Chapter 5 1. Hydraulic Turbines (Gorla & Khan, pp )

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Electronic Notes Chapter 5 1. Hydraulic Turbines (Gorla & Khan, pp.91 141) 1.

serve 1.3 million people. Reference: http://www.greennews.com/hydropower.asp Draft (Tailrace) tube Draft tube Tailrace Tailrace.

wikipedia.org/wiki/pelton_wheel http://en.wikipedia.org/wiki/kaplan_turbine Reading/watching materials (Ocean hydroelectricity): http://www.

youtube.com/watch?vcel7yc8r4k&featurerelated http://www.youtube.com/watch?vwvxuzf4lvgw&featurerelated http://www.youtube.com/watch?vfvyactjpmvk&featurerelated http://www.

1 Electronic Notes Chapter 5 1. Hydraulic Turbines (Gorla & Khan, pp ) 1. Terminologies Related to A Hydropower Plant Hoover Dam generates more than 4 billion kilowatt-hours of electricity each year, enough to serve 1.3 million people. Reference: Draft (Tailrace) tube Draft tube Tailrace Tailrace. Impulse and Reaction Turbines Reading/watching materials (Hydraulic turbines): Reading/watching materials (Ocean hydroelectricity): V9DSew&featurerelated Reading/watching materials (River hydroelectricity): izmbE&featurerelated 1

.1 Impulse Hydraulic Turbines Impulse turbines change the velocity of

The jet impinges on the turbine's curved blades which change the

The resulting change in momentum (impulse) causes a force on the

Since the turbine is spinning, the force acts through a distance

Prior to hitting the turbine blades, the water's pressure (potential

2 .1 Impulse Hydraulic Turbines Impulse turbines change the velocity of a water jet flow. The jet impinges on the turbine's curved blades which change the direction of the flow. The resulting change in momentum (impulse) causes a force on the turbine blades. Since the turbine is spinning, the force acts through a distance (work) and the diverted water flow is left with diminished energy. Prior to hitting the turbine blades, the water's pressure (potential energy) is converted to kinetic energy by a nozzle and focused on the turbine. No pressure change occurs at the turbine blades, and the turbine doesn't require a housing for operation. Impulse turbines are most often used in very high head (>300m/984ft) applications. Consequently, the size of an impulse turbine can be compact. Examples of Impulse Hydraulic Turbines (Pelton Turbines/Wheels)

Lester Allan Pelton (Sept. 5, 189 Mar. 14, 1908) Pelton made his living as a carpenter and a millwright. He created the most efficient form of impulse water turbine. Viktor Kaplan (Nov.

. Reaction Hydraulic Turbines Reaction turbines are acted on by water, which changes pressure as it moves through the turbine and gives up its energy.

Most water turbines in use are reaction turbines and are used in low (<30m/98ft) and medium (30 300m/98 984ft) head applications.

3 Lester Allan Pelton (Sept. 5, 189 Mar. 14, 1908) Pelton made his living as a carpenter and a millwright. He created the most efficient form of impulse water turbine. Viktor Kaplan (Nov. 7, 1876 Aug 3, 1934) Kaplan was an Austrian engineer and the inventor of the Kaplan turbine. James Bicheno Francis (May 18, 1815 Sept. 18, 189) Francis was a British-American engineer.. Reaction Hydraulic Turbines Reaction turbines are acted on by water, which changes pressure as it moves through the turbine and gives up its energy. They must be encased to contain the water pressure (or suction), or they must be fully submerged in the water flow. In reaction turbines, pressure drop occurs in both fixed and moving blades. Most water turbines in use are reaction turbines and are used in low (<30m/98ft) and medium (30 300m/98 984ft) head applications. For this reason, the size of a reaction turbine is usually larger than an impulse turbine (the latter of which is used for high head applications). Typical reaction hydraulic turbines include: Kaplan turbines and Francis turbines. The Francis turbine is a type of water turbine that was developed by James B. Francis. It is an inward flow reaction turbine that combines radial and axial flow concepts. Francis turbines are the most common water turbine in use today. They operate in a head range of ten meters to several hundred meters and are primarily used for electrical power production. The Kaplan turbine is a propeller type water turbine which has adjustable blades. It was developed in 1913 by the Austrian professor Viktor Kaplan. Kaplan turbines are now widely used throughout the world in high flow, low head power production. The Kaplan turbine was an evolution of the Francis turbine. Its invention allowed efficient power production in low head applications that was not possible with Francis turbines. A Kaplan turbine is used where a large quantity of water is available at low heads and hence the blades must be long and have large chords so that they are strong enough to transmit the very high torque that arises. Reading/watching materials:

4 Examples of Reaction Hydraulic Turbine (Francis Turbines/Wheels) Francis runner, Three Gorges Dam Guide vanes at full flow setting Francis Inlet Scroll, Grand Coulee Dam Small Swiss made Francis turbine 4

5 Examples of Reaction Hydraulic Turbine (Kaplan Turbines/Wheels) 5

6 Comparison the Pelton, Francis and Kaplan Turbines Leakage in a hydraulic turbine Schematic layout of hydro plant (revised from Fig.3.3 from Gorla and Khan) h f H 1 H A concept related to Pelton turbines: Bucket Jet Speed Ratio (Blade Jet Speed Ratio): U Bucket Speed R C Jet Speed 1 Pelton wheel (losses and efficiencies) Concepts: pipe line transmission efficiency, jet efficiency, mechanical efficiency, and overall efficiency. Pipe line transmission efficiency (to reflect losses in the penstock due to viscous fluid frictions and turbulence) Energy at the end of pipe H1 hf H η tr Energy available at reservoir H1 H1 The nozzle efficiency Energy at the nozzle outlet C1 η j Energy at the nozzle inlet gh Nozzle velocity coefficient Actual jet velocity C1 C V Theoretical jet velocity gh Therefore, η. j C V (pp.95, Gorla and Khan) 6

Chapter 5 1. Hydraulic Pumps (pp , Gorla & Khan; Wiki)

Chapter 5 1. Hydraulic Pumps (pp. 47 90, Gorla & Khan; Wiki) 1. Two Basic Categories of Pumps Positive Displacement (PD) Pumps A positive displacement pump causes a fluid to move by trapping a fixed amount