ii
"Then when you have finished the prayer,
remember Allah standing and sitting
and reclining; but when you are secure
(from danger) keep up prayer."
[Surah An-Nisaa: Ayah 103]
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Mini Hyadropower Generation System-Advanced Physics-Project Report, Study Guides, Projects, Research of Advanced Physics
This project is related to Physics and cover its multiple concepts. It was submitted to Sir Ahmad Yasir at Bengal Engineering and Science University. It includes: Mini-hydropower, Generation, System, Classification, Turbines, Impulse, Reaction, Waterwheel, Channel
Typology: Study Guides, Projects, Research
2011/2012
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ii
"Then when you have finished the prayer,
remember Allah standing and sitting
and reclining; but when you are secure
(from danger) keep up prayer."
[Surah An-Nisaa: Ayah 103]
vii
Table of Contents
Acknowledgments .................................................................................................... vi
Table of Contents .................................................................................................... vii
List of Figures .......................................................................................................... xi
List of Tables.......................................................................................................... xiii
Abstract .................................................................................................................. xiv
1 Introduction ....................................................................................................... 1
1.1 History of Water Turbine Technology ........................................................ 1 1.2 Scope of Project ......................................................................................... 2
2 Hydropower ....................................................................................................... 3
2.1 Classification of Hydropower ..................................................................... 3 2.2 Uses of Hydropower .................................................................................. 3 2.3 Benefits of Mini Hydro Power.................................................................... 4 2.4 Power Needs .............................................................................................. 4 2.5 Water Power .............................................................................................. 4 2.6 Suitable Conditions for Hydro power ......................................................... 6
3 Turbines............................................................................................................. 7
3.1 Classifications of Hydraulic Turbines ......................................................... 7 3.1.1 Impulse Turbines .................................................................................... 8 3.1.2 Reaction Turbines .................................................................................. 9 3.2 Turbine Selection ....................................................................................... 9 3.2.1 Turbine Selection on the Basis of Specific Speed ................................... 9 3.3 Turbine Model Testing ............................................................................. 10
4 Waterwheel...................................................................................................... 12
4.1 The Development of Modern Waterwheels............................................... 12 4.2 Types of Waterwheels .............................................................................. 14
xiii
- 4.2.1 Overshot Waterwheel - 4.2.2 Performance Characteristics - 4.2.3 Breast Shot Waterwheel - 4.2.4 Undershot Waterwheel - 4.2.5 Impulse or Stream Wheels - 4.3 Stream Wheels in Rectangular Channels
- 4.4 Design of Waterwheel
- 4.5 Shaft Design.............................................................................................
- 4.5.1 Criteria for Shaft Design.......................................................................
- 4.6 Bearing Selection
- 5 Open Channel Design
- 5.1 Channel Design Process
- 5.2 Channel Linings
- 5.3 Manning‟s Roughness Coefficient, n
- 5.3.1 Linings with Constant Manning‟s Roughness Coefficient
- 5.3.2 Linings with n Varying with Flow Depth
- 5.4 Maximum Permissible Velocities, Vmax
- 5.5 Maximum Allowable Shear Stress or Tractive Force, τall
- 5.6 Selecting Channel Linings
- 6 Discharge Measurement
- 6.1 Measurement of Discharge by Velocity Area Method...............................
- 6.1.1 Segmentation........................................................................................
- 6.1.2 Measurement of Area
- 6.1.3 Measurement of Velocity
- 6.1.4 Measurement of Velocity by Current Meter
- 6.1.5 Measurement of Velocity by Floats
- 6.2 Slope-Area Method
- 6.1 Measurement of Discharge by Velocity Area Method...............................
