lab 8 full report.docx

8/10/2019 Lab 8 Full report.docx

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EML 331/2 Engineering Laboratory II

Experiment 8Hydraulic Turbines

PART 1

Title : Performance Test on Francis Turbine (Reaction)

Objective1. To carry out the performance test on Francis Turbine

2. Draw the inlet and exit velocity diagrams

3. Calculate specific work, shaft power, hydraulic power output, overall efficiency,degree of reaction at various speeds and blade positions

Introduction

Turbines are energy producing devices as they extract energy from the fluid and transfermost of that energy to some form of mechanical energy output, typically in the form of a

rotating shaft. The fluid at the outlet of a turbine suffers an energy loss, typically in the

form of a loss of pressure. The purpose of a turbine is to extract energy from a fluid,resulting in a decrease of fluid pressure, not necessarily a decrease of fluid speed across

the turbine.

The Francis turbine is a type of water turbine that was developed by James B. Francis inLowell, Massachusetts. It is an inward-flow reaction turbine that combines radial and

axial flow concepts. Francis turbine is considered as a reaction turbine which consists of

fixed guide vanes called stay vanes, adjustable guide vanes called wicket gates, androtating blades called runner blades. Flows enter tangentially at high pressure is turned

toward the runner by the stay vanes as it moves along the spiral casing or volute, and then

passes through the wicket gates with a large tangential velocity component.

Francis turbine is somewhat similar in geometry to a centrifugal or mixed-flow pump, but

with the flow in the opposite direction. However the typical pump running backward

would not be a very efficient turbine. Reaction turbine can be classified according to theangle that the flow enters the runner. If the flow enters the runner radially, the turbine is

called as Francis radial-flow turbine and if the flow enters the runner at some angle

between radial and axial, the turbine is called Francis mixed-flow turbine. Francisturbine is used only when there is a band on the runner by some of the hydroturbine

engineers.

TheoryHydraulic turbines are components of a hydraulic power station. They are designed to

convert the potential energy of power contained in rivers, canals into mechanical energy

which is then converted into electrical energy by electrical generators. They are of two

types of turbine which are Impulse turbine and Reaction turbine.

The static pressure (1.1) at runner inlet is greater than at outlet (1.2). The conversion of

potential energy into kinetic energy is distributed over the blading system (2) andrunner.in Francis turbine part of the pressure energy is converted into velocity in blade


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system (1) and accelerated flow enters runner (2) and from outside and flow radially

through inside. The peripherial velocities at inlet and exit are different. The moving

blades are curved backwards. Water exits axially from runner at 3. The flow rate andhence the power can be regulated by adjustable fixed blades.

Figure 1 Figure 2

Figure 3: Blades were closed and generates zero power

Figure 4: Blades are opened widely and generates full power

Relevant Formula

The index 0 refers to plane upstream of fixed blade T to plane between the fixed and

moving blades and index 2 to the plane at outlet downstream of moving blades.

The peripheral velocities and are obtained from required speed and the outsideand inside diameters and .


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The radial component of absolute inlet velocity can be calculated from the water flowrate through the annular space upstream of the wheel.

By knowing the inlet blade angle, of the moving blade relative velocity at inlet is givenby

The inlet absolute velocity component in the peripheral direction is important tocalculate the power given by

The flow inlet angle, through the fixed blades is determined by


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The radial component of absolute inlet velocity , and exitabsolute velocity component in the peripherial direction are calculated similar to ,and .

The specific blade work is given by

The turbine power is obtained by knowing the mass flow rate of water and specific blade

work.

The effective power is calculated by

The hydraulic input and overall efficiency

The degree of reaction is obtained from inlet velocity and head.


