This document discusses pumps and turbines as energy conversion devices. It begins by defining key terms like head, power, and efficiency as they relate to pumps and turbines. It then describes the main types of pumps and turbines, distinguishing between impulse and reaction turbines, and positive-displacement and dynamic pumps like centrifugal pumps. The document outlines how to determine the duty point by matching pump and system characteristics. It also discusses hydraulic scaling laws for relating pump performance at different speeds. Finally, it provides an overview of common pump and turbine designs and the problem of cavitation.
Experimental evaluation of a francis turbineeSAT Journals
Abstract Laboratory-Scale Francis Turbine has been used to generate experimental data for performance evaluation. The analysis presented here is based on turbine shaft load resulting in utilization of water power and includes overall efficiency, specific speed, unit quantities and critical cavitation factor. A modified critical cavitation factor relation has been obtained and verified with the existing relation. Keywords: Hydro Power, Francis Turbine, Turbine Performance, Cavitation Factor
This document discusses hydraulic turbines and pumps. It defines turbines as machines that convert hydraulic energy to mechanical energy, and pumps as the opposite, converting mechanical to hydraulic energy. It describes the key components and classifications of impulse and reaction turbines like the Pelton wheel and Francis turbine. It also covers turbine characteristics such as head, power, and efficiency. Characteristic curves are presented to show turbine and pump performance under varying operating conditions.
This document provides an overview of hydraulic turbines, including their history, classification, and key types. It discusses Pelton, Francis, Kaplan, and propeller turbines, comparing their components, working principles, efficiencies, applications, and variations. Hydraulic turbines convert the potential energy of water into rotational mechanical energy via impulse or reaction, and selection depends on factors like head, flow rate, and specific speed. Cavitation, runaway speed, and efficiencies such as hydraulic, mechanical, and overall are also defined.
Turbines convert hydraulic energy from flowing water into mechanical energy via a shaft. Francis turbines, invented in 1848, are a common type of inward reaction turbine that convert both kinetic and pressure energy. They have main components like a spiral casing, guide vanes, runner, and draft tube. Pelton wheels are impulse turbines that use nozzles to convert water's pressure energy into kinetic energy before it strikes buckets on the runner to rotate it. They are suitable for high head applications.
This document provides information on hydraulic turbines, including their definition, history, parts, types, and classifications. It focuses on the Pelton turbine, describing its working principle and key design aspects. The Pelton turbine uses the kinetic energy of water directed through a nozzle to spin buckets on a wheel. It is well-suited for high heads. Design considerations for the Pelton wheel include the velocity of its jet and buckets, the jet deflection angle, wheel and jet diameters, bucket dimensions, and the number of jets and buckets.
Watch Video of this presentation on Link: https://youtu.be/xIGlZ3UvLdw
For notes/articles, Visit my blog (link is given below).
For Video, Visit our YouTube Channel (link is given below).
Any Suggestions/doubts/reactions, please leave in the comment box.
Follow Us on
YouTube: https://www.youtube.com/channel/UCVPftVoKZoIxVH_gh09bMkw/
Blog: https://e-gyaankosh.blogspot.com/
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Hydraulic turbines convert hydraulic energy from water into electrical energy. There are three main types of hydraulic turbines: Pelton wheels, Francis turbines, and Kaplan turbines. Pelton wheels use the kinetic energy of water striking buckets to turn an impulse turbine, while Francis and Kaplan turbines are reaction turbines that convert both kinetic and pressure energy. Turbines consist of components like casings, runners, and guide vanes to efficiently direct water flow and extract energy.
Experimental evaluation of a francis turbineeSAT Journals
Abstract Laboratory-Scale Francis Turbine has been used to generate experimental data for performance evaluation. The analysis presented here is based on turbine shaft load resulting in utilization of water power and includes overall efficiency, specific speed, unit quantities and critical cavitation factor. A modified critical cavitation factor relation has been obtained and verified with the existing relation. Keywords: Hydro Power, Francis Turbine, Turbine Performance, Cavitation Factor
This document discusses hydraulic turbines and pumps. It defines turbines as machines that convert hydraulic energy to mechanical energy, and pumps as the opposite, converting mechanical to hydraulic energy. It describes the key components and classifications of impulse and reaction turbines like the Pelton wheel and Francis turbine. It also covers turbine characteristics such as head, power, and efficiency. Characteristic curves are presented to show turbine and pump performance under varying operating conditions.
This document provides an overview of hydraulic turbines, including their history, classification, and key types. It discusses Pelton, Francis, Kaplan, and propeller turbines, comparing their components, working principles, efficiencies, applications, and variations. Hydraulic turbines convert the potential energy of water into rotational mechanical energy via impulse or reaction, and selection depends on factors like head, flow rate, and specific speed. Cavitation, runaway speed, and efficiencies such as hydraulic, mechanical, and overall are also defined.
Turbines convert hydraulic energy from flowing water into mechanical energy via a shaft. Francis turbines, invented in 1848, are a common type of inward reaction turbine that convert both kinetic and pressure energy. They have main components like a spiral casing, guide vanes, runner, and draft tube. Pelton wheels are impulse turbines that use nozzles to convert water's pressure energy into kinetic energy before it strikes buckets on the runner to rotate it. They are suitable for high head applications.
This document provides information on hydraulic turbines, including their definition, history, parts, types, and classifications. It focuses on the Pelton turbine, describing its working principle and key design aspects. The Pelton turbine uses the kinetic energy of water directed through a nozzle to spin buckets on a wheel. It is well-suited for high heads. Design considerations for the Pelton wheel include the velocity of its jet and buckets, the jet deflection angle, wheel and jet diameters, bucket dimensions, and the number of jets and buckets.
Watch Video of this presentation on Link: https://youtu.be/xIGlZ3UvLdw
For notes/articles, Visit my blog (link is given below).
For Video, Visit our YouTube Channel (link is given below).
Any Suggestions/doubts/reactions, please leave in the comment box.
Follow Us on
YouTube: https://www.youtube.com/channel/UCVPftVoKZoIxVH_gh09bMkw/
Blog: https://e-gyaankosh.blogspot.com/
Facebook: https://www.facebook.com/egyaankosh/
Hydraulic turbines convert hydraulic energy from water into electrical energy. There are three main types of hydraulic turbines: Pelton wheels, Francis turbines, and Kaplan turbines. Pelton wheels use the kinetic energy of water striking buckets to turn an impulse turbine, while Francis and Kaplan turbines are reaction turbines that convert both kinetic and pressure energy. Turbines consist of components like casings, runners, and guide vanes to efficiently direct water flow and extract energy.
Pumps are used to move liquids through piping systems and raise their pressure by applying energy transformations. There are three main reasons for raising liquid pressure: overcoming static elevation changes, friction losses, and meeting process pressure requirements. Pumps are classified as either kinetic (centrifugal) or positive displacement depending on how energy is added to the liquid. Proper pump selection depends on factors like flow rate and viscosity. Cavitation can occur if the net positive suction head (NPSH) available falls below what is required by the pump.
Development of prototype turbine model for ultra-low head hydro power potenti...iosrjce
Clean source of energy is playing very vital role in today’s eco-friendly environment. Potential
energy available with water can be converted into useful work by maintaining the purpose of clean environment.
Hydro-power plant utilises the energy of water and can produce equivalent mechanical output. Hydro-electric
power plants are much more reliable and efficient as a renewable and clean source than the fossil fuel power
plants. The rivers in Western Maharashtra region flows from Sahyadri mountain towards Deccan platue with
steady gradient. In recent years, the environmental impacts are becoming difficult for developers to build new
dams because of opposition from environmentalists and people living on the land to be flooded. Therefore the
need has arisen to go for the small scale hydro power plants in the range of mini (few MW) and micro hydro
(kW) power plants. This paper discusses the conceptual design and development of a micro hydro power plant.
The developed model can be used at sites having head range of 0.5 to to 6 m. The required information was
collected from meteorological department and irrigation department of Kolhapur division of Government of
Maharashtra, India.
This presentation summarizes different types of hydro turbines classified based on how water acts on the turbine blades. Impulse turbines like Pelton and Turgo turbines use the kinetic energy of a high velocity water jet to turn the runner. Reaction turbines like Francis and Kaplan turbines use both the pressure and velocity of water. Francis turbines have fixed blades while Kaplan turbines have adjustable blades controlled by a servo mechanism. The presentation provides details on the working, typical specifications and applications of these common hydro turbine types to help select the optimal turbine for a hydroelectric project based on factors like head, flow, and output requirements.
Based on the given information:
ω = 6 rev/s = 360 rpm
Q = 10 ft3/s
hT = 20 ft
Wshaft = ρgQhT = 62.4hp
Calculating the specific speed:
N's =
ω(rpm)√Wshaft(bhp)
(hT(ft))5/4
=
360√62.4
205/4
= 580
From the specific speed chart, a turbine with a specific speed of 580
would be a Francis turbine, which is suited for mixed or radial flow.
