure to operator error to name a few. The consequences of surge are more mechanical in nature whereby ball bearings, seals, thrust bearing, collar shafts, impellers wear out and sometimes depending on the how powerful are the surge forces, cause fractures to the machinery parts due to excessive vibrations.
The following tutorial explains how to size an anti-surge valve for a single stage VSD system for Concept/Basic Engineering purposes.
The aim of this project is to design a positive displacement rotary pump for small scale applications. The design is in such a way that it combines the advantages of both rotodynamic and positive displacement pumps. Currently available centrifugal pumps cannot attain high heads, and reciprocating pumps are less efficient and requires much space. When centrifugal pump is used as a jet pump, it delivers fluids at a high head, but in the expense of efficiency.
To overcome these negatives of currently available pumps, a new design of a rotary type positive displacement pump is developed. This design imitates the working of a normal reciprocating pump, but in a rotary action. This consumes less space compared to a reciprocating pump of same capacity. The main part of the pump is a cam which is mounted on a rotating shaft that rotates in a cylindrical casing. The cam is designed in such a way that it always maintains contact with the walls of the casing as it rotates. A spring loaded blade acts as the cam follower and moves in an accurately machined slot in the casing. The blade and the slot are of rectangular cross section. This blade separates suction and delivery sides of the pump. Inlet and outlet ports are placed on either sides of this blade. This pump does not require inlet and outlet valves. The discharge from the pump is continuous. It also eliminates the crank and connecting-rod mechanisms and delivers a smooth operation.
The air-standard cycle is an idealized cycle founded on the following approximations: (1) The working fluid throughout the cycle is only air; (2) the air acts as an ideal gas; (3) combustion processes are replaced by well-defined heat addition processes; and (4) the exhaust process is replaced by a heat rejection ...
Generally Pumps classification done on the basis of its mechanical configurat...ShriPrakash33
Pumps simplify the transportation of water and other fluids, making them very useful in all types of buildings - residential, commercial, and industrial. For example, fire pumps provide a pressurized water supply for firefighters and automatic sprinklers, water booster pumps deliver potable water to upper floors in tall buildings, and hydronic pumps are used in HVAC systems that use water to deliver space heating and cooling.
TYPES OF PUMPS AND THEIR WORKING PRINCIPLES
Generally Pumps classification done on the basis of its mechanical configuration and their working principle. Classification of pumps mainly divided into two major categories:
Dynamic pumps / Kinetic pumps
Dynamic pumps impart velocity and pressure to the fluid as it moves past or through the pump impeller and, subsequently, convert some of that velocity into additional pressure. It is also called Kinetic pumps Kinetic pumps are subdivided into two major groups and they are centrifugal pumps and positive displacement pumps.
Classification of Dynamic Pumps
1.1 Centrifugal Pumps
A centrifugal pump is a rotating machine in which flow and pressure are generated dynamically. The energy changes occur by virtue of two main parts of the pump, the impeller and the volute or casing. The function of the casing is to collect the liquid discharged by the impeller and to convert some of the kinetic (velocity) energy into pressure energy.
1.2 Vertical Pumps
Vertical pumps were originally developed for well pumping. The bore size of the well limits the outside diameter of the pump and so controls the overall pump design.2.) Displacement Pumps / Positive displacement pumps
2. Displacement Pumps / Positive displacement pumps
Positive displacement pumps, the moving element (piston, plunger, rotor, lobe, or gear) displaces the liquid from the pump casing (or cylinder) and, at the same time, raises the pressure of the liquid. So displacement pump does not develop pressure; it only produces a flow of fluid.
Classification of Displacement Pumps
2.1 Reciprocating pumps
In a reciprocating pump, a piston or plunger moves up and down. During the suction stroke, the pump cylinder fills with fresh liquid, and the discharge stroke displaces it through a check valve into the discharge line. Reciprocating pumps can develop very high pressures. Plunger, piston and diaphragm pumps are under these type of pumps.
2.2 Rotary Type Pumps
The pump rotor of rotary pumps displaces the liquid either by rotating or by a rotating and orbiting motion. The rotary pump mechanisms consisting of a casing with closely fitted cams, lobes, or vanes, that provide a means for conveying a fluid. Vane, gear, and lobe pumps are positive displacement rotary pumps.
