Project of Hydraulic/Water Turbine

~Contents~ Hydraulic efficiency 1 Turbine & Defination 8 Maintenance 2 Classification of turbine 3 Types of water turbines Pelton wheel Francis Kaplan 4 Efficiency 5 Efficiency types Hydraulic efficiency Mechanical efficiency Volumetric efficiency Overall efficiency 6 Turbine Physics Points 7 Design and application of water turbine 8 Maintenance 9 History Pelton wheel history Francis history Kaplan history 10 End

Turbine Defination:-A water turbine is a rotary engine that takes energy from moving water. Water turbines were developed in the nineteenth century and were widely used for industrial power prior to electrical grids. Now they are mostly used for electric power generation. They harness a clean and renewable energy source.

~Classification of turbines~ The hydraulic turbines are classified according to the type of energy available at the inlet of the turbine, direction of flow through the vanes, head at the inlet of the turbine and specific speed of the turbines. Thus the followings are the important classification of the turbines 1. According to the type of energy at inlet: (a) Impulse turbine, and (b) Reaction turbine. 2. According to the direction of flow through runner: (a) Tangential flow turbine. (b) Radial flow turbine. (c) Axial flow turbine, and (d) Mixed flow turbine. 3. According to the head at the inlet .of turbine: (a) High head turbine, (b) Medium head turbine, and (c) Low head turbine. 4. According to the specific speed of the turbine: (a) Low specific speed turbine, (b) Medium specific speed turbine, and (c) High specific speed turbine.

Types of Water Turbine:- There are three types of main turbine and other are concept types turbine MAIN TYPE:- 1 Pelton wheel turbine 2 Francis turbine 3 Kaplan turbine OTHERS TYPES (concept types) > Propeller >Bulb >Tube >Straflo >Tyson >Gorlov (Freeflow types) >Water wheel >Archimedean screw turbine >Turgo >Michell-Banki (also known as the Crossflow.)

~Pelton wheel turbine~ The Pelton wheel is among the most efficient types of Water turbines. The Pelton wheel extracts energy from the impulse (Momentum) of moving water, as opposed to its weight like traditional overshot water wheel. Although many variations of impulse turbines existed prior to Pelton's design, they were less efficient than Pelton's design; the water leaving these wheels typically still had high speed, and carried away much of the energy. Pelton' paddle geometry was designed so that when the rim runs at ½ the speed of the water jet, the water leaves the wheel with very little speed, extracting almost all of its energy, and allowing for a very efficient turbine.

~Francis Turbine~ The Francis turbine is a type of water turbine that was developed in Lowell, MA. 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.

-:Kaplan Turbine:- The Kaplan turbine is a propeller-type water turbine which has adjustable blades. It was developed by the Austrian professor, who combined automatically-adjusted propeller blades with automatically-adjusted wicket gates to achieve efficiency over a wide range of flow and water level. 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. Kaplan turbines are now widely used throughout the world in high-flow, low-head power production.

~Efficiency~ Large modern water turbines operate at mechanical efficiencies greater than 90% (not to be confused with thermodynamic efficiency). In physics, mechanical efficiency is the effectiveness of a machine and is defined as------------------------- Mechanical efficiency is the ratio of work output to work input. It is often expressed as a percentage. While the efficiency of an ideal machine is 100 percent, an actual machine's efficiency will always be less than 100% because of the second law of thermodynamics, which states that the quality of energy will decay, eventually becoming heat. This means that some of the work put into the system is transformed (lost) into thermal energy (heat). In a mechanical system, friction is the most common means by which work is lost to heat. The actual mechanical advantage of a system is always less than the ideal mechanical advantage due to these losses. Another way to express mechanical efficiency is it is the ratio of actual mechanical advantage to ideal mechanical advantage. Creating a perpetual motion machine of the third kind would require 100 percent mechanical efficiency. By recycling the work output back to the work input, a perpetual motion machine could maintain its movement forever. In controlled environments, low friction mechanisms can come close to the ideal efficiency. However, to maintain a perfectly ideal mechanism, the temperature output must be the absolute zero, which is impossible to reach due to the third law of thermodynamics. Therefore, perfect mechanical efficiency can never be achieved.

