Post on 15-Oct-2014
KATHMANDU UNIVERSITYSCHOOL OF ENGINEERING
DEPARTMENT OF MECHANICAL ENGINEERING
A Proposal on“Performance Testing of Micro Hydro & Laboratory Setup”
as the Fourth Year Undergraduate Project Works
Supervisor:Mr. Biraj Singh Thapa
Submitted by:Abinash Baral (41053)
Rojan K. Katuwal (41089)
28 December 2011
ABSTRACT
This is the proposal submitted to Department of Mechanical Engineering in the project
entitled “Performance Testing of Micro Hydro & Laboratory Setup”. The primary target
of our project is to setup a laboratory for the testing of micro-hydro cross-flow turbines. The
initial phase will include the dismantling of the previous test rig placed at pico-hydro turbine
testing laboratory at Kathmandu University (KU) and re-installing it at the newly built
turbine testing laboratory at KU. After, initial performance tests the latter stages will include
modifications and improvements in the test rigs for other micro-hydro turbine testing.
This project intends to study testing procedures adopted elsewhere and every possibility of
implementation. The success of our project might ease and establish certain procedures of
turbine testing, further relieving the pressure on micro hydro-power developers. Our aim is to
study and test micro-hydro turbines and prepare hill charts of the turbine with a proper
laboratory setup.
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TABLE OF CONTENTS
Abstract ii
Chapter 1: Introduction 1
1.1 Rationale 11.2 Objectives
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Chapter 2: Literature Review 2
Chapter 3: Methodology 5
Chapter 4: Discussion 7
4.1 Laboratory test 7
Chapter 5: Gantt Chart 9
Chapter 6: Conclusion 10
References 11
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CHAPTER 1
INTRODUCTION
1.1 Rationale
The easy availability as well as the abundance of falling water sources is the main inspiration
for the project. Besides the environment friendly nature of micro-hydro powers, easy
production is equally relevant in economy stripped country like ours. If simple procedures of
turbine testing are used then optimization of the turbines will be easier. This is a good
possibility of its wide acceptance among people that may even lead to establishments of
micro-hydro systems at different parts of the country electrifying the rural and semi-urban
communities.
1.2 Objectives
The main objectives of our project include:
i. To test the efficiency of the 15 KW cross-flow turbine currently installed in the rig.
ii. To prepare hill chart of the same.
iii. To further test other micro-hydro turbines and prepare their hill charts.
The secondary objectives of our project include:
i. To study other testing laboratory setup.
ii. To apply testing procedure considering availability and accuracy.
iii. To test micro-hydro turbines.
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CHAPTER 2
LITERATURE REVIEW
Micro hydro is hydro power with electrical output of five to 20 kilowatts. Hydro power systems
of this size benefit in terms of cost and simplicity from different approaches in the design,
planning and installation than those which are applied to larger hydro power. Recent innovations
in micro hydro technology have made it an economic source of power even in some of the
world’s poorest and most inaccessible places. It is also a versatile power source. AC electricity
can be produced enabling standard electrical appliances to be used and the electricity can be
distributed to a whole village. Common examples of devices which can be powered by micro-
hydro are light bulbs, radios, televisions, refrigerators and food processors.
The purpose of a hydraulic turbine is to transform the water potential and kinetic energy to
mechanical rotational energy. Various types of turbines exist to cope with different levels of
head and flow. The two broad categories are:
Impulse turbines – notably the Pelton, Turgo or the Banki-Michell (cross-flow) - in which
water impinges or enters the runner, which is designed to change the water’s direction
and thereby extract the momentum from it with scarce change of pressure energy.
Reaction turbines – notably Francis and Kaplan – which run full of water and in effect,
generate hydrodynamic “lift” forces to propel the runner blades, extracting thus the
pressure energy of inflowing water.
Crossflow turbines are widely used on micro hydro sites with typical power outputs from 5 kW
up to 100 kW, though they can actually be up to 3 MW in size on the very largest systems,
though generally speaking there are better turbine choices for these higher power outputs. They
will work on net heads from just 1.75 metres to 200 metres, though there are more appropriate
turbine choices for sites with heads above 40 metres. They will work on average annual flows as
low as 40 litres/second or up to 5 m3/s, though on the higher flow rates there may be better other
turbine types to consider.