2.3 Pneumatic Pumps
Compressed air is used to move the liquid in pneumatic pumps. In pneumatic ejectors, compressed air displaces the liquid from a gravity-fed pressure vessel through a check valve into the discharge line in a series of surges spaced by the time required.
Energy conservation related to pumps used in thermal power stationsManohar Tatwawadi
The presentation discusses about the conservation of energy in pumps and pumping stations as whole in Thermal Power Stations.The pumps efficiency is also discussed in details, how to calculate and the steps to increase efficiency of pumps as well as pumping stations.
Cavitation Effects in Centrifugal Pumps- A ReviewIJERA Editor
Cavitation is one of the most challenging fluid flow abnormalities leading to detrimental effects on both the
centrifugal pump flow behaviors and physical characteristics. Centrifugal pumps’ most low pressure zones are the
first cavitation victims, where cavitation manifests itself in form of pitting on the pump internal solid walls,
accompanied by noise and vibration, all leading to the pump hydraulic performance degradation. In the present
article, a general description of centrifugal pump performance and related parameters is presented. Based on the
literature survey, some light were shed on fundamental cavitation features; where different aspects relating to
cavitation in centrifugal pumps were briefly discussed.
Guide to the selection of UNIQA electric pumps - Zenit GroupZenit Group
The introduction of UNIQA® pumps requires sales technicians and resellers to be able to select and ex-plain their constructional and functional characteristics. They must therefore be familiar with the basic technical concepts applicable to all pumps, as well as those which apply specifically to the UNIQA® range:
- Basic concepts of hydraulics
- Q-H curve (duty point)
- Pump - Motor (P1 - P2 - P3)
- Efficiency
- Concept of hydraulics
- Applying motors of various power ratings to a given impeller
- Operation with frequency variator
- Other selection criteria (materials, versions, etc.)
Design Considerations for Antisurge Valve SizingVijay Sarathy
Centrifugal Compressors experience a phenomenon called “Surge” which can be defined as a situation where a flow reversal from the discharge side back into the compressor casing causing mechanical damage.
The reasons are multitude ranging from driver failure, power failure, upset process conditions, start up, shutdown, failure of anti-surge mechanisms, check valve failure to operator error to name a few. The consequences of surge are more mechanical in nature whereby ball bearings, seals, thrust bearing, collar shafts, impellers wear out and sometimes depending on the how powerful are the surge forces, cause fractures to the machinery parts due to excessive vibrations.
The following tutorial explains how to size an anti-surge valve for a single stage VSD system for Concept/Basic Engineering purposes.
The aim of this project is to design a positive displacement rotary pump for small scale applications. The design is in such a way that it combines the advantages of both rotodynamic and positive displacement pumps. Currently available centrifugal pumps cannot attain high heads, and reciprocating pumps are less efficient and requires much space. When centrifugal pump is used as a jet pump, it delivers fluids at a high head, but in the expense of efficiency.
To overcome these negatives of currently available pumps, a new design of a rotary type positive displacement pump is developed. This design imitates the working of a normal reciprocating pump, but in a rotary action. This consumes less space compared to a reciprocating pump of same capacity. The main part of the pump is a cam which is mounted on a rotating shaft that rotates in a cylindrical casing. The cam is designed in such a way that it always maintains contact with the walls of the casing as it rotates. A spring loaded blade acts as the cam follower and moves in an accurately machined slot in the casing. The blade and the slot are of rectangular cross section. This blade separates suction and delivery sides of the pump. Inlet and outlet ports are placed on either sides of this blade. This pump does not require inlet and outlet valves. The discharge from the pump is continuous. It also eliminates the crank and connecting-rod mechanisms and delivers a smooth operation.
The air-standard cycle is an idealized cycle founded on the following approximations: (1) The working fluid throughout the cycle is only air; (2) the air acts as an ideal gas; (3) combustion processes are replaced by well-defined heat addition processes; and (4) the exhaust process is replaced by a heat rejection ...
Generally Pumps classification done on the basis of its mechanical configurat...ShriPrakash33
Pumps simplify the transportation of water and other fluids, making them very useful in all types of buildings - residential, commercial, and industrial. For example, fire pumps provide a pressurized water supply for firefighters and automatic sprinklers, water booster pumps deliver potable water to upper floors in tall buildings, and hydronic pumps are used in HVAC systems that use water to deliver space heating and cooling.