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where Formula of Mechanical Power and Hydraulic Power,

ApparatusA fully functional laboratory model Francis turbine with adjustable fixed blades, runner

blades and measuring devices for brake power, speed, torque, flow rate and pressure

Result

Blade

Position

Pressure (Bar) Volume

Flow Rate,

V (l/min)

Volume

Flow Rate,

V (m3/s)

Torque,

T (Nm)

Effective

Power, Peff

(W)

Wheel

Speed, N

(rpm)

Mass Flow

Rate, m

(kg/s)

Head,

H

(m)P1 P2 P3

0 1.637 1.570 1.063 47.0 0.000783 0.61 0.4941 1800 0.783 6.361

1 1.634 1.558 1.062 56.5 0.000942 0.61 0.4941 1962 0.942 6.330

2 1.627 1.541 1.062 68.4 0.001140 0.61 0.4941 1965 1.140 6.259

3 1.620 1.520 1.061 80.4 0.001340 0.61 0.4941 1910 1.340 6.188

4 1.612 1.501 1.060 96.7 0.001612 0.61 0.4941 1902 1.612 6.106

5 1.600 1.464 1.058 105.4 0.001757 0.61 0.4941 1744 1.757 5.984

6 1.590 1.445 1.058 115.1 0.001918 0.61 0.4941 1612 1.918 5.882

7 1.579 1.415 1.057 124.8 0.002080 0.61 0.4941 1486 2.080 5.770

8 1.570 1.393 1.057 133.3 0.002222 0.61 0.4941 1377 2.222 5.6789 1.562 1.371 1.056 140.2 0.002337 0.61 0.4941 1280 2.337 5.596

10 1.552 1.345 1.055 147.6 0.002460 0.61 0.4941 1164 2.460 5.494

Table 1.1: Recorded Data of Francis Turbine at 1,800 rpm

Data Available

Turbine Speed, N 1800 rpm

Atmospheric Pressure, Po 1.013 bar

Outside Runner Diameter, D1 0.08 m

Inside Runner Diameter, D2 0.04 m

Blade Width, b1 0.01 m

Blade Thickness Projection, t 0.0025 m

Number of Runner Blades, z 11

Inlet Angle of Runner Blade, 1 165 degree 2.8798 radian

Outlet Angle of Runner Blades, 2 50 degree 0.8727 radian

Blade Efficiency, b 0.9

Mechanical Efficiency, m 0.9

Density of Water, w 1000 kg/m3

Table 1.2: Data Available for Francis Turbine Calculation at 1,800rpm


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Blade

Position

Peripheral

Velocities (m/s) Radial Component of

Inlet Velocity, C1r(m/s)

Inlet Relative

Velocity, W1

(m/s)

Inlet Absolute

Velocity Component,

C1u(m/s)

Flow Inlet

Angle, 1

U1 U2 Radian Degree

0 7.540 3.770 0.3500 1.352 8.846 2.266 129.8

1 8.218 4.109 0.4207 1.626 9.789 2.461 141.0

2 8.231 4.115 0.5093 1.968 10.132 2.878 164.9

3 8.001 4.000 0.5987 2.313 10.235 3.348 191.8

4 7.967 3.984 0.7200 2.782 10.654 3.866 221.5

5 7.305 3.653 0.7848 3.032 10.234 4.385 251.3

6 6.752 3.376 0.8571 3.311 9.951 4.923 282.0

7 6.225 3.112 0.9293 3.590 9.693 5.476 313.8

8 5.768 2.884 0.9926 3.835 9.472 5.982 342.7

9 5.362 2.681 1.0440 4.034 9.258 6.434 368.6

10 4.876 2.438 1.0991 4.246 8.978 6.980 399.9

Table 1.3: Peripheral Velocities, Inlet Velocity and Flow Inlet Angle of Various Blade Positions at1,800 rpm

Blade

Position

Radial Component

of Exit Velocity, C2r(m/s)

Exit Relative

Velocity, W2

(m/s)

Exit Absolute

Velocity

Component, C2u

(m/s)

Specific

Blade Work,

Es (J/kg)

Turbine

Power, P

(W)

Effective

Power, Peff

(W)

0 0.7980 1.0417 3.100 55.01 43.09 34.901 0.9593 1.2523 3.304 66.87 62.97 51.00

2 1.1613 1.5160 3.141 70.47 80.33 65.07

3 1.3651 1.7820 2.855 70.46 94.42 76.48

4 1.6418 2.1432 2.606 74.50 120.07 97.26

5 1.7895 2.3361 2.151 66.91 117.53 95.20

6 1.9542 2.5511 1.736 61.33 117.65 95.30

7 2.1189 2.7660 1.334 56018 116.85 94.65

8 2.2632 2.9544 0.985 51.80 115.07 93.21

9 2.3804 3.1074 0.683 47.80 111.70 90.48

10 2.5060 3.2714 0.335 42.96 105.67 85.59

Table 1.4: Exit Velocity, Specific Blade Work, Turbine Power and Effective Power of Various Blade