Therefore, a Francis turbine should be selected for this
Hydraulic turbines convert the kinetic energy of flowing water into mechanical energy by passing water through blades attached to a rotating shaft. There are several types of hydraulic turbines classified based on flow path (axial, radial, mixed), pressure change (impulse, reaction), head (high, medium, low), and speed. Examples include Pelton wheels, Francis turbines, and Kaplan turbines. All hydraulic turbines work to convert the pressure and kinetic energy of flowing water into rotational energy to drive generators and produce electricity at hydroelectric power plants.
1. The document discusses various topics related to hydraulic turbines including their classification, selection, design principles of Pelton, Francis and Kaplan turbines, draft tubes, surge tanks, governing, unit quantities, characteristic curves, similitude analysis and cavitation.
2. Hydraulic turbines are classified based on the type of energy at the inlet, direction of flow through the runner, head at the inlet, and specific speed. Pelton wheels are impulse turbines suitable for high heads while Francis and Kaplan turbines are reaction turbines for lower heads.
3. The design of each turbine type involves guidelines related to jet ratio, speed ratio, velocities, discharge, power and efficiency calculations. Characteristic curves show the performance of a
Hydraulic Turbines-Classification,Impulse and Reaction Turbine, Layout of Hyd...Mechanicalstudents.com
Hydraulic turbines are machines which convert hydraulic energy into mechanical energy. If the machine transforms mechanical energy into hydraulic energy it is called a pump. Thus in turbines, fluid does work on the machine and machine produces power. but, the pump absorbs the power and work is done on the fluid.
For more information, visit https://mechanicalstudents.com/hydraulic-turbines-classification-impulse-and-reaction-turbine-layout-of-hydroelectric-power-plant/
The document describes an experiment conducted to study the performance of a Pelton wheel turbine. The experiment varied the water discharge through the turbine while keeping the head constant. Measurements were taken of the turbine's power output and efficiency at different discharges. The results were analyzed and discussed to determine how the turbine's properties changed with discharge and if they agreed with theoretical predictions. The key components of a Pelton wheel turbine are also outlined, including the stationary nozzle, rotating buckets, and how water is directed by the nozzle onto the buckets.
Turbines and recipocating pumps and miscellaneous hydraulic machinesMohit Yadav
This document provides information about various topics related to hydraulic machines covered in a fluid mechanics project. It includes 3 sections: turbines, centrifugal pumps, and reciprocating pumps. For turbines, it discusses the basic working principles and types of turbines such as Pelton, Kaplan, and Francis turbines. It provides details on the components and working of each turbine. For centrifugal pumps, it explains the working principle and components like impeller, casing, and discusses concepts such as priming. It also includes the velocity triangle and equations for work done.
This document discusses water turbines used in hydroelectric power plants. It defines key terms like specific energy, gross head, gross specific hydraulic energy, and gross power. It also describes different types of turbines like impulse turbines (Pelton, Turgo) and reaction turbines (Francis, Kaplan, Bulb) and compares their characteristics. It discusses concepts like specific speed, speed number, unit and specific quantities that are used to classify and select turbines based on factors like head, rotational speed, efficiency and more. It also provides examples of problems calculating speed number, specific speed and selecting the suitable turbine type.
Hydraulic turbines use the energy of flowing water to rotate a runner wheel and convert the energy into mechanical rotation. They are classified in several ways:
1. Based on the hydraulic action - Impulse turbines convert water's kinetic energy before striking the runner, while reaction turbines use both pressure and kinetic energy.
2. Based on flow direction - Radial flow turbines have inward or outward flow, axial flow is parallel to rotation, and tangential flow strikes the runner tangentially.
3. Based on head and flow - High, medium, low, and very low head turbines include Pelton, Francis, Kaplan, and propeller turbines respectively.
Performance of a_centrifugal_pump_autosavedDickens Mimisa
The document summarizes an experimental analysis of a centrifugal pump performed by a student. Key findings include:
- The experiment investigated the relationship between head, discharge, input power, and efficiency of a centrifugal pump under different revolution speeds.
- Data was collected manually and analyzed to determine the pump's characteristic curve and efficiency at varying flow rates.
- Results show efficiency increases with flow rate until peak efficiency is reached, then decreases as flow rate continues to rise.
The document discusses different types of turbines used to convert hydraulic energy from water into mechanical energy. It describes various ways turbines can be classified, including by the type of energy at the inlet, direction of water flow through the runner, head level at the inlet, and specific speed. Key turbine types discussed include Pelton, Francis, propeller, and Kaplan turbines. The Pelton turbine uses impulse and is suitable for high head applications. The Francis turbine uses inward radial flow and is used for medium head. The Kaplan turbine has adjustable vanes and is used for low head applications.
This document discusses different types of turbines, focusing on Francis turbines. It describes how Francis turbines work by using both kinetic and pressure energy of flowing water. Sir James Francis invented the Francis turbine in Lowell, Massachusetts in the 1840s by redesigning an earlier Boyden turbine to significantly increase efficiency from 65% to 88%. Francis turbines are now the most commonly used water turbine for power generation, with efficiencies between 80-94%. They can operate in heads from 10-650 meters and generate 10-750 megawatts typically. The key components of a Francis turbine installation and its working mechanism are explained.
This document classifies and describes various types of water turbines. It divides turbines into two main categories: reaction turbines and impulse turbines. Reaction turbines include Francis, Kaplan, Tyson, and Gorlov turbines, which use the reaction force of water to turn the runner. Impulse turbines include Pelton wheels, Turgo turbines, water wheels, cross flow turbines, and Jonval turbines, which use the impulse from water jets to turn the runner. Examples and brief descriptions are provided for each type of turbine.
This document describes the design and functioning of a hydraulically operated backhoe powered by an internal combustion engine. It discusses the key components of a backhoe including the bucket, boom, dipper stick, chassis, engine, hydraulic mechanism, and wheels. It then explains the principles of hydraulics, specifically Pascal's law and hydrostatic transmission. It provides details on the operation of hydraulic cylinders and components like the cylinder barrel, base, head, piston, and rod gland. Finally, it briefly discusses the mini backhoe mechanism and hydraulic pump and hose types.
ME 6021 - HYDRAULICS AND PNEUMATICS / UNIT II - HYDRAULIC SYSTEM AND COMPONENTSSANTHOSH00775
This document provides an overview of hydraulic systems and components. It discusses various types of hydraulic pumps including centrifugal, gear, vane, piston and axial flow pumps. It also describes hydraulic actuators like cylinders and motors. Finally, it covers control components such as directional control valves, pressure control valves and flow control valves.
Jet propulsion means the propulsion or movement of the bodies such as ships, aircrafts, rocket etc. with the help of jet.
It is well known from Newton’s Law that to change momentum of fluid, a force is required. Similarly, when momentum of fluid is changed, a force is generated. This principle is made use in hydraulic turbine.
Turbines work by converting the kinetic energy of a moving fluid like water, steam, gas or wind into mechanical rotational energy. There are different types of turbines that are designed based on how the fluid interacts with the turbine blades including impulse turbines where the fluid hits the blades at high speed, and reaction turbines where the pressure of the fluid changes as it passes through the rotor blades. Common types of turbines include water turbines like the Pelton, Francis and Kaplan turbines, steam turbines used in power plants, gas turbines that power aircraft and generators, and wind turbines that convert wind energy into electricity.
solution of introductoin to fluid mechanics and machines(Prof. Som and Prof. ...pankaj dumka
The document outlines the key details of a loan agreement between two parties, John Doe and Sample Bank. It specifies that John Doe is borrowing $100,000 from Sample Bank at an annual interest rate of 5% to be repaid over 10 years in monthly installments. The document details the payment schedule, late fees, and what would constitute default of the loan agreement.
The document describes specifications for several series of axial piston pumps for open loop hydraulic systems, including medium heavy duty series PPV100 and PPV100S, medium heavy duty series PPV101, heavy duty series PPV102, and light duty series PPV103. Tables are provided listing the model, geometric displacement, rated operating pressure, maximum drive speed, and peak pressure for pump models within each series.
Pumps are used to move liquids through piping systems and raise their pressure by applying energy transformations. There are three main reasons for raising liquid pressure: overcoming static elevation changes, friction losses, and meeting process pressure requirements. Pumps are classified as either kinetic (centrifugal) or positive displacement depending on how energy is added to the liquid. Proper pump selection depends on factors like flow rate and viscosity. Cavitation can occur if the net positive suction head (NPSH) available falls below what is required by the pump.
Development of prototype turbine model for ultra-low head hydro power potenti...iosrjce
Clean source of energy is playing very vital role in today’s eco-friendly environment. Potential
energy available with water can be converted into useful work by maintaining the purpose of clean environment.
Hydro-power plant utilises the energy of water and can produce equivalent mechanical output. Hydro-electric
power plants are much more reliable and efficient as a renewable and clean source than the fossil fuel power
plants. The rivers in Western Maharashtra region flows from Sahyadri mountain towards Deccan platue with
steady gradient. In recent years, the environmental impacts are becoming difficult for developers to build new
dams because of opposition from environmentalists and people living on the land to be flooded. Therefore the
need has arisen to go for the small scale hydro power plants in the range of mini (few MW) and micro hydro
(kW) power plants. This paper discusses the conceptual design and development of a micro hydro power plant.