TYPES OF PUMPS AND THEIR WORKING PRINCIPLES
Generally Pumps classification done on the basis of its mechanical configuration and their working principle. Classification of pumps mainly divided into two major categories:
Dynamic pumps / Kinetic pumps
Dynamic pumps impart velocity and pressure to the fluid as it moves past or through the pump impeller and, subsequently, convert some of that velocity into additional pressure. It is also called Kinetic pumps Kinetic pumps are subdivided into two major groups and they are centrifugal pumps and positive displacement pumps.
Classification of Dynamic Pumps
1.1 Centrifugal Pumps
A centrifugal pump is a rotating machine in which flow and pressure are generated dynamically. The energy changes occur by virtue of two main parts of the pump, the impeller and the volute or casing. The function of the casing is to collect the liquid discharged by the impeller and to convert some of the kinetic (velocity) energy into pressure energy.
1.2 Vertical Pumps
Vertical pumps were originally developed for well pumping. The bore size of the well limits the outside diameter of the pump and so controls the overall pump design.2.) Displacement Pumps / Positive displacement pumps
2. Displacement Pumps / Positive displacement pumps
Positive displacement pumps, the moving element (piston, plunger, rotor, lobe, or gear) displaces the liquid from the pump casing (or cylinder) and, at the same time, raises the pressure of the liquid. So displacement pump does not develop pressure; it only produces a flow of fluid.
Classification of Displacement Pumps
2.1 Reciprocating pumps
In a reciprocating pump, a piston or plunger moves up and down. During the suction stroke, the pump cylinder fills with fresh liquid, and the discharge stroke displaces it through a check valve into the discharge line. Reciprocating pumps can develop very high pressures. Plunger, piston and diaphragm pumps are under these type of pumps.
2.2 Rotary Type Pumps
The pump rotor of rotary pumps displaces the liquid either by rotating or by a rotating and orbiting motion. The rotary pump mechanisms consisting of a casing with closely fitted cams, lobes, or vanes, that provide a means for conveying a fluid. Vane, gear, and lobe pumps are positive displacement rotary pumps.
2.3 Pneumatic Pumps
Compressed air is used to move the liquid in pneumatic pumps. In pneumatic ejectors, compressed air displaces the liquid from a gravity-fed pressure vessel through a check valve into the discharge line in a series of surges spaced by the time required.
Energy conservation related to pumps used in thermal power stationsManohar Tatwawadi
The presentation discusses about the conservation of energy in pumps and pumping stations as whole in Thermal Power Stations.The pumps efficiency is also discussed in details, how to calculate and the steps to increase efficiency of pumps as well as pumping stations.
Cavitation Effects in Centrifugal Pumps- A ReviewIJERA Editor
Cavitation is one of the most challenging fluid flow abnormalities leading to detrimental effects on both the
centrifugal pump flow behaviors and physical characteristics. Centrifugal pumps’ most low pressure zones are the
first cavitation victims, where cavitation manifests itself in form of pitting on the pump internal solid walls,
accompanied by noise and vibration, all leading to the pump hydraulic performance degradation. In the present
article, a general description of centrifugal pump performance and related parameters is presented. Based on the
literature survey, some light were shed on fundamental cavitation features; where different aspects relating to
cavitation in centrifugal pumps were briefly discussed.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
7. Centrifugal Pumps
Definition:
Centrifugal pumps increase
momentum and pressure
head by means of
rotating blades which
converts radial velocity
into pressure head.
Components
– Inlet duct
– Impeller
– Volute
– Discharge nozzle
Centrifugal Action of C.P. Impeller
8. impeller tangential
Velocity due to rotation)
Relative Velocity of
liquid
Velocity of liquid
Resultant
Diffuser
42
Impeller velocity diagrams
9. Velocity Triangles of liquid
due to impeller rotation
43
ν
Vr
U
γ
V
Y
Outlet Vel. Triangle
Vr1
ν1
U1
V1
Y1
1
1
1 B
D
Y
DB
Y
Q
=
=
60
DN
v
=
β
10. 44
To develop the basic theory of centrifugal pump, it is
assumed that :
The impeller consists of infinite number of uniform smooth
vanes of zero thickness. Using the following symbols:
T= torque on impeller shaft.
= angular velocity of impeller.
H = Ideal head developed by pump impeller.
γ= is the outlet blade angle made by the relative velocity
vector with v.