Position at 1,800 rpm


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Blade

Position

Hydraulic

Power, Phyd

(W)

Overall

Efficiency, o(%)

Degree

of

Reaction

Hydraulic

Power, Phyd(W)

Mechanical

Power, Pmech(W)

Efficiency,

(%)

0 48.88 71.41 0.3720 81.14 114.98 141.71

1 58.48 87.22 0.2271 97.07 125.33 129.11

2 70.00 92.96 0.1620 116.19 125.52 108.033 8134 94.03 0.1342 135.02 122.01 90.36

4 96.54 100.75 0.0481 160.25 121.50 75.82

5 103.12 92.32 0.1026 171.17 111.41 65.08

6 110.69 86.10 0.1356 183.74 102.97 56.04

7 117.73 80.40 0.1624 195.43 94.92 48.57

8 123.75 75.32 0.1857 205.42 87.96 42.82

9 128.28 70.53 0.2095 212.95 81.77 38.40

10 132.59 64.55 0.2412 220.11 74.36 33.78

Table 1.5: Hydraulic Power, Overall Efficiency, Degree of Reaction, Mechanical Power and

Efficiency of Various Blade Position at 1,800 rpm

Blade

Position

Pressure (Bar) VolumeFlow Rate,

V (l/min)

VolumeFlow Rate,

V (m3/s)

Torque,

T (Nm)

EffectivePower, Peff

(W)

WheelSpeed, N

(rpm)

Mass FlowRate, m

(kg/s)

Head,H

(m)P1 P2 P3

0 1.958 1.880 1.062 58.6 0.000977 0.61 0.4941 2200 0.977 9.633

1 1.950 1.862 1.062 70.9 0.001182 0.61 0.4941 2503 1.182 9.551

2 1.942 1.838 1.061 85.0 0.001417 0.61 0.4941 2513 1.417 9.470

3 1.927 1.796 1.059 104.9 0.001748 0.61 0.4941 2515 1.748 9.317

4 1.918 1.764 1.057 120.2 0.002003 0.61 0.4941 2384 2.003 9.225

5 1.901 1.723 1.057 131.5 0.002192 0.61 0.4941 2180 2.192 9.052

6 1.885 1.684 1.057 145.3 0.002422 0.61 0.4941 2021 2.422 8.889

7 1.870 1.647 1.055 156.4 0.002607 0.61 0.4941 1880 2.607 8.736

8 1.855 1.607 1.055 166.2 0.002770 0.61 0.4941 1763 2.770 8.583

9 1.841 1.574 1.054 175.5 0.002925 0.61 0.4941 1623 2.925 8.44010 1.824 1.540 1.053 185.0 0.003083 0.61 0.4941 1488 3.083 8.267

Table 1.6: Recorded Data of Francis Turbine at 2,200 rpm

Data Available

Turbine Speed, N 2200 rpm












Table 1.7: Data Available for Francis Turbine Calculation at 2,200rpm


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Blade

Position

Peripheral

Velocities

(m/s)Radial Component of


Inlet Relative

Velocity, W1

(m/s)

Inlet Absolute

Velocity

Component, C1u(m/s)

Flow Inlet

Angle, 1

U1 U2 Radian Degree

0 7.540 3.770 0.3500 1.352 8.846 2.266 129.8

1 8.218 4.109 0.4207 1.626 9.789 2.461 141.0

2 8.231 4.115 0.5093 1.968 10.132 2.878 164.9

3 8.001 4.000 0.5987 2.313 10.235 3.348 191.8

4 7.967 3.984 0.7200 2.782 10.654 3.866 221.5

5 7.305 3.653 0.7848 3.032 10.234 4.385 251.3

6 6.752 3.376 0.8571 3.311 9.951 4.923 282.0

7 6.225 3.112 0.9293 3.590 9.693 5.476 313.8

8 5.768 2.884 0.9926 3.835 9.472 5.982 342.7

9 5.362 2.681 1.0440 4.034 9.258 6.434 368.6

10 4.876 2.438 1.0991 4.246 8.978 6.980 399.9Table 1.8: Peripheral Velocities, Inlet Velocity and Flow Inlet Angle of Various Blade Positions at