- 7 Hydro Kinetic Turbines
- 7.1 Rotor Configurations
- 7.1.1 Horizontal Axis Turbines ix
- 7.1.2 Cross Flow Turbines
- 7.1.3 Vertical Axis Turbines
- 7.2 Rotor Placement Options
- 7.2.1 Energy Capture
- 7.2.2 Competing Users
- 7.2.3 Construction Challenge
- 7.2.4 Design and Operational Constraints
- Turbines 7.3 Technical Advantages and Disadvantages of Horizontal and Vertical
- 7.4 Advantages of Vertical Axis Turbines
- 7.4.1 Design Simplicity
- 7.4.2 Generator Coupling
- 7.4.3 Flotation and Augmentation Equipment
- 7.4.4 Noise Emission
- 7.4.5 Skewed Flow
- 7.5 Disadvantages of Vertical Axis Turbines
- 7.6 Advantages of Horizontal Axis Turbines
- 7.6.1 Knowledgebase
- 7.6.2 Performance
- 7.6.3 Control
- 7.6.4 Annular Ring Augmentation Channels
- 7.7 Disadvantages of Horizontal Axis Turbines
- 7.8 Open Turbines Operation
- 7.9 Energy from Water
- 7.10 Darrieus Turbine
- 7.10.1 Velocity and Force Diagram
- 7.11 Tip Speed Ratio........................................................................................
- 7.12 Selecting Blade Chord and Profile
- 7.13 Angle of Attack
- 8 Velocity Increasing Parshall Flume x
- 8.1 Open Channel Hydraulics
- 8.2 Specific Energy
- 8.3 Characteristic of Critical Flow
- 8.4 Froude Number and Critical Flow
- 8.5 Theory Applied to Flumes
- 8.5.1 General Discharge Versus Head Formula
- 8.5.2 Parshall Flume......................................................................................
- 8.6 Velocity Increasing Flume........................................................................
- 9 Design Calculations
- 9.1 Design of Water wheel for Hydraulic Bench Apparatus
- 9.2 Design of Artificial Open Channel and Waterwheel
- 9.3 Shaft Design.............................................................................................
- 9.4 Discharge of Soan River
- 9.5 Design of Parshall Flume
- Summary and Conclusions
- Future Recommendations
- References
- Appendix
- Vita
- Figure 2.1.Layout of a typical micro hydro scheme --------------------------------------- List of Figures
- Figure 3.1.Normal Range of operation by turbines ---------------------------------------
- Figure 4.1.Waterwheel with buckets -------------------------------------------------------
- Figure 4.2.Water wheel ----------------------------------------------------------------------
- Figure 4.3.Overshoot wheel using potential energy to generate electricity ------------
- Figure 4.4.Overshoot waterwheel -----------------------------------------------------------
- Figure 4.5.Efficiency curve for overshoot waterwheel -----------------------------------
- Figure 4.6.Breasts shoot water wheel ------------------------------------------------------
- Figure 4.7.Efficiency as a function of flow rate -------------------------------------------
- Figure 4.8.Working principle of undershoot waterwheel --------------------------------
- Figure 4.9.Stream wheel ---------------------------------------------------------------------
- Figure 4.10.Loads applied to shaft ----------------------------------------------------------
- Figure 5.1.Manning's roughness coefficient for rip rap lined channels -----------------
- Figure 5.2.Allowable tractive force for non cohesive soils ------------------------------
- Figure 5.3.Channel lining selection ---------------------------------------------------------
- Figure 6.1.River cross section ---------------------------------------------------------------
- Figure 6.2.Typical locations for measuring discharge by current meter ----------------
- Figure 6.3.General setup for measuring velocity ------------------------------------------
- Figure 7.1.Classification of turbine rotors -------------------------------------------------
- Figure 7.2.Horizontal axis turbines ---------------------------------------------------------
- Figure 7.3.Vertical axis turbines ------------------------------------------------------------
- Figure 7.4.Turbine mounting options-------------------------------------------------------
- Figure 7.5.Power coefficient versus upstream and downstream velocity ratios -------
- Figure 7.6.Darrieus turbine ------------------------------------------------------------------
- Figure 7.7.Darrieus turbine arrangement ---------------------------------------------------
- Figure 7.8.Blade shape of darrieus turbine ------------------------------------------------
- Figure 7.9.Velocity and force diagram -----------------------------------------------------
- Figure 7.10.Velocity diagram ---------------------------------------------------------------
- Figure 7.11.Darrieus turbine with three blades --------------------------------------------
- Figure 7.12.Lift and drag coefficients for darrieus turbine-------------------------------