= is theinlet blade angle made by the relative velocity
vector with v1.
r = radius, B = width of flow passage
Theory of centrifugal pump impeller
11. 45
Newton‘s 2nd law stated that; the torque
=the rate of change of angular momentum.
i.e. T = d[mV r]/dt
T= m´[ V .r – V1 .r1]
T = Q [ V .r – V1.r1]
V is the liquids velocity component in tangential direction,
i.e. perpendicular to the radius( Whirl Component).
W.D./unit wt =Tω/ gQ=
ω[ V . R – V1.r1]/g= (V v -V1v1)/g
For Maximum W.D./unit wt , V1=0 i.e. radial flow at inlet.
and the Maximum W.D./unit wt = V . v /g
12. Impeller head
Neglecting Whirl velocity component at inlet ,radial
inlet flow,v1=0
• W.D. on liquid=Eo-Ei;
• Vv/g= U2/2g+ Himp -U1
2/2g (Neglect U1
2/2g )
• U2 =v2+y2 =(v-yCot γ)2 +y2
• Himp.=(v2-y2 Cosec 2 γ)/2g
• With v=πDN/60 & Y=Q/(πDB)=flow vel.
• then Himp.=C1N2-C2Q2
• &H casing=k U2/2g
• H pump=H imp + H casing- Hydraulic Loss in both
46
14. 48
OTHER LOSSES:
•Volumetric – leakage through internal and external clearances
•Mechanical losses: disk friction, bearings, coupling.
The sum of ALL losses takes away from the available power
delivered by the driver:
Σlosses = Hydraulic + Volumetric + Mechanical
Pump Overall efficiency is:
ηoverall = wQHm / Psh
15. 49
internal leakage in C.P.
The leakage loss, for the purposes of obtaining a numerical
estimate, may be regarded as: QL = CLaL(2gHL)0.5
17. • Speed ratio
Flow ratio:
Specific Speed (S.I. units)
Design Key of Hydraulic
Machines
Hydraulic , Manometric
Efficiency :
Pump overall Efficiency:
51
sh
m
Overall
pump
m
Manometric
Hy
o
s
P
wQH
Vv
gH
H
P
N
N
gH
DB
Q
Y
gH
DN
v
=
=
=
=
=
=
=
,
.,
25
.
1
2
,
2
60
23. Recommended Operating range: 60-120% of Q Bep
Excessive Noise & vibrations at lower flows
Cavitation expected at higher flows
57
60%QBep 120%QBep
Recom. Range
Shaft power
Shaft
power
kW
29. • From Diagram at operating point (Qmax.)
• Psh =For delivery partially opened
• Hlv= Hpump- Hpipe
• Psh lv =wQH lv /ηpump
• Energy waste in valve =
• Psh lv . Working hrs/year ; kWhr.
• Delivery valve wastes energy when used to control
flow = excess running cost.
• Cost of total Energy consumed in pump =
ρ.g.Q.Hm T (hrs)* Cost of kWhr/(ηpump. η
motor
)
63
35. Similarity of Pumps
• Complete test on large pumps before installation
is costly, time consuming and also difficult as the
head , flow rate and shaft power cannot be varied
easily, especially at the design stage
• Tests on a geometrically similar model size under
all possible conditions in addition to the
Similarity relations obtained by applying
Buckingham π theory of dimensional analysis ,
the Performance of large size pumps and/or at
different speeds can be predicted.
69
36. Application of π theory in Pumps to
get Similarity relations
• 1-Define the problem and- write the variables
dimensions in terms of M,L,T as;
70
D=L, N=1/T, Q=L3/T, gH=L2/T2,
ρ=M/ L3, μ=M /LT, ε=L
2- Collect these variables in π groups using Buckingham theory of
dimensional analysis as;
π1 =gH/ N2 D2 ,π2= Q/ND3 ,,
π3= ρ ND2/ μ , π4= ε/D or
, gH/ N2D2 =Function of (Q/ND3, ρ ND2/ μ, ε/D)
37. Experience indicated that:
gH/ N2D2 =Function of (Q/ND3)
For geometrically similar pumps under dynamic
similar conditions;
• (Q/ND3 )model = (Q/ND3 ) pump ,
• (gH/ N2D2 )model = (gH/ N2D2 ) pump
• Scale Effect ε/D )model> ε/D ) pump, then ηp> ηm use
empirical formula to get ηp as;
• Moody formula
• Ackerat formula
71
2
.