The developed model can be used at sites having head range of 0.5 to to 6 m. The required information was
collected from meteorological department and irrigation department of Kolhapur division of Government of
Maharashtra, India.
This presentation summarizes different types of hydro turbines classified based on how water acts on the turbine blades. Impulse turbines like Pelton and Turgo turbines use the kinetic energy of a high velocity water jet to turn the runner. Reaction turbines like Francis and Kaplan turbines use both the pressure and velocity of water. Francis turbines have fixed blades while Kaplan turbines have adjustable blades controlled by a servo mechanism. The presentation provides details on the working, typical specifications and applications of these common hydro turbine types to help select the optimal turbine for a hydroelectric project based on factors like head, flow, and output requirements.
Based on the given information:
ω = 6 rev/s = 360 rpm
Q = 10 ft3/s
hT = 20 ft
Wshaft = ρgQhT = 62.4hp
Calculating the specific speed:
N's =
ω(rpm)√Wshaft(bhp)
(hT(ft))5/4
=
360√62.4
205/4
= 580
From the specific speed chart, a turbine with a specific speed of 580
would be a Francis turbine, which is suited for mixed or radial flow.
Therefore, a Francis turbine should be selected for this
Hydraulic turbines convert the kinetic energy of flowing water into mechanical energy by passing water through blades attached to a rotating shaft. There are several types of hydraulic turbines classified based on flow path (axial, radial, mixed), pressure change (impulse, reaction), head (high, medium, low), and speed. Examples include Pelton wheels, Francis turbines, and Kaplan turbines. All hydraulic turbines work to convert the pressure and kinetic energy of flowing water into rotational energy to drive generators and produce electricity at hydroelectric power plants.
1. The document discusses various topics related to hydraulic turbines including their classification, selection, design principles of Pelton, Francis and Kaplan turbines, draft tubes, surge tanks, governing, unit quantities, characteristic curves, similitude analysis and cavitation.
2. Hydraulic turbines are classified based on the type of energy at the inlet, direction of flow through the runner, head at the inlet, and specific speed. Pelton wheels are impulse turbines suitable for high heads while Francis and Kaplan turbines are reaction turbines for lower heads.
3. The design of each turbine type involves guidelines related to jet ratio, speed ratio, velocities, discharge, power and efficiency calculations. Characteristic curves show the performance of a
Hydraulic Turbines-Classification,Impulse and Reaction Turbine, Layout of Hyd...Mechanicalstudents.com
Hydraulic turbines are machines which convert hydraulic energy into mechanical energy. If the machine transforms mechanical energy into hydraulic energy it is called a pump. Thus in turbines, fluid does work on the machine and machine produces power. but, the pump absorbs the power and work is done on the fluid.
For more information, visit https://mechanicalstudents.com/hydraulic-turbines-classification-impulse-and-reaction-turbine-layout-of-hydroelectric-power-plant/
The document describes an experiment conducted to study the performance of a Pelton wheel turbine. The experiment varied the water discharge through the turbine while keeping the head constant. Measurements were taken of the turbine's power output and efficiency at different discharges. The results were analyzed and discussed to determine how the turbine's properties changed with discharge and if they agreed with theoretical predictions. The key components of a Pelton wheel turbine are also outlined, including the stationary nozzle, rotating buckets, and how water is directed by the nozzle onto the buckets.
Turbines and recipocating pumps and miscellaneous hydraulic machinesMohit Yadav
This document provides information about various topics related to hydraulic machines covered in a fluid mechanics project. It includes 3 sections: turbines, centrifugal pumps, and reciprocating pumps. For turbines, it discusses the basic working principles and types of turbines such as Pelton, Kaplan, and Francis turbines. It provides details on the components and working of each turbine. For centrifugal pumps, it explains the working principle and components like impeller, casing, and discusses concepts such as priming. It also includes the velocity triangle and equations for work done.
This document discusses water turbines used in hydroelectric power plants. It defines key terms like specific energy, gross head, gross specific hydraulic energy, and gross power. It also describes different types of turbines like impulse turbines (Pelton, Turgo) and reaction turbines (Francis, Kaplan, Bulb) and compares their characteristics. It discusses concepts like specific speed, speed number, unit and specific quantities that are used to classify and select turbines based on factors like head, rotational speed, efficiency and more. It also provides examples of problems calculating speed number, specific speed and selecting the suitable turbine type.
Hydraulic turbines use the energy of flowing water to rotate a runner wheel and convert the energy into mechanical rotation. They are classified in several ways:
1. Based on the hydraulic action - Impulse turbines convert water's kinetic energy before striking the runner, while reaction turbines use both pressure and kinetic energy.
2. Based on flow direction - Radial flow turbines have inward or outward flow, axial flow is parallel to rotation, and tangential flow strikes the runner tangentially.
3. Based on head and flow - High, medium, low, and very low head turbines include Pelton, Francis, Kaplan, and propeller turbines respectively.
Performance of a_centrifugal_pump_autosavedDickens Mimisa
The document summarizes an experimental analysis of a centrifugal pump performed by a student. Key findings include:
- The experiment investigated the relationship between head, discharge, input power, and efficiency of a centrifugal pump under different revolution speeds.
- Data was collected manually and analyzed to determine the pump's characteristic curve and efficiency at varying flow rates.
- Results show efficiency increases with flow rate until peak efficiency is reached, then decreases as flow rate continues to rise.
The document discusses different types of turbines used to convert hydraulic energy from water into mechanical energy. It describes various ways turbines can be classified, including by the type of energy at the inlet, direction of water flow through the runner, head level at the inlet, and specific speed. Key turbine types discussed include Pelton, Francis, propeller, and Kaplan turbines. The Pelton turbine uses impulse and is suitable for high head applications. The Francis turbine uses inward radial flow and is used for medium head. The Kaplan turbine has adjustable vanes and is used for low head applications.
This document discusses different types of turbines, focusing on Francis turbines. It describes how Francis turbines work by using both kinetic and pressure energy of flowing water. Sir James Francis invented the Francis turbine in Lowell, Massachusetts in the 1840s by redesigning an earlier Boyden turbine to significantly increase efficiency from 65% to 88%. Francis turbines are now the most commonly used water turbine for power generation, with efficiencies between 80-94%. They can operate in heads from 10-650 meters and generate 10-750 megawatts typically. The key components of a Francis turbine installation and its working mechanism are explained.
This document classifies and describes various types of water turbines. It divides turbines into two main categories: reaction turbines and impulse turbines. Reaction turbines include Francis, Kaplan, Tyson, and Gorlov turbines, which use the reaction force of water to turn the runner. Impulse turbines include Pelton wheels, Turgo turbines, water wheels, cross flow turbines, and Jonval turbines, which use the impulse from water jets to turn the runner. Examples and brief descriptions are provided for each type of turbine.
This document describes the design and functioning of a hydraulically operated backhoe powered by an internal combustion engine. It discusses the key components of a backhoe including the bucket, boom, dipper stick, chassis, engine, hydraulic mechanism, and wheels. It then explains the principles of hydraulics, specifically Pascal's law and hydrostatic transmission. It provides details on the operation of hydraulic cylinders and components like the cylinder barrel, base, head, piston, and rod gland. Finally, it briefly discusses the mini backhoe mechanism and hydraulic pump and hose types.
ME 6021 - HYDRAULICS AND PNEUMATICS / UNIT II - HYDRAULIC SYSTEM AND COMPONENTSSANTHOSH00775
This document provides an overview of hydraulic systems and components. It discusses various types of hydraulic pumps including centrifugal, gear, vane, piston and axial flow pumps. It also describes hydraulic actuators like cylinders and motors. Finally, it covers control components such as directional control valves, pressure control valves and flow control valves.
Jet propulsion means the propulsion or movement of the bodies such as ships, aircrafts, rocket etc. with the help of jet.
It is well known from Newton’s Law that to change momentum of fluid, a force is required. Similarly, when momentum of fluid is changed, a force is generated. This principle is made use in hydraulic turbine.
Turbines work by converting the kinetic energy of a moving fluid like water, steam, gas or wind into mechanical rotational energy. There are different types of turbines that are designed based on how the fluid interacts with the turbine blades including impulse turbines where the fluid hits the blades at high speed, and reaction turbines where the pressure of the fluid changes as it passes through the rotor blades. Common types of turbines include water turbines like the Pelton, Francis and Kaplan turbines, steam turbines used in power plants, gas turbines that power aircraft and generators, and wind turbines that convert wind energy into electricity.
solution of introductoin to fluid mechanics and machines(Prof. Som and Prof. ...pankaj dumka
The document outlines the key details of a loan agreement between two parties, John Doe and Sample Bank. It specifies that John Doe is borrowing $100,000 from Sample Bank at an annual interest rate of 5% to be repaid over 10 years in monthly installments. The document details the payment schedule, late fees, and what would constitute default of the loan agreement.
The document describes specifications for several series of axial piston pumps for open loop hydraulic systems, including medium heavy duty series PPV100 and PPV100S, medium heavy duty series PPV101, heavy duty series PPV102, and light duty series PPV103. Tables are provided listing the model, geometric displacement, rated operating pressure, maximum drive speed, and peak pressure for pump models within each series.