- Figure 7.13.Velocity triangles ---------------------------------------------------------------
- Figure 7.14.Normal and tangential forces-------------------------------------------------- xii
- Figure 8.1.Energy in flowing fluid----------------------------------------------------------
- Figure 8.2.Specific energy curve ------------------------------------------------------------
- Figure 8.3.Flow through sluice gate --------------------------------------------------------
- Figure 8.4.Parshall flume --------------------------------------------------------------------
- Figure 8.5.Parshall flume dimensions ------------------------------------------------------
- Figure 8.6.Cross sectional view of velocity increasing parshall flume -----------------
- Figure 8.7.Top view of velocity increasing parshall flume with water turbine --------
- Figure.9.1.Calculation of number of blades from trigonometry -------------------------
- Figure 9.2.Waterwheel -----------------------------------------------------------------------
- Figure 9.3.Waterwheel with vanes location in water -------------------------------------
- Figure 9.4.Trignometric relation for number of blades -----------------------------------
- Figure 9.5.Waterwheel and channel --------------------------------------------------------
- Figure 9.6.Soan river profile ----------------------------------------------------------------
- Figure 9.7.Soan river profile ----------------------------------------------------------------
- Figure 9.8.Cross sectional view of velocity increasing parshall flume -----------------
- Figure 9.9.Designed parshall flume of one foot throat -----------------------------------
- Figure 9.10.Parshall flume -------------------------------------------------------------------
- Table 2.1.Classification of hydropower by size List of Tables
- Table 2.2.Power needs of a house
- Table 3.1.Classification of water turbines
- Table 3.2.Turbine selection
- Table 7.1.Comparison of horizontal and vertical axis turbines
- Table 9.1.Dimensions of designed channel
- Table 9.2.Area of different sections of soan river
- Table 9.3.Area of different sections of soan river
- Table 9.4.Dimensions of three feet parshall flume
- Table 9.5.Dimension of one foot parshall flume
- Table A.1.Mechanical properties of different materials
- Table A.2.Flow measuring formulae for Parshall flume
- Table A.3.Widths of segments for measurements of depths and velocities in canals
1 Introduction
1.1 History of Water Turbine Technology
Experiments on the mechanics of reaction wheels conducted by the Swiss mathematician Leonhard Euler and his son Albert in the 1750s found application about 75 years later. In 1826 Jean-Victor Poncelet of France proposed the idea of an inward-flowing radial turbine, the direct precursor of the modern water turbine. This machine had a vertical spindle and a runner with curved blades that was fully enclosed. Water entered radially inward and discharged downward below the spindle. A similar machine was patented in 1838 by Samuel B. Howd of the United States and built subsequently. Howd's design was improved on by James B. Francis, who added stationary guide vanes and shaped the blades so that water could enter shock-free at the correct angle. His runner design, which came to be known as the Francis turbine, is still the most widely used for medium-high heads. Improved control was proposed by James Thomson, a Scottish engineer, who added coupled and pivoted curved guide vanes to assure proper flow directions even at part load.
A radial outward-flow turbine had been proposed in 1824 by the French engineering professor Claude Burdin and his former student Benoit Fourneyron. This device had a vertical axis carrying a runner with curved blades through which the water left almost tangentially. Fixed guide vanes, curved in the opposite direction, were mounted in an annulus inside the runner. Unfortunately the design made it difficult to support the runner and to take power off the turbine wheel. The first successful version of the turbine was built by Fourneyron in 1827. More than 100 such machines were subsequently built all over the world; they achieved efficiencies up to 75 percent at full load with heads up to 107 meters. In 1844 Uriah A. Boyden added an outlet diffuser to recover part of the kinetic energy exiting the device and thereby further improved efficiency. Outward-flow turbines, however, are inherently unstable, and speed control is difficult. Moreover, the construction of outward-flow turbines is very complex as compared to that of Francis-type runners, and this fact led to their eventually being supplanted by the latter.