2,200 rpm

Blade

Position

Radial Component


Exit Relative

Velocity, W2

(m/s)

Exit Absolute

Velocity Component,

C2u(m/s)

Specific

Blade Work,

Es (J/kg)

Turbine

Power, P

(W)

Effective

Power, Peff

(W)

0 0.9949 1.2988 3.773 82.55 80.62 65.30

1 1.2038 1.5714 4.232 108.40 128.09 103.75

2 1.4432 1.8839 4.052 114.34 161.99 131.21

3 1.7810 2.3250 3.773 121.82 212.98 172.51

4 2.0408 2.6641 3.281 116.70 233.79 189.37

5 2.2327 2.9145 2.692 104.46 228.95 185.45

6 2.4670 3.2204 2.163 96.69 234.16 189.67

7 2.6554 3.4664 1.709 89.51 233.33 188.99

8 2.8218 3.6836 1.325 83.75 231.99 187.92

9 2.9797 3.8897 0.899 76.32 223.23 180.82

10 3.1410 4.1003 0.481 69.39 213.97 173.31

Table 1.9: Exit Velocity, Specific Blade Work, Turbine Power and Effective Power of Various Blade

Position at 2,200 rpm


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Blade

Position

Hydraulic

Power, Phyd

(W)

Overall

Efficiency, o(%)

Degree of

Reaction

Hydraulic

Power, Phyd(W)

Mechanical

Power, Pmech(W)

Efficiency,

(%)

0 92.30 70.75 0.3768 153.21 140.53 91.73

1 110.72 93.70 0.1707 183.80 159.89 86.99

2 131.61 99.70 0.1038 218047 160.53 73.483 159.80 107.96 0.0071 265.26 160.66 60.56

4 181.30 104.45 0.0144 300.96 152.29 50.60

5 194.62 95.29 0.0741 323.07 139.26 43.10

6 211.17 89.82 0.0969 350.54 129.10 36.83

7 223.39 84.60 0.1207 370.83 120.09 32.38

8 233.23 80.57 1.1353 387.17 115.62 29.09

9 242.19 74.66 0.1665 402.04 103.68 25.79

10 250.06 69.31 0.1907 415.10 95.05 22.90


Efficiency of Various Blade Position at 2,200 rpm

Pressure (Bar) Volume

Flow Rate,

V (l/min)

Volume

Flow Rate,

V (m3/s)

Torque,

T (Nm)

Effective

Power, Peff

(W)

Wheel

Speed, N

(rpm)

Mass Flow

Rate, m

(kg/s)

Head,

H (m)P1 P2 P3

2.292 1.938 1.048 209.7 0.003495 0.61 0.4941 2200 3.495 13.038

2.090 1.783 1.053 191.1 0.003185 0.61 0.4941 2000 3.185 10.979

1.900 1.642 1.053 171.9 0.002865 0.61 0.4941 1800 2.865 9.042

1.733 1.516 1.055 153.7 0.002562 0.61 0.4941 1600 2.562 7.339

1.596 1.411 1.057 137.8 0.002297 0.61 0.4941 1400 2.297 5.943

1.470 1.316 1.057 120.6 0.002010 0.61 0.4941 1200 2.010 4.659

1.360 1.230 1.059 103.5 0.001725 0.61 0.4941 1000 1.725 3.537

1.307 1.182 1.059 102.3 0.001705 0.64 0.5184 800 1.705 2.997

Table 1.11: Recorded Data of Francis Turbine at Fixed Blade Position #8

Data Available

Blade Position 8












Table 1.12: Data Available for Francis Turbine Calculation at Fixed Blade Position #8


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Peripheral

Velocities (m/s) Radial Component of


Inlet Relative

Velocity, W1

(m/s)

Inlet Absolute

Velocity Component,

C1u(m/s)