This document provides an overview of fluid mechanics concepts across 14 lessons. It begins with an introduction that defines a fluid, discusses fluid properties and the governing equations. Subsequent lessons cover topics like fluid statics, kinematics, dynamics, the energy equation, and its applications. Later lessons address viscous flow, pipe flows, open channels, and pumps/turbines. The introduction provides historical context, defines density, pressure, compressibility, viscosity, and cavitation. It also introduces the concept of modeling fluids as a continuum using differential volumes and governing equations.
The document discusses the benefits of exercise for mental health. Regular physical activity can help reduce anxiety and depression and improve mood and cognitive functioning. Exercise causes chemical changes in the brain that may help boost feelings of calmness and well-being.
The document discusses various properties of aggregates that are important for construction materials. It describes how the modulus of elasticity and strength of aggregates can affect the properties of concrete. It also discusses how the gradation, or particle size distribution, of an aggregate impacts qualities like stiffness, stability, durability and strength. Sieve analysis is used to determine the gradation of an aggregate sample by passing it through a series of sieves and measuring the material retained on each sieve.
1. The document presents information on centrifugal and reciprocating pumps, including their basic workings, components, uses, and efficiencies.
2. Centrifugal pumps use centrifugal force to accelerate and move fluid outwards from the center to increase pressure, while reciprocating pumps use pistons or plungers that move back and forth to displace fluid.
3. Key components of centrifugal pumps include casings, impellers, while reciprocating pumps have cylinders, pistons, valves. Both are used widely for irrigation, industry, buildings and other purposes.
Positive displacement pumps work by trapping a fixed amount of fluid and forcing it to discharge. There are three main types: reciprocating pumps use pistons, diaphragm pumps use flexible diaphragms, and linear pumps use linear motion. Reciprocating pumps are commonly used for high pressure applications like well services. Diaphragm pumps are suitable for handling corrosive or abrasive liquids since only the diaphragm and valves contact the fluid. Positive displacement pumps can handle high viscosity liquids efficiently and are used widely in industries like oil and gas, mining, and more.
The document is the solutions manual for a fluid mechanics textbook. It contains solutions to example problems from Chapter 1 which covers basic concepts in fluid mechanics, including definitions of different types of flows, fluid properties, forces, and units. The solutions provide concise explanations and calculations for each question with the relevant equations, assumptions, analysis, and discussions of the results.
1) Positive displacement pumps work by trapping a fixed amount of fluid and forcing that volume into the discharge pipe, causing the fluid to move in a constant flow.
2) Reciprocating pumps use a piston or plunger that executes a reciprocating motion inside a closed cylinder to push the fluid, with common examples including piston pumps and diaphragm pumps.
3) Diaphragm pumps use a flexible diaphragm and check valves to pump fluids, and can handle corrosive or abrasive liquids since the only parts in contact with the fluid are the valves.
This document provides a project report on the design, installation, and fabrication of a reciprocating pump. It includes sections on the project plan, classification of reciprocating pumps, pump components, performance, selection, design calculations, and applications. The objectives are to demonstrate a functional reciprocating pump and facilitate local access to water. The report covers pump types, components, performance characterization, and applications in areas like water supply.
(1) The document discusses water supply distribution networks and their components. It describes various natural and non-traditional water sources, as well as water quality parameters and treatment methods.
(2) Distribution networks use reservoirs, transmission pipelines, and distribution mains to deliver water from treatment plants to consumers. The document discusses different network layouts and design considerations like minimizing dead ends.
(3) Pipe network analysis methods like Hardy-Cross and nodal methods are presented to calculate pipe flows and node pressures. An example applies Hardy-Cross iteration to determine flows in a pipe loop that balances the head loss around the loop.
Hydraulic machines use liquid flow to transfer mechanical energy between the liquid and a rotating component. There are two main types: hydraulic turbines, where the rotating component receives energy from the liquid flow; and pumps, where energy is transferred from the rotating component to the liquid. Common hydraulic turbines include impulse turbines like the Pelton wheel, which use jet momentum changes, and reaction turbines like the Francis turbine, where pressure and kinetic energy changes drive the rotating runner. Turbines are classified based on factors such as the type of energy used, direction of liquid flow, operating head, and specific speed. Hydraulic power plants typically include a dam, penstock, water turbine, and tailrace to harness potential and kinetic energy of water
The pdf contains explanation about the centrifugal pumps. It is usually studied by Mechanical or Civil engineering students. This pdf file will help for the students from these fields.
The document discusses the selection and application of pumps. It begins by defining different types of pumps, including piston pumps, plunger pumps, diaphragm pumps, and centrifugal pumps. It then discusses key considerations for pump selection like fluid characteristics, pressure requirements, and space availability. The document also covers pump performance concepts like net positive suction head (NPSH), total dynamic head, brake horsepower calculations, and affinity laws relating pump parameters like flow, head, and rpm. Overall, the document provides an overview of different pump types and the important technical factors to examine when choosing a pump for a given application.
Southern Methodist UniversityBobby B. Lyle School of Engineeri.docxwhitneyleman54422
This document discusses pump selection and piping systems for fluid flow. It provides definitions for different types of pumps (e.g. centrifugal, positive displacement) and describes how they are used for various applications. It also discusses concepts like pump curves, system curves and selecting a suitable pump for a given piping system. Finally, it covers topics like multiple pipe systems with pipes in series, parallel and branching configurations, and how to analyze flow through such complex pipe networks.
1. Turbomachines such as centrifugal pumps transfer energy from a rotor to a fluid. Centrifugal pumps are classified based on the extent and type of fluid flow, and whether they absorb or produce energy.
2. Centrifugal pumps use a rotating impeller to impart velocity to the fluid and increase its pressure. They are commonly used to transport liquids through conversion of rotational kinetic energy.
3. Positive displacement pumps move fluid by trapping a fixed volume and forcing that volume into the discharge pipe. They are classified based on construction and include gear pumps, vane pumps, piston pumps, and more. Flow is constant with changing pressure in positive displacement pumps.
This document discusses various topics related to hydraulic turbines, including:
1. Classification, selection, and design of impulse turbines like the Pelton wheel and reaction turbines like the Francis and Kaplan turbines.
2. Components like the draft tube, surge tanks, and governing systems.
3. Concepts like unit speed, unit discharge, unit power, and characteristic curves used to analyze turbine performance.
4. Cavitation in hydraulic turbines.
Hydraulic turbines convert hydraulic energy from flowing water into mechanical energy. They are classified as either reaction turbines or impulse turbines. Reaction turbines experience pressure changes through both fixed and moving blades, while impulse turbines only experience velocity changes from jet impacts. Common reaction turbines are Francis and Kaplan turbines, which are used in low- and medium-head applications like dams. The Pelton wheel is an example of an impulse turbine, where individual jets strike rotating buckets to generate torque. Power developed depends on factors like efficiency, density, head, flow rate.
A water turbine is a rotary engine that captures energy from moving water. It was developed in the 19th century for industrial power production. There are two main types - reaction turbines, which rely on changes in water pressure, and impulse turbines, which rely on changes in water velocity. Francis turbines are the most widely used reaction turbine, while Pelton wheels are common impulse turbines. Water turbines come in various designs depending on factors like available water head and flow rate. They are designed to efficiently harness hydraulic energy with high mechanical efficiencies over 90% for power generation.
The document discusses different types of hydraulic turbines used to convert hydraulic energy into mechanical energy. It defines hydraulic turbines and provides examples such as the Pelton wheel, Francis, and Kaplan turbines. It then classifies hydraulic turbines based on factors like the energy at the inlet, direction of flow through the runner, head available at the inlet, and specific speed. The key components and working of Pelton wheel, Francis, and Kaplan turbines are explained along with diagrams. Concepts like velocity triangles, work done, efficiencies, and design aspects are covered for Pelton wheel turbines. Draft tubes, their functions and types are also summarized.
The document discusses different types of hydraulic turbines used to convert hydraulic energy from flowing water into mechanical energy. It describes Pelton, Francis, and Kaplan turbines, their main components, working principles, and classifications. Pelton turbines use impulse and are suitable for high heads. Francis turbines are reaction turbines that can achieve over 95% efficiency and are most commonly used. Kaplan turbines have adjustable blades and are used for low heads. The document also covers hydraulic turbine efficiencies, velocity triangles, draft tubes, and factors considered in turbine selection and design.
An Experimental Prototype for Low Head Small Hydro Power Generation Using Hydram - University of Nairobi
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Different power generatrion diagram and its breif explain by swapnil dSwapnil Dhage
The document describes different types of power plants:
1) Hydroelectric plants use falling water to rotate turbines and generate electricity. Key components include dams, penstocks, turbines, generators, and transformers.
2) Thermal plants burn fuels to create high-pressure steam that drives turbines connected to generators. They include boilers, steam turbines, condensers, and feedwater pumps.
3) Wind turbines use rotor blades to convert wind's kinetic energy into mechanical energy that spins generators. Their components are rotors, drive trains, nacelles, towers, and machine controls.