Francis turbines were augmented by the development of the Pelton wheel for small flow rates and high heads and by propeller turbines, first built by Kaplan in
1913, for large flows at low heads. Kaplan's variable-pitch propeller turbine, which still bears his name, was manufactured after 1920. These units, together with the Deriaz mixed-flow turbine (invented in 1956), constitute the arsenal of modern water turbines. By the mid-19th century, water turbines were widely used to drive sawmills and textile mill equipment, often through a complex system of gears, shafts, and pulleys. After the widespread adoption of the steam engine they did not, however, become a major factor in power generation until the advent of the electric generator made hydroelectric power possible.
1.2 Scope of Project
Pakistan has 79 million acres of which about 35 million acres are canal commanded. The canal water and river water have a lot of energy which can be utilized for electricity production. Water turbines can be installed on these canals and rivers and electricity can be produced. In flat areas water wheel can be installed on canals and rivers for electricity production and other mechanical works. Mechanically water wheel can run a water pump and in water logging areas they can pump out water which can be used for irrigation purpose. Pakistan has large potential for mini hydropower where rivers and canals are not too steep. In these areas water energy can be utilized for electricity production.
and using it to accomplish physical work. Electrical use implies the generation of electricity from turbine or waterwheel and using it to perform work.
2.3 Benefits of Mini Hydro Power
Many benefits may be obtained from small scale hydro power including [3]. Emissions-free electricity production Unlike wind turbines, hydro power can potentially generate electricity consistently Long-proven and reliable technology Does not generate air pollution No waste disposal No fuel cost involves.
2.4 Power Needs
Power needs of any home vary depending upon usage. Average power usage of an average house is given in table 2.2 [4]. Table 2.2.Power needs of a house Appliances Watts/hour Hours/week Watt/hours/week Washing machine 360 2 (four loads) 720 Vacuum cleaner 700 1 700 Sewing machine 100 1 100 Clothing Iron 1000 25 250 Ceiling fan 50 40 2000 Computer 150 40 6000 19" color TV 70 14 980 VCR 40 2 80 CD player/Stereo 35 21 735 Fluorescent lights 16 5 400 2800
2.5 Water Power
The energy available in flowing water depends on the volume of water flowing per second and the height (head) that the water falls. The conversion of this energy into
electricity will depend upon the combined efficiency of the components listed above; the efficiency of a small hydro scheme can be between 50-85%.Water Power can be harnessed in many ways; tidal flows can be utilized to produce power by building a barrage across an estuary and releasing water in a controlled manner through a turbine; large dams hold water which can be used to provide large quantities of electricity; wave power is also harnessed in various ways. It is a technology that has been utilized throughout the world, by a diverse range of societies and cultures, for many centuries. Micro-hydro power is the small-scale harnessing of energy from falling water; for example, harnessing enough water from a local river to power a small factory or village. This fact sheet will concentrate mainly at micro-hydro power.
Figure 2.1 shows the main components of a run-of-the-river micro-hydro scheme. This type of scheme requires no water storage but instead diverts some of the water from the river which is channeled along the side of a valley before being „dropped‟ into the turbine via a penstock. In figure 2.1, the turbine drives a generator that provides electricity for a workshop. The transmission line can be extended to a local village to supply domestic power for lighting and other uses [4].
Figure 2.1.Layout of a typical micro hydro scheme
3 Turbines
A turbine converts the energy in falling water into shaft power. There are various types of turbine which can be categorized in one of several ways. The choice of turbine will depend mainly on the pressure head available and the design flow for the proposed hydropower installation. As shown in table 2 below, turbines are broadly divided into three groups; high, medium and low head, and into two categories: impulse and reaction [2].
Table 3.1.Classification of water turbines Type Hydraulic Head
Turbine Runner
High Medium Low
Impulse Pelton Turgo Multi-jet Pelton
Cross flow Turgo Multi-jet Pelton
Cross flow
Reaction Francis Pump-as-turbine (PAT)
Propeller Kaplan
3.1 Classifications of Hydraulic Turbines
Water turbines are generally divided into two categories: Impulse turbines used for high heads of water and low flow rates Reaction turbines normally employed for heads below about 450 meters and moderate or high flow rates. These two classes include the main types in common use namely, the Pelton impulse turbine and the reaction turbines of the Francis, propeller, Kaplan, and Deriaz variety. Turbines can be arranged with either horizontal or, more commonly, vertical shafts. Wide design variations are possible within each type to meet the specific local hydraulic conditions. Today, most hydraulic turbines are used for generating electricity in hydroelectric installations [5].