A cross-flow turbine gets its name from the way the water flows through, or more correctly
‘across’ the rotor as shown in figure below. The water flows over and under the inlet guide-vane
which directs flow to ensure that the water hits the rotor at the correct angle for maximum
efficiency. The water then flows over the upper rotor blades, producing a torque on the rotor,
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then through the centre of the rotor and back across the low rotor blades producing more torque
on the rotor. Most of the power is extracted by the upper blades (roughly 75%) and the
remaining 25% by the lower blades. Obviously the rotor is rotating, so what are the upper blades
one moment will be the lower blades the next.
Figure – Crossflow turbine in cross-section.
One of the advantages of a crossflow turbine is debris tolerance; leaves etc. that could get pushed
into and stuck on the upper blades are washed off by the exiting water on the lower blades, hence
the rotor is self cleaning. Also the centrifugal force tends to throw trapped debris outwards,
further increasing the self-cleaning capabilities.
Crossflow turbines are an impulse turbine, which means that the rotor is spinning in air and is not
fully-flooded like in a reaction turbine. The water exits the rotor and falls into the draft tube,
which can be many metres long (though not normally more than 1/3 of the total net head across
the system). The exiting water fills the draft tube from just below the rotor to the discharge
water level. A negative pressure inside the turbine cavity i.e. ‘suction head’ is created with the
air inlet valve on the front turbine casing. The positive water pressure from the upstream side of
the rotor is called the ‘pressure head’ and the sum of the pressure and suction heads equals the
net head across the hydro system.
The advantage of using a draft tube to maximise the suction head is that the long draft tube
moves the main body of the crossflow turbine upwards, away from the discharge water level and
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(hopefully) above the floodwater levels during high flow events. If the main body of the turbine
was still likely to get flooded during high flow events it would have to be built into a ‘tanked’
enclosure. Another major advantage of a crossflow turbine is there wide operating flow range
with a high efficiency across the whole range.
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CHAPTER 3
METHODOLOGY
Fig: Methodology
Firstly, we will survey the present situation and test facilities at the Laboratory at KU. .
After that we will study the prevailing testing procedures and laboratory setup.
Then, the laboratory will be redesigned.
After that, tests will be carried out on the laboratory followed by series of modifications
and corresponding tests.
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LABORATORY SETUP STUDY
LAB OPTIMIZATION
TESTING
PROJECT SELECTION
LITERATURE SURVEY
MICRO-HYDRO STUDY
From Source
To other test rigs
Pressure Tank
Reservoir tank Pump
Turbine Re-collection
Tank
Pressure Regulating
Tank
CHAPTER 4
DISCUSSION
4.1 Laboratory
Fig: Diagrammatic representation of the current testing lab
The testing lab is as shown above. Water from source is collected in the reservoir tank which is
connected to the pressure tank with a valve. The pressure tank is connected to the water
transmission pipes and pressure regulating tank. The pressure regulating tank has a valve for
controlling the water flow to the tank itself which helps to maintain the desired pressure/head
and is connected to the reservoir tank. The turbine setup is connected to the transmission pipes
and the water outflow from the turbine is collected in the re-collection tank which is connected to
the reservoir tank. Thus, once the water in the reservoir tank reaches to the desired level tests are
performed without the loss of water unless there are leakages.
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The turbines in the field should be supplied with natural flow of water (Q) under some head (H).
However, in the laboratory the flow and head is obtained by a suitable pumping unit which
supplies water under a specified pressure. First, the pump is started and the inlet and other valves
are opened to ensure supply of water to the turbine. After the setup, the rpm of the propeller shaft
and the output of the alternator are measured using tachometer, multimeter and loads of varying
power ratings. These data are then used to calculate the efficiency and power output of the
turbine.
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CHAPTER 5
GANTT CHART
S. No.
Activities Sept Oct Nov Dec Jan Feb Mar Apr May Jun Jul
1Project Selection
2Literature Review
3Laboratory Setup Study
4Optimization of Laboratory
5Actual Testing of Turbines
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CHAPTER 6
CONCLUSION
Mirco-hydro systems are of great significance in rural Nepal because of its difficult topography
and absence of transmission lines. They can be solutions to electrifying rural households. Small
communities can be greatly served in the current times where urban areas are facing large-
spanned loadshedding. After the completion of the project we intend to obtain a fully equipped
laboratory with testing facilities for cross-flow turbines of varying range giving reliable, accurate
and simple to obtain results. We also hope for developing the skills and knowledge of various
engineering procedure for the successful accomplishment of the given job.
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REFERENCES
Khurmi R.S. (1970). The textbook of hydraulics, fluid mechanics and hydraulic machines. S. Chand & Company Ltd.: New Delhi, India.
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