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This document summarizes different types of hydroelectric power plants and turbines. It describes impulse and reaction turbines, including Pelton, Francis, and Kaplan turbines. It provides diagrams of hydroelectric and pump storage plants. Key concepts covered include gross and net heads, discharge, water power, brake power, efficiency, and speed. Fundamental equations for hydroelectric systems are given. Common terms are defined. Sample problems demonstrate calculations for hydroelectric plant design and performance analysis.
Hydraulic turbines convert the potential energy of water into electrical energy. They are classified based on factors like head, flow rate, direction of water flow, and specific speed. Common turbine types include impulse (Pelton) and reaction (Francis, Kaplan) turbines. Proper turbine selection depends on site conditions like head and flow. Draft tubes recover exit energy in mixed and axial flow turbines. Cavitation can damage turbine blades and is avoided through design techniques. Pump-turbines (PATs) provide a low-cost option for micro-hydro sites, but have performance limitations compared to dedicated turbines.
Description about working with sketches of: Reciprocating pump, Centrifugal...Anish mon T.S
Hydraulic turbines and pumps are used to convert the kinetic energy of flowing water into mechanical energy of rotation. There are two main types of hydraulic turbines - impulse turbines and reaction turbines. Impulse turbines only convert water's kinetic energy while reaction turbines convert both kinetic and pressure energy. Common impulse turbines include Pelton wheels, while common reaction turbines include Francis, Kaplan, and propeller turbines. Hydraulic pumps are used to move fluids and increase their pressure. The two main types are positive displacement pumps like reciprocating pumps, and rotodynamic or centrifugal pumps. Reciprocating pumps use pistons or plungers while centrifugal pumps use an impeller to impart centrifugal force on water.
The document provides an overview of rotating equipment, including:
1. Rotating equipment is driven by prime movers such as turbines, engines, and electric motors. Examples of rotating equipment include pumps, compressors, mixers, and generators.
2. Specific types of prime movers are discussed in more detail, including steam and gas turbines, water turbines, wind turbines, internal combustion engines, and electric motors.
3. Common types of rotating equipment that are driven include centrifugal and positive displacement pumps, compressors, agitators, mixers, and reactors. Specific examples like centrifugal pumps, screw pumps, and centrifugal compressors are also described.
The document provides an overview of rotating equipment, including:
- Prime movers that drive rotating equipment such as turbines, engines, and electric motors.
- Rotating equipment that is driven like pumps, compressors, mixers, and generators.
- Connectors that transmit power between drivers and driven equipment, including modifiers like gearboxes and couplings.
- Specific rotating equipment is discussed in more detail like centrifugal pumps, compressors, and agitators. Pump and equipment data sheets are also overviewed.
A turbine is a rotary mechanical device that extracts energy from a fluid flow and converts it into useful work. The work produced by a turbine can be used for generating electrical power when combined with a generator.
Turbines are the hydraulic machines which convert hydraulic energy into mechanical energy.
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https://www.theurbancrews.com/celeb/matt-rife-cancels-bloomington-show/
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The teleprotection market size has grown
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The Unbelievable Tale of Dwayne Johnson Kidnapping: A Riveting Sagagreendigital
Introduction
The notion of Dwayne Johnson kidnapping seems straight out of a Hollywood thriller. Dwayne "The Rock" Johnson, known for his larger-than-life persona, immense popularity. and action-packed filmography, is the last person anyone would envision being a victim of kidnapping. Yet, the bizarre and riveting tale of such an incident, filled with twists and turns. has captured the imagination of many. In this article, we delve into the intricate details of this astonishing event. exploring every aspect, from the dramatic rescue operation to the aftermath and the lessons learned.
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The Origins of the Dwayne Johnson Kidnapping Saga
Dwayne Johnson: A Brief Background
Before discussing the specifics of the kidnapping. it is crucial to understand who Dwayne Johnson is and why his kidnapping would be so significant. Born May 2, 1972, Dwayne Douglas Johnson is an American actor, producer, businessman. and former professional wrestler. Known by his ring name, "The Rock," he gained fame in the World Wrestling Federation (WWF, now WWE) before transitioning to a successful career in Hollywood.
Johnson's filmography includes blockbuster hits such as "The Fast and the Furious" series, "Jumanji," "Moana," and "San Andreas." His charismatic personality, impressive physique. and action-star status have made him a beloved figure worldwide. Thus, the news of his kidnapping would send shockwaves across the globe.
Setting the Scene: The Day of the Kidnapping
The incident of Dwayne Johnson's kidnapping began on an ordinary day. Johnson was filming his latest high-octane action film set to break box office records. The location was a remote yet scenic area. chosen for its rugged terrain and breathtaking vistas. perfect for the film's climactic scenes.
But, beneath the veneer of normalcy, a sinister plot was unfolding. Unbeknownst to Johnson and his team, a group of criminals had planned his abduction. hoping to leverage his celebrity status for a hefty ransom. The stage was set for an event that would soon dominate worldwide headlines and social media feeds.
The Abduction: Unfolding the Dwayne Johnson Kidnapping
The Moment of Capture
On the day of the kidnapping, everything seemed to be proceeding as usual on set. Johnson and his co-stars and crew were engrossed in shooting a particularly demanding scene. As the day wore on, the production team took a short break. providing the kidnappers with the perfect opportunity to strike.
The abduction was executed with military precision. A group of masked men, armed and organized, infiltrated the set. They created chaos, taking advantage of the confusion to isolate Johnson. Johnson was outnumbered and caught off guard despite his formidable strength and fighting skills. The kidnappers overpowered him, bundled him into a waiting vehicle. and sped away, leaving everyone on set in a state of shock and disbelief.
The Immediate Aftermath
The immediate aftermath of the Dwayne Johnson kidnappin
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Orpah Winfrey Dwayne Johnson: Titans of Influence and Inspirationgreendigital
Introduction
In the realm of entertainment, few names resonate as Orpah Winfrey Dwayne Johnson. Both figures have carved unique paths in the industry. achieving unparalleled success and becoming iconic symbols of perseverance, resilience, and inspiration. This article delves into the lives, careers. and enduring legacies of Orpah Winfrey Dwayne Johnson. exploring how their journeys intersect and what we can learn from their remarkable stories.
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Early Life and Backgrounds
Orpah Winfrey: From Humble Beginnings to Media Mogul
Orpah Winfrey, often known as Oprah due to a misspelling on her birth certificate. was born on January 29, 1954, in Kosciusko, Mississippi. Raised in poverty by her grandmother, Winfrey's early life was marked by hardship and adversity. Despite these challenges. she demonstrated a keen intellect and an early talent for public speaking.
Winfrey's journey to success began with a scholarship to Tennessee State University. where she studied communication. Her first job in media was as a co-anchor for the local evening news in Nashville. This role paved the way for her eventual transition to talk show hosting. where she found her true calling.
Dwayne Johnson: From Wrestling Royalty to Hollywood Superstar
Dwayne Johnson, also known by his ring name "The Rock," was born on May 2, 1972, in Hayward, California. He comes from a family of professional wrestlers, with both his father, Rocky Johnson. and his grandfather, Peter Maivia, being notable figures in the wrestling world. Johnson's early life was spent moving between New Zealand and the United States. experiencing a variety of cultural influences.
Before entering the world of professional wrestling. Johnson had aspirations of becoming a professional football player. He played college football at the University of Miami. where he was part of a national championship team. But, injuries curtailed his football career, leading him to follow in his family's footsteps and enter the wrestling ring.
Career Milestones
Orpah Winfrey: The Queen of All Media
Winfrey's career breakthrough came in 1986 when she launched "The Oprah Winfrey Show." The show became a cultural phenomenon. drawing millions of viewers daily and earning many awards. Winfrey's empathetic and candid interviewing style resonated with audiences. helping her tackle diverse and often challenging topics.
Beyond her talk show, Winfrey expanded her empire to include the creation of Harpo Productions. a multimedia production company. She also launched "O, The Oprah Magazine" and OWN: Oprah Winfrey Network, further solidifying her status as a media mogul.
Dwayne Johnson: From The Ring to The Big Screen
Dwayne Johnson's wrestling career took off in the late 1990s. when he became one of the most charismatic and popular figures in WWE. His larger-than-life persona and catchphrases endeared him to fans. making him a household name. But, Johnson had ambitions beyond the wrestling ring.
In the early 20
Orpah Winfrey Dwayne Johnson: Titans of Influence and Inspiration
22dsad
1. Hydraulics 2 T4-1 David Apsley
TOPIC T4: PUMPS AND TURBINES AUTUMN 2013
Objectives
(1) Understand the role of pumps and turbines as energy-conversion devices and use,
appropriately, the terms head, power and efficiency.
(2) Be aware of the main types of pumps and turbines and the distinction between impulse
and reaction turbines and between radial, axial and mixed-flow devices.
(3) Match pump characteristics and system characteristics to determine the duty point.
(4) Calculate characteristics for pumps in series and parallel and use the hydraulic scaling
laws to calculate pump characteristics at different speeds.
(5) Select the type of pump or turbine on the basis of specific speed.
(6) Understand the mechanics of a centrifugal pump and an impulse turbine.