0
1
1
=
−
−
Dp
Dm
m
p
1
.
0
2
.
0
1
2
1
1
1
+
=
−
−
Hp
Hm
Dp
Dm
m
p
38. Affinity Law
Pump Speed Variation
• For the same pump under dynamically similar
conditions ,substitute D=Constant, in the
previous formulas, ( constant efficiency)
•
• with η1= η2
• These relations can be used to obtain the
performance curves of C.P. at any speed when
they are known at certain speed.
72
3
1
2
1
2
1
2
1
2
P
P
H
H
Q
Q
N
N
=
=
=
39. Centrifugal Pump Characteristics
Flow Q m3/h
Total
Head
H
m
Pump Characteristic
System Characteristic
Normal Flow
Reduced Requirement
Efficiency
η
%
Throttling
Reduced Speed
40. 74
Table 10.1 Power Requirements for Constant- and Variable-Speed Drive Pumps
41. 75
Fig.10.25 : Mean duty cycle for centrifugal pumps in the
chemical and petroleum industries [18].
42. Example : ENERGY SAVINGS WITH VARIABLE-SPEED
CENTRIFUGAL PUMP DRIVE
• Combine the information on mean duty cycle for centrifugal pumps given
in Fig. 10.25 with the drive data in Table 10.1. Estimate the annual savings
in pumping energy and cost that could be achieved by implementing a
variable-speed drive system.
• Given: Consider the variable-flow, variable-pressure pumping system of
Table 10.1. Assume the system operates on the typical duty cycle shown in
Fig. 10.25, 24 hours per day, year round.
• Find: (a) An estimate of the reduction in annual energy usage obtained
with the variable-speed drive.
• (b) The energy costs and the cost saving due to variable-speed operation.
• Solution: Full-time operation involves 365 days X 24 hours per day, or
8760 hours per year. Thus the percentages in Fig. 10.27 may be multiplied
by 8760 to give annual hours of operation.
• First plot the pump input power versus flow rate using data from Table
10.1 to allow interpolation, as shown below
76
45. 79
Summing the last column of the table shows that for the variable-speed drive system,
the annual energy consumption is 3.94X105 hp.hr. The electrical energy consumption is
At $0.12 per kilowatt hour, the energy cost for the variable-speed drive system is only
Thus, in this application, the variable-speed drive reduces energy consumption by 278,000
kWhr (47 percent). The cost saving is an impressive $33,450 annually. One could afford to
install a variable speed drive even at considerable cost penalty. The savings in energy cost
are appreciable each year and continue throughout the life of the system.
51. 85
The pump efficiency is expected to drop
slightly due to the increases in the clearance
between the impeller tip and diffuser. Refer to
pump’s catalogue
Trimming Relations: PUMP Hand-Book
52. Trimming Relations:
Sulzer Co. Centrifugal Pump Hand-Book
m
D
D
H
H
Q
Q
'
'
'
86
n
n
H
H
D
Q
Q
D
D
=
=
'
.
'
.
'
m =2 for ΔD> 6%
m =3 for ΔD<1%
n =1/m
56. 90
New
Initial
Initial
The trimming”
pump impeller to D’
must be done in
steps. After each
step the modified
impeller should be
tested . Trimming
ends up when the
required head and
discharge are obtained
with a modified
impeller of Diam.>D’ .
“Trimming
”
90
59. Viscosity effects on Centrifugal pump &
Viscosity correction
93
• Pumps’ manufacturers test their pumps using
water at normal temperature,
•For viscous liquids such as oils, the friction
and other losses inside the pump lead to drop
in pump’s head, discharge and efficiency.
•Viscosity correction is necessary when pumping
viscous liquid using the nomogram presented By
American Hydraulic Institute .
60. VISCOSITY CORECTION FACTORS
(Courtesy of Hydraulic Institute, 1994 Edition)
94
. From Q at Bep - move
vertically up to the
corresponding Head
b) Then move horizontally
over to oil Viscosity
c) Then move vertically up
to read Coefficients Cn,
CQ and
CH @ : 0.6 QNW ,
0.8 QNW , 1.QNW
and 1.2 QNW
Head
Flow
Viscosity
94
Poise =0.1 Ns/m2.