~Efficiency types~ Efficiencies of a Turbine- The followings are the important efficiencies of a turbine. (a) Hydraulic Efficiency, Nh (b) Mechanical Efficiency, Nm . (c) Volumetric Efficiency, Nv and (d) Overall Efficiency, No (1) Hydraulic Efficiency (Nh)- It is defined as the ratio of power given by water to the runner of a turbine (runner is a rotating part of a turbine and on the runner vanes ace fixed) to the power supplied by the water at the inlet of the turbine. The power at the inlet of the turbine is more and this power goes on decreasing as the water flows over the vanes of the turbine due to hydraulic losses as the vanes ace not smooth. Hence the power delivered.to the runner of the turbine will be less than the power available at the inlet of the turbine. Thus, mathematically, the hydraulic efficiency of a turbine is written as------------------ Where, R.P. =Power delivered to runner i.e .. runner power W.P. = Power supplied at inlet of turbine and also called water power =WxH kW 1000

~Efficiency types~ Mechanical Efficiency (Nm)'- The power delivered by water to the runner of a turbine is transmitted to the shaft of the turbine. Due to mechanical losses, the power available at the shaft of the turbine is less than the power delivered to the runner of a turbine. The ratio of the power available at the shaft of the turbine (known as S.P. or B.P. ) to the power delivered to the runner is defined as mechanical efficiency. Hence. mathematically, it is written as Where, S.P.- The ratio of the power available at the shaft of the turbine R.P. =Power delivered to runner i.e .. runner power

~Efficiency types~ Volumetric Efficiency (Nv)’- The volume of the water striking the runner of a turbine is slightly less than the volume of the water supplied to the turbine. Some of the volume of the water is discharged to the tail race without striking the runner of the turbine. Thus the ratio of the volume of the water actually striking the runner to the volume of water supplied to the turbine is defined as volumetric efficiency. It is written as----------------------

~Efficiency types~ Overall Efficiency (No)'-It is defined as the ratio of power available at the shaft of the turbine to the power supplied by the water at the inlet of the turbine. It is written as Here is the final and overall efficiency of various turbine, that’s all about efficiency.

Turbine physics Points:- >Energy and initial jet velocity >Final jet velocity >Optimal wheel speed >Torque >Power >Efficiency >System components

~Design and application of water turbine~ Typical range of heads Hydraulic wheel turbine           0.2 < H < 4   (H = head in m) Archimedes' screw turbine           1 < H < 10 Kaplan           2 < H < 40    Francis         10 < H < 350 Pelton           50 < H < 1300 Turgo            50 < H < 250 Turbine selection is based mostly on the available water head, and less so on the available flow rate. In general, impulse turbines are used for high head sites, and reaction turbines are used for low head sites. Kaplan turbines with adjustable blade pitch are well-adapted to wide ranges of flow or head conditions, since their peak efficiency can be achieved over a wide range of flow conditions

~Maintenance~ A Francis turbine at the end of its life showing cavitation pitting, fatigue cracking and a catastrophic failure. Earlier repair jobs that used stainless steel weld rods are visible. Turbines are designed to run for decades with very little maintenance of the main elements; overhaul intervals are on the order of several years. Maintenance of the runners and parts exposed to water include removal, inspection, and repair of worn parts. Normal wear and tear includes pitting from cavitation, fatigue cracking, and abrasion from suspended solids in the water. Steel elements are repaired by welding, usually with stainless steel rods. Damaged areas are cut or ground out, then welded back up to their original or an improved profile. Old turbine runners may have a significant amount of stainless steel added this way by the end of their lifetime. Elaborate welding procedures may be used to achieve the highest quality repairs. Other elements requiring inspection and repair during overhauls include bearings, packing box and shaft sleeves, servomotors, cooling systems for the bearings and generator coils, seal rings, wicket gate linkage elements and all surfaces.

History Water wheels have been used for thousands of years for industrial power. Their main shortcoming is size, which limits the flow rate and head that can be harnessed. The migration from water wheels to modern turbines took about one hundred years. Development occurred during the Industrial revolution, using scientific principles and methods. They also made extensive use of new materials and manufacturing methods developed at the time. History of pelton wheel :- The Pelton wheel is among the most efficient types of water turbines. It was invented by Lester Allan Pelton in the 1870s. The Pelton wheel extracts energy from the impulse momentum of moving water, as opposed to its weight like traditional overshot water wheel.

~History~ History of Francis turbine:- The Francis turbine is a type of water turbine that was developed by American Engineer James B. Francis in 1815-1892 of Lowell, MA. 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.

~History~ History of kaplan turbine :- The Kaplan turbine is a propeller-type water turbine which has adjustable blades. It was developed in 1913 by the Austrian professor Viktor Kaplan, who combined automatically-adjusted propeller blades with automatically-adjusted wicket gates to achieve efficiency over a wide range of flow and water level. 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. Kaplan turbines are now widely used throughout the world in high-flow, low-head power production.

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