(7) Recognise the problem of cavitation and how it can be avoided.
1. Energy conversion
1.1 Energy transfer in pumps and turbines
1.2 Power
1.3 Efficiency
2. Types of pumps and turbines
2.1 Impulse and reaction turbines
2.2 Positive-displacement and dynamic pumps
2.3 Radial, axial and mixed-flow devices
2.4 Common types of turbine
3. Pump and system characteristics
3.1 Pump characteristics
3.2 System characteristics
3.3 Finding the duty point
3.4 Pumps in parallel and in series
4. Hydraulic scaling
4.1 Dimensional analysis
4.2 Change of speed
4.3 Specific speed
5. Mechanics of rotodynamic devices
5.1 Centrifugal pump
5.2 Pelton wheel
6. Cavitation
References
White (2006) – Chapter 11
Hamill (2001) – Chapter 11
Chadwick and Morfett (2004) – Chapter 7
Massey (2005) – Chapter 12
2. Hydraulics 2 T4-2 David Apsley
1. Energy Conversion
1.1 Energy Transfer in Pumps and Turbines
Pumps and turbines are energy conversion devices:
pumps turn electrical or mechanical energy into fluid energy;
turbines turn fluid energy into electrical or mechanical energy.
The energy per unit weight is the head, H:
g
V
z
g
p
H
2ρ
2
The first two terms on the RHS comprise the piezometric head. The last term is the dynamic
head.
1.2 Power
Power = rate of conversion of energy.
If a mass m is raised through a height H it gains energy mgH. If it does so in time t then the
rate of conversion is mgH/t.
For a fluid in motion the mass flow rate (m/t) is ρQ. The rate of conversion to or from fluid
energy when the total head is changed by H is, therefore, ρQgH, or
gQHpower ρ
1.3 Efficiency
Efficiency, η, is given by
in
out
power
power
η
where “powerout” refers to the useful power; i.e. excluding losses.
For turbines:
gQH
powerout
ρ
η
For pumps:
inpower
gQHρ
η
Example.
A pump lifts water from a large tank at a rate of 30 L s–1
. If the input power is 10 kW and the
pump is operating at an efficiency of 40%, find:
(a) the head developed across the pump;
(b) the maximum height to which it can raise water if the delivery pipe is vertical, with
diameter 100 mm and friction factor λ = 0.015.
Answer: (a) 13.6 m; (b) 12.2 m
3. Hydraulics 2 T4-3 David Apsley
2. Types of Pumps and Turbines
2.1 Impulse and reaction turbines
In a pump or turbine a change in fluid head (
g
V
z
g
p
H
2ρ
2
) may be brought about by a
change in pressure or velocity or both.
An impulse turbine (e.g. Pelton wheel; water wheel) is one where the change in head
is brought about primarily by a change in velocity. This usually involves unconfined
free jets of water (at atmospheric pressure) impinging on moving vanes.
A reaction turbine (e.g. Francis turbine; Kaplan turbine; windmill) is one where the
change in head is brought about primarily by a change in pressure.
2.2 Positive-Displacement and Dynamic pumps
Postive-displacement pumps operate by a change in volume; energy conversion is
intermittent. Examples in the human body include the heart (diaphragm pump) and the
intestines (peristaltic pump). In a reciprocating pump (e.g. a bicycle pump) fluid is sucked in
on one part of the cycle and expelled (at higher pressure) in another.
In dynamic pumps there is no change in volume and energy conversion is continuous. Most
pumps are rotodynamic devices where fluid energy is exchanged with the mechanical energy
of a rotating element (called a runner in turbines and an impeller in pumps), with a further
conversion to or from electrical energy.
This course focuses entirely on rotary devices.
Note that, for gases, pumps are usually referred to as fans (for low pressures), blowers or
compressors (for high pressures).
2.3 Radial, Axial and Mixed-Flow Devices
The terms radial and axial refer to the change in direction of flow through a rotodynamic
device (pump or turbine):
Radial Axial Mixed
4. Hydraulics 2 T4-4 David Apsley
In a centrifugal pump flow enters
along the axis and is expelled
radially. (The reverse is true for a
turbine.)
An axial-flow pump is like a propeller;
the direction of the flow is unchanged
after passing through the device.
A mixed-flow device is a hybrid device,
used for intermediate heads.
In many cases – notably in pumped-storage power stations – a device can be run as either a
pump or a turbine.
Inward-flow reaction turbine centrifugal pump (high head / low discharge)
(e.g. Francis turbine)
Propeller turbine axial-flow pump (low head / high discharge)
(e.g. Kaplan turbine; windmill)
Volute
'Eye' (intake)
Impeller vane
flow
rotation
Blades
Guide vanes
Hub
Blades
Guide vanes
Inlet Outlet
5. Hydraulics 2 T4-5 David Apsley
2.4 Common Types of Turbine
Pelton wheels are impulse turbines used in
hydroelectric plant where there is a very high head
of water. Typically, 1 – 6 high-velocity jets of
water impinge on buckets mounted around the
circumference of a runner.
Francis turbines are used in many large
hydropower projects (e.g the Hoover Dam), with an
efficiency in excess of 90%. Such moderate- to
high-head turbines are also used in pumped-storage
power stations (e.g. Dinorwig and Ffestiniog in
Wales; Foyers in Scotland), which pump water
uphill during periods of low energy demand and
then run the system in reverse to generate power
during the day. This smooths the power demands
on fossil-fuelled and nuclear power stations which
are not easily brought in and out of operation. Francis turbines are like centrifugal pumps in
reverse.
Kaplan turbines are axial-flow (propeller) turbines. In the
Kaplan design the blade angles are adjustable to ensure
efficient operation for a range of discharges.
Wells turbines were specifically developed for wave-energy applications. They have the
property that they rotate in the same direction irrespective of the flow direction.
Bulb generators are large-diameter variants of the Kaplan propeller turbine, which are
suitable for the low-head, high-discharge applications in tidal barrages (e.g. La Rance in
France). Flow passes around the bulb, which contains the alternator.
The Archimedes screw has been used since ancient
times to raise water. It is widely used in water
treatment plants because it can accommodate
submerged debris. Recently, several devices have been
installed beside weirs in the north of England to run in
reverse and generate power.
Jet
Bucket
Spear valve
6. Hydraulics 2 T4-6 David Apsley
3. Pump and System Characteristics
3.1 Pump characteristics
Pump characteristics are the head (H), input power (I) and efficiency (η) as functions of
discharge (Q). The most important is the H vs Q relationship. Typical shapes of these
characteristics are sketched below for centrifugal and axial-flow pumps.
Q
I
H
Q
I
H
centrifugal pump axial-flowpump
Given the pump characteristics at one rotation rate (N), those at different rotation rates may
be determined using the hydraulic scaling laws (Section 4).
Ideally, one would like to operate the pump:
as close as possible to the design point (point of maximum efficiency);
in a region where the H-Q relationship is steep; (otherwise there are significant
fluctuations in discharge for small changes in head).
3.2 System characteristics
In general the pump has to supply enough energy to:
lift water through a certain height – the static lift Hs;
overcome losses dependent on the discharge, Q.
Thus the system head is
lossess hHH
Typically, losses (whether frictional or due to pipe fittings) are proportional to Q2
, so that the
system characteristic is often quadratic:
2
aQHH s
The static lift is often decomposed
into the rise from sump to the level
of the pump (the suction head, Hs1)
and that between the pump and the
delivery point (Hs2). The first of
these is limited by the maximum
suction height (approximately 10 m,
corresponding to 1 atmosphere) and
will be discussed later in the context
of cavitation.
Sump
Delivery reservoir
Suction main
Delivery main
Static lift
Hs
Suction head
Pump
7. Hydraulics 2 T4-7 David Apsley
3.3 Finding the Duty Point
The pump operates at a duty point where the head supplied by the pump precisely matches
the head requirements of the system at the same discharge; i.e. where the pump and system
characteristics intersect.
Q
H
System
characteristic
Pump
characteristic
Duty
point
Hs
Example. (Examination 2005 – part)
A water pump was tested at a rotation rate of 1500 rpm. The following data was obtained. (Q
is quantity of flow, H is head of water, η is efficiency).
It is proposed to used this pump to draw water from an open sump to an elevation 5.5 m
above. The delivery pipe is 20.0 m long and 100 mm diameter, and has a friction factor of
0.005.
If operating at 1500 rpm, find:
(a) the maximum discharge that the pump can provide;
(b) the pump efficiency at this discharge;
(c) the input power required.
Answer: (a) 37.5 L s–1
; (b) 0.67; (c) 3.7 kW
In practice, it is desirable to run the pump at a speed where the duty point is close to that of
maximum efficiency. To do this we need to determine how the pump characteristic varies
with rotation rate N – see below.
Q (L s–1
) 0 10 20 30 40 50
H (m) 10.0 10.5 10.0 8.5 6.0 2.5
η 0.0 0.40 0.64 0.72 0.64 0.40
8. Hydraulics 2 T4-8 David Apsley
3.4 Pumps in Parallel and in Series
Pumps in Parallel
Same head: H
Add the discharges: Q1 + Q2
Advantages of pumps in parallel are:
high capacity: permits a large
total discharge;
flexibility: pumps can be
brought in and out of service if
the required discharge varies;
redundancy: pumping can
continue if one is not operating
due to failure or planned
maintenance.