Stoke =10-4 m2 /s
61. 95
This is applied for one
stage
in a Multi-Stage C.P.
From Q at Bep - move
vertically up to the
corresponding Head
b) Then move horizontally
over to oil Viscosity
c)Then move vertically up
to read Coefficients Cn,
CQ and CH @ : 0.6
,0.8,1,1.2QBep ,
Then Calclate: Qo=CQ.Qw
Ho=CH*Hw
Ƞo=Cƞ*Ƞw
67. Effect of
viscosity
100
20 60
40 80 120 140 160 180 200 220
Q GPM
H
FT
10
20
30
40
50
60
5
10
15
20
25
30
35
40
45
50
55
2
4
6
8
B. hp
Water
100 SSU=22 Sts 101
68. PRACTICAL MAXIMUM VISCOCITY FOR CENTRIFUGAL
PUMPS
102
Where to stop?
If we say that after a pump efficiency is reduce it to its half as
a limiting rule, then from the chart it follows that:
The practical maximum viscosity limit for
centrifugal pumps is approximately 500
centistokes
Note: POSITIVE DISPLACEMENT PUMPS CAN HANDLE
OILS OF MUCH HIGHER VISCOSITIES with Better
Operating Efficiency
75. CAVITATION
Low to high pressure transition
Low Pressure
High pressure
Cavitation occurs when vapour bubbles form
and then subsequently collapse as they move
along the flow path in an impeller.
76. 110
The minimum head inside suction pipe is
at the inlet of the pump & is given by :
In reality, the minimum pressure inside pump does not
exactly occurs at the inlet of the pump, but there is an
additional pressure drop inside the pump due to the change
in flow direction from axial to radial due to very high
rotational speed of the impeller (forced vortex). This action
leads to an increase in eddy losses and sudden increase in
flow velocity followed by reduction in pressure after the
inlet of the impeller as shown in figure .
Take Vs = Flow velocity at impeller eye.
g
V
h
H
H s
L
ss
ms
.
2
2
−
−
=
77. • Hms=Hss-Hl.s.-vs
2/2g
• Hmin. Inside pump= Hms-X,
• X= Dynamic head depression due to
forced vortex near the impeller
inlet.
• If Hmin.< Hvap, Cavitation Occurs.
• X=Function of (N,Q,Hm…) for a pump
• = Cavitation factor (Segma) * Hm
• Cavitation factor depends on pump
Ns,
• For no Cavitation ;
• Hms-σ *Hm > Hvap.-Hatm. 111
25
.
1
H
P
N
N o
s
=
78. 112
Figure 7.42 Some data on the cavitation head loss parameter, P= ∆H/NPSH, for
axial inducer pumps. The two symbols are for two different pumps.
79. 113
Cavitation begins ,when the pressure
inside the pump drops below the vapor
pressure of the liquid at the operating
temp. , liquid boils up quickly. This occurs
at low pressure region just after the
impeller inlet. Then rapidly compressed
when moved to impeller outlet (high
pressure side). Compression of the vapor
bubbles produces a small shock wave that
affects the impeller surface and pits
away the metal creating large eroded
areas and subsequent pump failure.
80. 114
Symptoms of cavitation
Cavitation in pumps can often be detected by a
1-characteristic generated Noise. It sounds like gravel
inside a concrete mixer due to bubbles generation
and Collapse.
2.High Vacuum reading on suction line.
3. Low discharge pressure & low flow
4. Excessive Power consumption .
Cavitation leads to excessive vibration, fatigue and
greatly increased impeller pitting and wear of pump
parts , bearing failures , sealing leakage , etc..
85. CAVITATION
Causes
1. Clogged suction pipe
2. Suction line too long
3. Suction line diameter too small
4. Suction lift too high
5. Valve on Suction Line only partially open
6. Discharge pressure too low
Results
1. Reduces pump flow rate and Head .
2. Drop in pump efficiency
3. Pump makes loud chattering noise
4. Future failures of seals on the shaft (Long term
5. Future failures due to metal erosion of impeller (Long term)
6. Shorten Pump Life Time.
86. 120
To prevent cavitation possible solutions are :
Hms- Segma*Hm> Hvap-Hatm.
Hms +Hatm- Hvap > Segma*Hm
or : NPSHA > NPSHR
The Net-Positive Suction Head Available (NPSHA ) is
the total suction head, at the impeller eye of the
pump minus the vapor pressure head of the pumped
liquid.
