• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Researching water turbine designs.

Extracts from this document...

Introduction

Investigation: Design of a Runner

Background:

Runner – Is a rotating part of Turbine consisting of curved vanes/blades or buckets on wheel that is turned by pressure of high veloctiy of water, thereby transforming falling water energy into rotating mechanical energy.

There are mainly 3 types of Runners:

1) Kaplan Runner: They are quite suitable for low heads and large discharge/ head variations ranging from 10M to 60M.

2) Francis Runner: Have widest range of application. They can operate under very different head ranging from 30M to 700M.

3) Pelton Runner: They can operate under a very large range of heads up to 1800M.

Aim: To Define Type of Runner to be used in Hydro Power Plant in order to generate Power based on the net head of water and flow rate.

Research question: How does the Water head and flow rate effect the type and size of Runner.

Introduction:

Types of turbines:

Impulse turbines

Pelton turbines

Pelton turbines are impulse turbines where one or more jets impinge on a wheel carrying on its periphery a large number of buckets. Each jet issues water through a nozzle with a needle valve to control the flow. They are only used for high heads from 60 m to more than 1 000 m. The axes of the nozzles are in the plan of the runner. In case of an emergency stop of the turbine (e.g. in case of load rejection)

...read more.

Middle

The double regulation allows, at any time, for the adaptation of the runner and guide vanes coupling to any head or discharge variation. It is the most flexible Kaplan turbine that can work between 15% and 100% of the maximum design discharge. Single regulated Kaplan allows a good adaptation to varying available flow but is less flexible in the case of important head variation. They can work between 30% and 100% of the maximum design discharge.

 The flow enters in a radial manner inward and makes a right angle turn before entering the runner in an axial direction. The control system is designed so that the variation in blade angle is coupled with the guide-vanes setting in order to obtain the best efficiency over a wide range of flows and heads. The blades can rotate with the turbine in operation, through links connected to a vertical rod sliding inside the hollow turbine axis.

Bulb units are derived from Kaplan turbines, with the generator contained in a waterproofed bulb submerged in the flow.

Kaplan turbines are certainly the machines that allow the most number of possible configurations. The selection is particularly critical in low-head schemes where, in order to be profitable, large discharges must be handled. When contemplating schemes with a head between 2 and 5 m, and a discharge between 10 and 100 m3/sec, runners with 1.6 - 3.2 metres diameter are required, coupled through a speed increaser to a generator.

...read more.

Conclusion

It should be noted that it is difficult to measure the height at the discharge, so measure it say 300mm to 600mm back from the weir.

Cross Section Flow Method

For larger creeks, this method involves the cross sectional area of the flow and the speed of the flow. If you wish to ascertain the flow rate of a stream, when the 10 litre bucket method cannot be employed, you can get a rough idea by measuring the size (cross section) and average flow rate of the stream.

For this method the speed of the mid-stream surface water is measured by timing a float. Choose a part of the stream where the cross section is regular. Measure the cross section by finding the average depth as shown, and the width. Time the float over a short distance to obtain the speed.

The average speed of the whole stream can then be calculated by multiplying the measured speed by:

0.8 for a concrete channel

0.7 for an earth channel

0.5 for a rough hill stream

For streams less than 150 mm average depth, the factor becomes unpredictable and can be as low as 0.25. The flow rate is then equal to the distance that the float travelled multiplied by the correction factor and multiplied by the average depth and width of the stream and then divided by the number of seconds for the float to cover that distance.

If the measurements are taken in metres and the float is timed in seconds, then the result multiplied by 1000 will give you the litres per second flow rate. Overall accuracy of this method is about 80%.

...read more.

This student written piece of work is one of many that can be found in our International Baccalaureate Physics section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related International Baccalaureate Physics essays

  1. Suspension Bridges. this extended essay is an investigation to study the variation in tension ...

    the tension experienced is highest at a point which is approximately the mid-point of the distance between the two rigid supports (nails). From that point onwards, the tension starts decreasing. The minimum tension experienced will be at a point of application of force which is the farthest from the first rigid support.

  2. How does the mass of a spherical object and the height from which it ...

    When is changed but m is held constant changes proportionally, and when m is changed but is held constant also changes proportionally. This confirms this relationship, to be true. The error was .1 cm when dropping each object from the specified height, leading to corresponding errors in the graphs of mass vs.

  1. How does the number of holes in a plastic cup affect the time it ...

    when the number of holes at the bottom of the cup is 1 (27.93s + 28.60s + 26.69s + 26.62s + 27.31s) / 5 = 27.43 seconds Uncertainty for when the cup has one hole (28.60s-26.62s)/ 2 = .99 s Graph: Conclusion and Evaluation Conclusion: Based on the data collected,

  2. Incandescent 100 watt light bulb ban: A bright Idea ?

    Compact Fluorescent Lamps (CFLs) are a more modern type of fluorescent bulbs. They work in smaller packages hence the name compact. Like the regular fluorescent bulbs, they produce little heat and are very efficient. Low-pressure sodium lamps have the highest efficiency amongst all available light bulbs for outside (Steve)

  1. What would be the best geo-science solution to stop global warming?

    If the areas don't turn into a forest with wild life, they are basically tree farms. Another way to have less CO2 in the atmosphere is to not produce any CO2 anymore. This would mean that we not be allowed to burn any fossil fuels, instead we would use solar energy.

  2. World Energy resources

    Brief Procedure: Nuclear fission ----- Heat water to make steam ----- Steam turn turbines ----- Turbines turn generator ----- Electrical power Energy transfer during the procedure: nuclear energy --- kinetic energy of particles - thermal energy - kinetic energy of rotation --- electrical energy Advantages Disadvantages High power output Radioactive

  1. Physics Design - Leaky Bucket

    Fasten three metre rulers from the edge of the stool to the end of the trough, exactly parallel to each other. Place a large sheet of tissue-like paper on top of the rulers, so it is easy to read where the water has fallen.

  2. How does the sinkage depth of a tyre affect its rolling resistance ?

    The main of this experiment was to establish a relationship between sinkage depth of the tire and the rolling resistance it faces . The experiment involved allowing a bicycle , with specific air pressure which was measured using an air pressure gauge , with trainers to roll down a wooden

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work