Pumps in Series
Same discharge: Q
Add the heads: H1 + H2
Pumps in series may be necessary to
generate high heads, or provide
regular “boosts” along long pipelines
without large pressures at any
particular point.
Q
H
Single pump
Double the flow
Pumps in parallel
Q
H
Single pump
Pumps in series
Double
the
head
9. Hydraulics 2 T4-9 David Apsley
Example. (Examination, January 2004)
A rotodynamic pump, having the characteristics tabulated below, delivers water from a river
at elevation 102 m to a reservoir with a water level of 135 m, through a 350 mm diameter
cast-iron pipe. The frictional head loss in the pipeline is given by hf = 550 Q2
, where hf is the
head loss in m and Q is the discharge in m3
s–1
. Minor head losses from valves and fittings
amount to 50 Q2
in the same units.
Pump characteristics: Q is discharge, H is head, η is efficiency.
(a) Calculate the discharge and head in the pipeline (at the duty point).
If the discharge is to be increased by the installation of a second identical pump:
(b) determine the unregulated discharge and head produced by connecting the pump:
(i) in parallel;
(ii) in series;
(c) determine the power demand at the duty point in the case of parallel operation.
Answer: (a) 0.137 m3
s–1
and 44 m;
(b) (i) 0.185 m3
s–1
and 53.5 m; (ii) 0.192 m3
s–1
and 55.1 m; (c) 155 kW
Q (m3
s–1
) 0 0.05 0.10 0.15 0.20
H (m) 60 58 52 41 25
η (%) --- 44 65 64 48
10. Hydraulics 2 T4-10 David Apsley
4 Hydraulic Scaling
4.1 Dimensional Analysis
Provided that the mechanical efficiency is the same, the performance of a particular
geometrically-similar family of pumps or turbines (“homologous series”) may be expected to
depend on:
discharge Q [L3
T–1
]
pressure change ρgH [ML–1
T–2
]
power P [ML2
T–3
] (input for pumps; output for turbines)
rotor diameter D [L]
rotation rate N [T–1
]
fluid density ρ [ML–3
]
fluid viscosity μ [ML–1
T–1
]
(Rotor diameter may be replaced by any characteristic length, since geometric similarity
implies that length ratios remain constant. Rotation rate is typically expressed in either rad s–1
or rpm.)
Since there are 7 variables and 3 independent dimensions, Buckingham’s Pi Theorem yields a
relationship between 4 independent groups, which may be taken as (exercise):
31Π
ND
Q
, 222Π
DN
gH
, 533
ρ
Π
DN
P
, Re
μ
ρ
Π
2
4
ND
For fully-turbulent flow the dependence on molecular viscosity μ and hence the Reynolds
number (Π4) vanishes. Then, for geometrically-similar pumps with different sizes (D) and
rotation rates (N):
2
3
1
3
ND
Q
ND
Q
,
2
22
1
22
DN
gH
DN
gH
,
2
53
1
53
ρρ
DN
P
DN
P
For pumps (input power P, output power ρgQH), any one of Π1, Π2, Π3 may be replaced by
)(η
ρ
Π
ΠΠ
3
21
efficiency
P
gQH
The reciprocal of this would be used for turbines.
Example.
A ¼-scale model centrifugal pump is tested under a head of 7.5 m at a speed of 500 rpm. It
was found that 7.5 kW was needed to drive the model. Assuming similar mechanical
efficiencies, calculate:
(a) the speed and power required by the prototype when pumping against a head of 44 m;
(b) the ratio of the discharges in the model to that in the prototype.
Answer: (a) 303 rpm and 1710 kW; (b) Qm/Qp = 1/38.8 = 0.0258
11. Hydraulics 2 T4-11 David Apsley
4.2 Change of Speed
For the same pump (i.e. same D) operating at different speeds N1 and N2:
1
2
1
2
N
N
Q
Q
,
2
1
2
1
2
N
N
H
H
,
3
1
2
1
2
N
N
P
P
Thus,
NQ , 2
NH , 3
NP
(This might be expected, since Q velocity, whilst H energy velocity2
).
These are called the hydraulic scaling laws or affinity laws.
Speed Scaling Laws For a Single Pump
1
2
1
2
N
N
Q
Q
,
2
1
2
1
2
N
N
H
H
,
3
1
2
1
2
N
N
P
P
, 21 ηη
Given pump characteristics at one speed one can use the hydraulic scaling laws to deduce
characteristics at a different speed.
4.2.1 Finding the Duty Point at a New Pump Speed
Scale each (Q,H) pair on the original
characteristic at speed N1 to get the new
characteristic at speed N2; i.e.
1
1
2
2 Q
N
N
Q
, 1
2
1
2
2 H
N
N
H
Where this scaled characteristic intercepts the
system curve gives the new duty point.
Q
Systemcharacteristic
Newduty point
Hs
N1
N2
H
12. Hydraulics 2 T4-12 David Apsley
4.2.2 Finding the Pump Speed For a Given Duty Point (Harder)
To find the pump speed for a given
discharge or head plot a hydraulic-
scaling curve back from the required
duty point (Q2, H2) on the system
curve, at unknown speed N2:
2
22
Q
Q
H
H
Very important: the hydraulic
scaling curve is not the same as the
system curve.
Where the hydraulic scaling curve cuts the original characteristic gives a scaled duty point
(Q1, H1) and thence the ratio of pump speeds from either the ratio of discharges or the ratio of
heads:
1
2
1
2
Q
Q
N
N
or
1
2
2
1
2
H
H
N
N
Example.
Water from a well is pumped by a centrifugal pump which delivers water to a reservoir in
which the water level is 15.0 m above that in the sump. When the pump speed is 1200 rpm its
pipework has the following characteristics:
Pipework characteristics:
Discharge (L s–1
): 20 30 40 50 60
Head loss in pipework (m): 1.38 3.11 5.52 8.63 12.40
Pump characteristics:
Discharge (L s–1
): 0 10 20 30 40
Head (m): 22.0 21.5 20.4 19.0 17.4
A variable-speed motor drives the pump.
(a) Plot the graphs of the system and pump characteristics and determine the discharge at
a speed of 1200 rpm.
(b) Find the pump speed in rpm if the discharge is increased to 40 L s–1
.
Answer: (a) 32 L s–1
; (b) 1290 rpm
Q
Systemcharacteristic
Newduty point
Hs
N1
N2
Scaling curve
through
duty point
H
),( 22 HQ
),( 11 HQ
13. Hydraulics 2 T4-13 David Apsley
4.3 Specific speed
The specific speed (or type number) is a guide to the type of pump or turbine required for a
particular role.
4.3.1 Specific Speed for Pumps
The specific speed, Ns, is the rotational speed needed to discharge 1 unit of flow against 1 unit
of head. (For what “unit” means in this instance, see below.)
For a given pump, the hydraulic scaling laws give
constant
ND
Q
31Π , constant
DN
gH
222Π
Eliminating D (and choosing an exponent that will make the combination proportional to N):
4/3
2/1
4/1
3
2
2
1
)(Π
Π
gH
NQ
or, since g is constant, then at any given (e.g. maximum) efficiency:
constantldimensiona
H
NQ
)(4/3
2/1
The constant is the specific speed, Ns, when Q and H in specified units (see below) are
numerically equal to 1:
Specific speed (pump)
4/3
2/1
H
NQ
NS
Notes.
The specific speed is a single value calculated at the normal operating point (i.e. Q
and H at the maximum efficiency point for the anticipated rotation rate N).
With the commonest definition (in the UK and Europe), N is in rpm, Q in m3
s–1
, H in
m, but this is far from universal, so be careful.
In principle, the units of Ns are the same as those of N, which doesn’t look correct
from the definition but only because that has been shortened from
4/3
2/1
4/3
2/113
)m1(
)sm1(
H
NQNs
Because of the omission of g the definition of Ns depends on the units of Q and H. A
less-common (but, IMHO, more mathematically correct) quantity is the dimensionless
specific speed Kn given by
4/3
2/1
)(gH
NQ
Kn
If the time units are consistent then Kn has the same angular units as N (rev or rad).
High specific speed ↔ large discharge / small head (axial-flow device).
14. Hydraulics 2 T4-14 David Apsley
Low specific speed ↔ small discharge / large head (centrifugal device).
Approximate ranges of Ns are (from Hamill, 2011):
Type Ns
Radial (centrifugal) 10 – 70 large head
Mixed flow 70 – 170
Axial > 110 small head
Example.
A pump is needed to operate at 3000 rpm (i.e. 50 Hz) with a head of 6 m and a discharge of
0.2 m3
s–1
. By calculating the specific speed, determine what sort of pump is required.