Flow Inlet

Angle, 1

U1 U2Radia

n

Degre

e

9.215 4.608 1.5615 6.033 15.043 5.926 339.5

8.378 4.189 1.4230 5.498 13.688 5.935 340.0

7.540 3.770 1.2800 4.946 12.317 5.933 339.9

6.702 3.351 1.1445 4.422 10.973 5.954 341.2

5.864 2.932 1.0261 3.965 9.694 6.042 346.2

5.027 2.513 0.8980 3.470 8.378 6.118 350.5

4.189 2.094 0.7707 2.978 7.065 6.225 356.7

3.351 1.676 0.7617 2.943 6.194 7.011 401.7

Table 1.13: Peripheral Velocities, Inlet Velocity and Flow Inlet Angle of Various Blade Positions at

Fixed Blade Position #8

Radial Component


Exit Relative

Velocity, W2

(m/s)

Exit AbsoluteVelocity

Component, C2u

(m/s)

Specific

Blade Work,

Es (J/kg)

Turbine

Power, P

(W)

Effective

Power, Peff

(W)

3.5604 4.6477 1.620 131.16 458.40 371.31

3.2446 4.2355 1.466 108.53 345.67 280.00

2.9186 3.8100 1.321 87.89 251.80 203.96

2.6096 3.4066 1.161 69.65 178.43 144.53

2.3396 3.0542 0.969 54.01 124.03 100.47

2.0476 2.6730 0.795 40.11 80.63 65.31

1.7573 2.2940 0.620 28.30 48.81 39.54

1.7369 2.2674 0.218 20.39 34.77 28.16

Table 1.14: Exit Velocity, Specific Blade Work, Turbine Power and Effective Power of Various BladePosition at Fixed Blade Position #8

Hydraulic

Power, Phyd

(W)

Overall

Efficiency, o(%)

Degree of

Reaction

Hydraulic

Power, Phyd(W)

Mechanical

Power, Pmech(W)

Efficiency,

(%)

447.01 83.06% 0.1058 742.04 140.53 18.94%

343.02 81.63% 0.1207 569.42 127.76 22.44%

254.13 80.26% 0.1356 421.85 114.98 27.26%

184.44 78.36% 0.1547 306.17 102.21 33.38%133.90 75.03% 0.1851 222.27 89.43 40.24%

91.86 71.10% 0.2232 152.48 76.65 50.27%

59.86 66.05% 0.2722 99.36 63.88 64.29%

50.13 56.18% 0.3377 83.21 53.62 64.43%


Efficiency of Various Blade Position at Fixed Blade Position #8


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Sample Calculation

For Blade position 0

[ ]


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[ ]


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( )


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Discussion

Refer to the graph 1, the effective power and mechanical power of the Francis turbine

against fixed blade at 1800 rpm and 2200 rpm have been shown. The trend of all the

graph lines are increasing until a certain value and then decreasing to a point. The

effective powers for both cases are lower than the mechanical powers of the turbine. This

is due to the calculation of mechanical power is not including the volume flow rate andthe blade efficiency and mechanical efficiency. The volume flow rate of water coming

out from the turbine after loss of energy is deducted from mechanical power is calculated,

the value getting is the effective power.

Refer to graph 2, the efficiency and overall efficiency of Francis turbine at 1800 rpm and

2200 rpm have been shown. The overall efficiency at 1800 rpm and 2200 rpm increase to

a certain value firstly and then decrease to a certain point while the efficiency at 1800

rpm and 2200 rpm show a decreasing trend. This is due to the blade position problem as

the blade opening is bigger, then water pressure will dop and this has cause the speed of

turbine runner decrease. The overall efficiency of turbine is calculated based on effectivepower while the efficiency of turbine is calculated based on the mechanical power. Thus,

the efficiency and overall efficiency of Francis turbine decrease when the blade position

increases.

Refer to graph 3, the efficiency and overall efficiency of Francis turbine against the

degree of reaction of the turbine have been shown. Degree of reaction or reaction ratio (R)

is defined as the ratio of static pressure drop in the rotor to the static pressure drop in the

stage or as the ratio of static enthalpy drop in the rotor to the static enthalpy drop in the

stage. Degree of reaction (R) is an important factor in designing the blades of a turbine,

compressors, pumps and other turbo-machinery. It also tells about the efficiency of

machine and is used proper selection of machine for the required purpose. The efficiency

and overall efficiency decrease with the increasing of degree of reaction at 1800 rpm and

2200 rpm. This is due to the increasing pressure in rotor blade and cause the pressure at

the stator blade to be decreased. The rotor blade has large distribution of the total work

and thus, the degree of reaction increased.