The term "Net" refers to the actual head at the pump
suction flange which should be “Positive” , since some
energy is lost in friction prior to the suction.
NPSHR is Net-Positive suction head required by pump
manufacturer as stated in pump catalogue.
88. 122
In order to avoid cavitation and guarantee proper
operation of the pump, it is desirable to have
NPSH available greater than the required NPSH
since this allows more flexibility in operation and
adds safety towards satisfactory performance.
margin
Safety
NPSH
NPSH Required
available +
As a guideline, the NPSH-Available should exceed
the NPSH-Required by a minimum of 1.5 m, or be
not less than 1.35 times the NPSH-Required,
89. CAVITATION Remedies
1- Correct selection & installation of pump
2-Increase the pressure at the pump inlet
3-Reduce the rotational speed if possible.
4-Reduce the NPSHR by using an inducer
impeller.
5-Minimize the head loss in suction pipe
due to friction and fittings to the possible
minimum
90. 124
6. Remove debris from suction line and
strainer at suction inlet.
7. Move pump closer to source tank/sump
8. Increase suction line diameter
9. Decrease suction lift requirement
10. Increase discharge pressure
11. Fully open Suction line valve
12. Select larger pump running slower which
will have lower Net Positive Suction Head
Required (NPSHR)
91. 125
The pressure at which the liquid
vaporizes is known as the vapor
pressure and it is specified for a
given temperature. If the
temperature changes, the vapor
pressure changes. Refer to the
accompanied table.
Temp C V.pressue
KN/m2
Density
Kg/m3
15 1.71 999
20 2.36 998
25 3.16 997
30 4.21 996
35 5.61 994
40 7.36 992
45 9.55 990
50 12.31 988
60 19.9 984
70 23.15 978
80 47.77 972
90
100
70.11 965
101.3 958
Table 1 Water Vapor Pressure
vs. temperature
{in absolute values }
93. 127
The pump manufacturers measure the
N.P.S.H. required in a test rig similar to
that shown in the corresponding Figure.
The system is run in a closed loop
where flow, total head and power
consumed are measured. In order to
provide a low N.P.S.H., a vacuum pump
is used to lower the pressure in the
suction tank that will provide a low
head at the pump suction. The pressure
in the suction tank is lowered until a
drop of 3% (see next figure ) of the total
head is measured. When that occurs
the N.P.S.H. is calculated and recorded
as the N.P.S.H. required for that
operating point. The experiment is
repeated for many operating points.
Heating coils are also used to increase
the water temperature thereby
increasing the vapor pressure and
further lowering the N.P.S.H. as needed.
How the pump manufacturers
measure N.P.S.H. required?
100. 134
INDUCER acts as an integrated booster pump, which
increases the suction pressure of the impeller inlet to
avoid evaporation and also cavitation. It provides a
reliable solution to eliminate cavitation problems. It
make an essential contribution to raise the operation
safety , life time and to reduce the life cycle costs
101. NPSH impeller = pressure
drop at impeller suction eye
INDUCER
HOW does it work?
Vapor pressure
Suction pressure
pressure
stream line
NPSH
impeller
Safety margin
pressure drops below
vapor pressure
→ Evaporation & Steam
bubbles
→ implodes at area of
higher pressure =
CAVITATION
absolute pressure 0
135
103. Conventional Inducer is designed to lower the NPSHR
value of the main pump in the range of the duty point, but
they only allow a limited operating range of the pump.
137
NPSHR with Inducer
NPSHR without Inducer
104. INDUCER enables a safe and reliable
operation with low NPSH values, the
handling of liquids close to the boiling point
and the handling of fluids containing
entrained gas. The wide operating range
allows operation at small capacities without
admitting more recirculation and vibrations,
and therefore improves the safety in
operation of the pump in process
applications. These characteristics have a
positive effect for the durability of bearing
and shaft seal, which leads to a decrease of
the life cycle costs (LCC). By means of the
Inducer it is possible to replace heavy,
expensive, slow running pumps by high
speed pumps with better efficiency, smaller
dimensions and lower total investment
costs, without losing operation safety.
138
105. Inducer in a Multi stage-Pump
Inducers can be positioned in front of the first
impeller on multistage pumps. The installation
then is similar as with single stage pumps.
139