Answer: Ns = 350; axial-flow pump
4.3.2 Specific Speed for Turbines
For turbines the output power, P, is more important than the discharge, Q. The relevant
dimensionless groups are
222Π
DN
gH
, 533
ρ
Π
DN
P
Eliminating D,
4/5
2/1
4/1
5
2
2
3
)(
)ρ/(
Π
Π
gH
NP
or, since ρ and g are usually taken as constant (there does seem to be a presumption that
turbines are always operating in fresh water) then at any given efficiency:
constantldimensiona
H
NP
)(4/5
2/1
The specific speed of a turbine, Ns, is the rotational speed needed to develop 1 unit of power
for a head of 1 unit. (For what “unit” means in this instance, see below.)
Specific speed (turbine)
4/5
2/1
H
NP
NS
Notes.
With the commonest definition (in the UK and Europe), N is in rpm, P in kW (note),
H in m, but, again, this is not a universal convention. As with pumps, the units of Ns
are the same as those of N.
As with pumps, a less-commonly-used but mathematically more acceptable quantity
is the dimensionless specific speed Kn, which retains the ρ and g dependence:
4/5
2/1
)(
)ρ/(
gH
NP
Kn
15. Hydraulics 2 T4-15 David Apsley
Kn has the angular units of N (revs or radians) – see Massey (2005).
High specific speed ↔ small head (axial-flow device)
Low specific speed ↔ large head (centrifugal or impulse device).
Approximate ranges are (from Hamill, 2001):
Type Ns
Pelton wheel (impulse) 12 – 60 very large head
Francis turbine (radial-flow) 60 – 500 large head
Kaplan turbine (axial-flow) 280 – 800 small head
16. Hydraulics 2 T4-16 David Apsley
5. Mechanics of Rotodynamic Devices
5.1 Centrifugal Pump
Fluid enters at the eye of the impeller and flows
outward. As it does so it picks up the tangential
velocity of the impeller vanes (or blades) which
increases linearly with radius (u = rω). At exit the
fluid is expelled nearly tangentially at high velocity
(with kinetic energy subsequently converted to
pressure energy in the expanding volute). At the
same time fluid is sucked in through the inlet to take
its place and maintain continuous flow.
The analysis makes use of rotational dynamics:
power = torque angular velocity
torque = rate of change of angular momentum
where angular momentum is given by “(tangential) momentum radius”.
The absolute velocity of the fluid is the vector sum of:
impeller velocity (tangential)
+
velocity relative to the impeller (parallel to the vanes)
Write:
u for the impeller velocity (u = rω)
w for the fluid velocity relative to the impeller
v = u + w for the absolute velocity
The radial component of absolute velocity is determined primarily
by the flow rate:
A
Q
vr
where A is the effective outlet area. The tangential part (also called
the whirl velocity) is a combination of impeller speed (u = rω) and
tangential component relative to the vanes:
βcoswuvt
Only vt contributes to the angular momentum.
With subscripts 1 and 2 denoting inlet and outlet respectively,
)(ρ 1122 rvrvQTtorque tt
)ωω(ρω 1122 rvrvQTpower tt
But head
gQ
power
H
ρ
, whilst ur ω . Hence:
Euler’s turbomachinery equation:
)(
1
1122 uvuv
g
H tt
2w
2β 1w
ω22 ru
ω11 ru
Vane
v,Resultant
w β
ωru
v
tv
rv
17. Hydraulics 2 T4-17 David Apsley
The pump is usually designed so that the initial angular momentum is small; i.e. vt1 ≈ 0. Then
22
1
uv
g
H t
Effect of Blade Angle
Because in the frame of the impeller the fluid leaves the blades in a direction parallel to their
surface, forward-facing blades would be expected to increase the whirl velocity vt whilst
backward-facing blades would diminish it.
Tangential and radial components of velocity:
A
Q
wvr βsin , βcoswuvt ,
Eliminating w:
βcot
A
Q
uvt
Hence, if inlet whirl can be ignored,
)βcot( 2
2
A
Q
u
g
u
H
This is of the form bQaH , where
H initially decreases with Q for backward-facing blades (β < 90°; cot β > 0)
H initially increases with Q for forward-facing blades (β > 90°; cot β < 0)
This gives rise to the typical pump characteristics shown. Of the two, the former (backward-
facing blades) is usually preferred because, although forward-facing blades might be
expected to increase whirl velocity and hence output head, the shape of the characteristic is
such that small changes in head cause large changes in discharge and the pump tends to
“hunt” for its operating point (pump surge).
Non-Ideal Behaviour
The above is a very ideal analysis. There are many sources of losses. These include:
leakage back from the high-pressure volute to the low-pressure impeller eye;
frictional losses;
“shock” or flow-separation losses at entry;
non-uniform flow at inlet and outlet of the impeller;
cavitation (when the inlet pressure is small).
Example.
A centrifugal pump is required to provide a head of 40 m. The impeller has outlet diameter
0.5 m and inlet diameter 0.25 m and rotates at 1500 rpm. The flow approaches the impeller
radially at 10 m s–1
and the radial velocity falls off as the reciprocal of the radius. Calculate
the required vane angle at the outlet of the impeller.
Answer: 9.7°
Q
H
90β
90β
90β
(backward-facing blades)
(forward-facing blades)
18. Hydraulics 2 T4-18 David Apsley
5.2 Pelton Wheel
A Pelton wheel is the most common type of impulse turbine. One
or more jets of water impinge on buckets arranged around a
turbine runner. The deflection of water changes its momentum
and imparts a force to rotate the runner.
The power (per jet) P is given by:
power = force (on bucket) velocity (of bucket)
Force F on the bucket is equal and opposite to that on the jet; by the momentum principle:
velocityinchangefluxmassfluidonforce )(
Because the absolute velocity of water leaving the bucket is the vector resultant of the runner
velocity (u) and the velocity relative to the bucket, the change in velocity is most easily
established in the frame of reference of the moving bucket.
Assuming that the relative velocity leaving the buckets
is k times the relative velocity of approach, v – u (where
k is slightly less than 1.0 due to friction):
)θcos1)((
)(θcos)(
kuv
uvuvkx-velocitychange in
where θ is the total angle turned (here, greater than 90°). The maximum force would be
obtained if the flow was turned through 180°, but the necessity of deflecting it clear of the
next bucket means that θ is typically 165°.
From the momentum principle:
)θcos1)((ρ kuvQF
The power transferred in each jet is then
)θcos1()(ρ kuuvQFuP
The velocity part of the power may be written
2
2
12
4
1
)()( uvvuuv
Hence, for a given jet (Q and v), the power is a maximum when the runner speed u is such
that vu 2
1 , or the runner speed is half the jet speed. (At this point the absolute velocity
leaving the runner at 180° would be 0 if k = 1, corresponding to a case where all the kinetic
energy of the fluid is transferred to the runner.) In practice, the runner speed u is often fixed
by the need to synchronise the generator to the electricity grid, so it is usually the jet which is
controlled (by a spear valve). Because of other losses the speed ratio is usually slightly less
than ½, a typical value being 0.46.
The jet velocity is given by Bernoulli’s equation, with a correction for non-ideal flow:
gHcv v 2
where H is the head upstream of the nozzle (= gross head minus any losses in the pipeline)
and cv is an orifice coefficient with typical values in the range 0.97– 0.99.
bucket
jet u
v
k(v-u)
v-u
19. Hydraulics 2 T4-19 David Apsley
Example.
In a Pelton wheel, 6 jets of water, each with a diameter of 75 mm and carrying a discharge of
0.15 m3
s–1
impinge on buckets arranged around a 1.5 m diameter Pelton wheel rotating at
180 rpm. The water is turned through 165° by each bucket and leaves with 90% of the
original relative velocity. Neglecting mechanical and electrical losses within the turbine,
calculate the power output.
Answer: 471 kW
6. Cavitation
Cavitation is the formation, growth and rapid collapse of vapour bubbles in flowing liquids.
Bubbles form at low pressures when the absolute pressure drops to the vapour pressure and
the liquid spontaneously boils. (Bubbles may also arise from dissolved gases coming out of
solution.) When the bubbles are swept into higher-pressure regions they collapse very
rapidly, with large radial velocities and enormous short-term pressures. The problem is
particularly acute at solid surfaces.
Cavitation may cause performance loss, vibration, noise, surface pitting and, occasionally,
major structural damage. Besides the inlet to pumps the phenomenon is prevalent in marine-
current turbines, ship and submarine propellers and on reservoir spillways.
The best way of preventing cavitation in a pump is to ensure that the inlet (suction) pressure
is not too low. The net positive suction head (NPSH) is the difference between the pressure
head at inlet and that corresponding to the vapour pressure:
g
pp cavinlet
ρ
NPSH
The net positive suction head must be kept well above
zero to allow for further pressure loss in the impeller.
The inlet pressure may be determined from Bernoulli:
lossheadHH sumpinletpump
f
atm
inlet
inlet
h
g
p
g
V
z
g
p
ρ2ρ
2
Hence,
finlet
atminlet
h
g
V
z
g
p
g
p
2ρρ
2
To avoid cavitation one should aim to keep pinlet as large as possible by:
keeping zinlet small or, better still, negative (i.e. below the level of water in the sump;
keeping V small (large-diameter pipes);
keeping hf small (short, large-diameter pipes).
The first also assists in pump priming.
Sump
pump inlet
zinlet
patm