The efficiency increased with the increasing of the degree of reaction while the overall

efficiency decreased with the increasing of the degree of reaction when the blade position

is fixed at number 8 with the different turbine speed. The static enthalpy decreases as the

stator blade is fixed at position 8. Thus, the pressure to turn the turbine decrease as the

turbine speed decrease. The hydraulic power will be decreased too when the turbine

speed decreased. This will cause the efficiency increased and as the degree of reaction

increased. When the speed of turbine decreased, the rotor blade will turn slower and the

volumetric flow rate increased. The effective power and hydraulic power of the turbine

decreased and hence the overall efficiency decreased.


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Refer to graph 5, the efficiency and overall efficiency of the turbine against speed at the

fixed of position 8 have been shown. The effective power and mechanical power of the

turbine increased with the increasing of the speed of turbine. The effective power is

28.16W at 800 rpm has been increased to 371.31W at 2200 rpm. While the mechanical

power is 53.62W at 800 rpm has been increased to 140.53W at 2200 rpm. This has shown

that when increasing of the speed of turbine will turns the rotor blade faster and hence thepower generated will be increased too.

Errors and Precautions

There are some errors occur during this experiment. Firstly, the reading from un-

calibrated electronic sensor change rapidly which has a hard time taking which an exact

reading, so we can only take the random readings that suitable. Next, the water that used

is not pure, which there are impurities in water, so the density is not same as pure water

as in theory. There are some leakages along the pipe. This will affect the reading values.

Besides that, the water bubbles exist throughout the pipe can cause the cavitation effect in

the turbine and this will reduce the head and local static pressure drop to the vapour

pressure level. The noise and vibration of the turbine will be produced because of the

cavitation effect. This will reduce the accuracy of the experiment. The vibration of the

pipe due to motor, pump and water flow will affect the accuracy of the result. Lastly,

there is minor loss due to friction inside the pipe.

There are some precautions needed in this experiment in order to reduce the errors.

Firstly, for accurate readings, make sure to take the readings after 3 minutes for the fluid

in stable condition. The readings should be taken for a few times in order to get the

average value. The electronic sensor used can be hooked up to a closed loop system that

feedback the result by adjusting the sampling rate of each parameter. Next, make sure thewater that being used is pure water. Make sure there are no leakages along the pipe.

Besides, a closed piping system should be installed where the output of the water directly

flow into the hydraulic bench instead of letting water being drained off from the piping

system. A damper as a good vibration absorber should be installed in order to reduce

vibration of the turbine. Lastly, we need to consider the minor loss due to friction inside

the pipe

Conclusion

Throughout this experiment, we get to know about the Francis turbine more by changing

the fixed blade position at 1800 rpm and 2200 rpm and also changing the speeds at fixed

blade position of 8. The result obtained has been tabulated and graphs have been plotted

to show the characteristic and performance of the Francis turbine.


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PART 2

Title: Performance Test on Pelton Turbine (Impulse)

Objective:To determine the operating characteristics of Pelton Turbine at various speed.

Introduction

Fluid is sent through the nozzle so that most of its available mechanical energy is

converted into kinetic energy in an impulse turbine. The bucketshaped vane is impinged

by the high speed jet that transfers the energy to the turbine shaft. Lester A. Pelton has

invented the modern and most efficient type of impulse turbine in 1878 and the rotating

wheel is now called a Pelton wheel in his honor.

The buckets of a Pelton wheel are designed so as to split the flow in half and turn the

flow nearly 180 around (with respect to a frame of reference moving with the bucket).

The splitter ridge shape has been modelled by Pelton after the nostrils of a cows nose. A

portion of the outermost part of each bucket is cut out so that the majority of the jet can

pass through the bucket that is not aligned with jet (bucket n+1in Figure 5) to reach the

most aligned bucket (bucket n in Figure 5). In this way, the maximum amount of

momentum from the jet is utilized.

Figure 5: Schematic diagram of a Pelton-type impulse turbine; the turbine shaft is

turned when high speed fluid from one or more jets impinges on buckets mounted

to the turbine shaft.