3.1.1 Impulse Turbines
In an impulse turbine the potential energy, or the head of water, is first converted into kinetic energy by discharging water through a carefully shaped nozzle. The jet, discharged into air, is directed onto curved buckets fixed on the periphery of the runner to extract the water energy and convert it to useful work. Modern impulse turbines are based on a design patented in 1889 by the American engineer Lester Allen Pelton. The free water jet strikes the turbine buckets tangentially. Each bucket has a high centre ridge so that the flow is divided to leave the runner at both sides. Pelton wheels are suitable for high heads, typically above about 450 meters with relatively low water flow rates. For maximum efficiency the runner tip speed should equal about one-half the striking jet velocity. The efficiency (work produced by the turbine divided by the kinetic energy of the free jet) can exceed 91 percent when operating at 60–80 percent of full load.
The power of a given wheel can be increased by using more than one jet. Two- jet arrangements are common for horizontal shafts. Sometimes two separate runners are mounted on one shaft driving a single electric generator. Vertical-shaft units may have four or more separate jets. If the electric load on the turbine changes, its power output must be rapidly adjusted to match the demand. This requires a change in the water flow rate to keep the generator speed constant. The flow rate through each nozzle is controlled by a centrally located, carefully shaped spear or needle that slides forward or backward as controlled by a hydraulic servomotor. Proper needle design assures that the velocity of the water leaving the nozzle remains essentially the same irrespective of the opening, assuring nearly constant efficiencies over much of the operating range. It is not prudent to reduce the water flow suddenly to match a load decrease. This could lead to a destructive pressure surge (water hammer) in the supply pipeline, or penstock. Such surges can be avoided by adding a temporary spill nozzle that opens while the main nozzle closes or, more commonly, by partially inserting a deflector plate between the jet and the wheel, diverting and dissipating some of the energy while the needle is slowly closed. Another type of impulse turbine is the turgo type. The jet impinges at an oblique angle on the runner from one side and continues in a single path, discharging at the other side of the runner. This type of turbine has been used in medium-sized units for moderately high heads [6].
turbine designed to deliver 100,000 horsepower (74,600 kilowatts) with a head of 40 feet (12.2 meters) operating at 72 revolutions per minute would have a specific speed of 226, suggesting a propeller or Kaplan turbine. Turbine Selection is on the basis of head [8].
There are several basic types of turbines, each operates most effectively in a certain pressure and flow range. Many times the turbine types are characterized but their effective "head range". Table 3.2 shows generally accepted values by turbine type. From table it is clear that for head between 2-40 m Kaplan turbine is used. As the head decreased the efficiency of turbine also decreases.
Table 3.2.Turbine selection
Turbine Style Head Range H (m)
Head Range H (ft) Kaplan and Propeller 2 < H < 40 6 < H < 125
Francis 10 < H <350 30 < H < 375 Pelton 50 < H < 1300 150 < H < 5000 Banki - Michell 3 < H < 250 9 < H < 750
Turgo 50 < H < 250 50 < H < 750
Another useful tool is the graph above. The figure 3.1 also includes flow information, so the turbine selection is more refined. The vertical axis units are for Head in Meters, and the horizontal axis for flow in cubic meters per second [9].
3.3 Turbine Model Testing
Before building large-scale installations, the design should be checked out with turbine model tests, using geometrically similar models of small and intermediate size, all operating at the same specific speed. Allowances must be made for the effects of friction, determined by the Reynolds number (density × rotational speed × runner diameter squared/viscosity) and for possible changes in scaled roughness and clearance dimensions. Friction effects are less important for large units, which tend to be more efficient than smaller ones [9].
Figure 3.1.Normal Range of operation by turbines