Design, Construction and Testing of an Outward Radial-flow Reaction Water Turbine
CHAPTER ONE
Objectives of the Study
Given that there is increasing need to find other sources of energy and the fact that a sprinkler is the simplest form of a reaction water turbine, it is necessary to devise a means by which electricity could be generated from the sprinkler heads. In view of the importance of lighting the places that sprinklers are used when it is dark, use of other power sources rather than the sprinkler head will be eliminated. The objective of this research is therefore to review the design of a simple outward flow reaction water turbine and develop it to serve as a water sprinkler as well as a source of mechanical power for driving an electric dynamo for the generation of electricity to lighten up the place it is used when it is dark whenever there is water in the supply mains. Test is also to be carried out to ascertain the efficiencies of the device under various water pressures.
CHAPTER TWO
LITERATURE REVIEW
Introduction
The word turbine was coined in 1828 by Claude Burdin (1790-1873) to describe the subject of an engineering competition for a water power source. [Calvert
J.B (2003).] It comes from Latin word turbo, meaning a “whirling” or a “vortex”, and by extension a child’s top or a spindle. Defining a turbine as a rotating machine for deriving power from water is not quite exact. The precise definition is a machine in which the water moves relatively to the surfaces of the machine, as distinguished from machines in which such motion is secondary, as with a cylinder and piston. The common water wheel is a rotating machine, but not a turbine. Many types of prime movers are discussed in this report, but mainly turbines, the fundamental theory of which is explained. The disadvantage of energy from water is that it is strictly limited, and widely distributed in small amounts that are difficult to exploit. Only where a lot of water is gathered in a large river, or where descent is rapid, it is possible to take economic advantage. Most of these possibilities are quite small, as are the hydropower sites along the fall line on the Atlantic coast of the United States, or on the slopes of the pennies in England. These were developed in the early days of the Industrial Revolution, but are now abandoned because their scale is not the scale of modern industry. Each site provided a strictly limited horsepower, and in the autumns the water often failed. For expansion and reliability, all were rapidly replaced by steam engines fueled by coal, which were expandable and reliable. Today, hydropower usually means a large project on a major river, with extensive environmental damage. The fall in head is provided by a dam, which creates a lake that will be of limited life, since geological processes hate lakes and destroy them as rapidly as possible.
Niagara Falls, east of central North America in western New York and southeastern Ontario, forming part of the U.S-Canadian boundary is an excellent example of a hydropower site. It is unique; there is only one, and hardly anything else similar. The Niagara River carries the entire discharge of the Great Lakes, about 5520m3/s, and the concentrated elevation difference is about 50m. The visible falls carry nothing like this much water today; most is used for power. Hydropower could destroy the falls as a sublime view; we are lucky it has not. The power available from this discharge and drop is 3.6×106hp. The figures given in the encyclopedia for the power available from the Canadian and U.S. power projects on each side add up to considerably more than this. Perhaps they use more drop, or perhaps they are just optimistic. The first large-scale hydropower development here was in 1896. This was also the site of Nikola Tesla’s two-phase plant that pioneered polyphase power in the U.S. For comparison, the more than 190 million registered motor vehicles in the U.S.
CHAPTER THREE
GENERAL DESIGN THEORY AND CALCULATIONS
The Euler Turbine Equation
The real flow through a rotor is three dimensional, that is to say the velocity of the fluid is a function of three positional coordinates, say, in the cylindrical system, r,q and z, as shown in Fig. 3.1. Thus, there is a variation of velocity not only along the radius but also across the blade passage in any plane parallel to the rotor rotation, say from the upper side of one blade to the underside of the adjacent blade, which constitutes an abrupt change – a discontinuity. Also, there is variation of velocity in the meridional plane, i.e. along the axis of the rotor. The velocity distribution is, therefore, very complex and dependent upon the number of blades, their shapes and thicknesses, as well as on the width of the rotor and its variation with radius.
CHAPTER FOUR
CONSTRUCTION OF THE OUTWARD RADIAL FLOW REACTION WATER TURBINE
Introduction
Machine design consists of the application of scientific principles to the practical constructive act of engineering with the object of expressing original ideas in the form of drawing.
A designer is a person who solves problems. A good designer needs a wide knowledge of the subject of:
- Applied mechanics to find forces, speeds and acceleration;
- Strength of materials to calculate dimension, Stiffness and stability;
- Metallurgy for selection of materials;
- Engineering manufacture to determine methods of casting, forging, and heat treatment;
CHAPTER FIVE
TESTS AND RESULTS
CHAPTER SIX
SUMMARY
Considering where reaction water turbines (i.e. sprinklers) are used, lighting the places will greatly enhance the working time and ease working at the places at night. The residual power head was used to rotate a dynamo and generate electricity thereby eliminating the use of power from other sources that are costlier and not as environmental friendly.
Literature showed that Pelton impulse turbine, Francis Turbine and Kaplan turbine had been satisfactorily designed based on Euler theory and accepted universally.
CONCLUSION
The objective of this research to design, construct and test an outward radial flow reaction water turbine was achieved.
In producing this turbine, materials were sourced and bought locally. Fabrication and assembly of various parts of the turbine were carried out at machine tools shop and foundries within Zaria. The cost of materials used in fabricating the turbine stood at thirty five thousand, three hundred and eighty naira only (N 35,380.00). This cost would be greatly reduced when this turbine is mass produced.
RECOMMENDATION
In view of the fact that there is continuous need to look for other sources of energy and perseverance is the key to getting better results knowing that quality is a journey not a destination, the following are recommended:
- A speed multiplying mechanism could be introduced between the pinions of the rotor and the dynamo to get higher speeds with the same pressure to increase the power
- The rotor arms could be made from aluminium alloy casting, the base plate and dynamo carrier support made from 10mm mild steel plate to reduce the weight and cost of materials in order to produce a cheaper water turbine.
- The leakage within the rotor bearing and the supply end assembly should be reduced as much as possible to minimize losses in power
- The design could be simulated using available computational fluid dynamics software to get optimum performance at lower pressures and to also to validate the experimental result
REFERENCES
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- Date visited: 17th January, 2007.
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