Theory where


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where

Result

Drum Radius, r = 0.0261m

Water Head, h = 4m

Specific Weight of Water, = 9785 N/m3

Part (A) Frequency, f=40 Hz

No

Load (N)Torque,

T (Nm)

Wheel

Speed, N

(rpm)

Angular

Velocity,

()

Mechanical

Power, Pm

(W)W1 W2 W

1 11.7 26.5 14.8 0.386 1043 109.267 42.208

2 7.7 20.5 12.8 0.334 1140 119.429 39.899

3 12.3 26.2 13.9 0.363 1188 124.457 45.152

4 8.0 22.4 14.4 0.376 1252 131.162 49.296

5 7.4 21.7 14.3 0.373 1290 135.143 50.439

6 7.6 21.4 13.8 0.360 1318 138.076 49.732

7 7.1 18.9 11.8 0.308 1364 142.895 44.009

8 8.6 20.7 12.1 0.316 1385 145.095 45.823

9 6.9 18.5 11.6 0.303 1413 148.029 44.817

10 7.4 18.5 11.1 0.290 1438 150.648 43.644

Table 2.1: Load, Torque, Wheel Speed, Angular Velocity and Mechanical Power

at frequency=40 Hz


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No

Volume

Flow Rate,

Q (l/min)

Volume

Flow Rate, Q

(xm3/s)

Hydraulic

Power, Ph

(W)

Efficiency,

(%)

Hydraulic

Pressure,

Phyd(bar)

Mechanical

Pressure,

Pmech(bar)

1 22.3 3.72 54.551 77.4 0.9 2.4

2 21.9 3.65 53.573 74.5 1.0 2.4

3 21.2 3.53 51.861 87.1 1.1 2.4

4 20.8 3.47 50.882 96.9 1.2 2.4

5 20.4 3.40 49.904 101.1 1.3 2.4

6 20.3 3.38 49.659 100.1 1.4 2.5

7 19.8 3.30 48.436 90.9 1.5 2.5

8 19.2 3.20 46.968 97.6 1.6 2.5

9 18.9 3.15 46.234 96.9 1.7 2.5

10 18.6 3.10 45.500 95.9 1.8 2.5

Table 2.2: Volume Flow Rate, Hydraulic Power, Efficiency, Inlet and Outlet

Pressure at frequency=40 Hz

Part (B) Frequency, f=55 Hz

No

Weight of Load (N)Torque, T

(Nm)

Wheel

Speed, N

(rpm)

Angular

Velocity,

()

Mechanical

Power, Pm

(W)W1 W2 W

1 20.8 46.5 25.7 0.671 1388 145.410 97.536

2 15.2 37.8 22.6 0.590 1408 147.505 87.007

3 16.0 41.1 25.1 0.655 1508 157.981 103.495

4 18.0 44.5 26.5 0.692 1535 160.810 111.224

5 19.2 42.0 22.8 0.595 1593 166.886 99.310

6 21.4 44.8 23.4 0.611 1630 170.762 104.291

7 19.5 39.6 20.1 0.525 1702 178.305 93.5408 21.4 42.3 20.9 0.545 1745 182.810 99.721

9 21.0 43.8 22.8 0.595 1777 186.162 110.781

10 22.0 45.6 23.6 0.616 1792 187.733 115.636

Table 2.3: Load, Torque, Wheel Speed, Angular Velocity and Mechanical Power

at frequency=55 Hz


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No

Volume

Flow Rate,

Q (l/min)

Volume

Flow Rate, Q

(xm3/s)

Hydraulic

Power, Ph

(W)

Efficiency,

(%)

Hydraulic

Pressure,

Phyd(bar)

Mechanical

Pressure,

Pmech(bar)

1 53.2 8.87 130.141 74.9 1.5 4.2

2 52.7 8.78 128.917 67.5 1.6 4.2

3 51.9 8.65 126.960 81.5 1.7 4.2

4 51.3 8.55 125.493 88.6 1.8 4.2

5 50.5 8.42 123.536 80.4 1.9 4.2

6 50.1 8.35 122.557 85.1 2.0 4.2

7 49.7 8.28 121.579 76.9 2.1 4.2

8 49.3 8.22 120.600 82.7 2.2 4.2

9 48.9 8.15 119.622 92.6 2.3 4.2

10 48.8 8.13 119.377 96.9 2.4 4.2

Table 2.4: Volume Flow Rate, Hydraulic Power, Efficiency, Inlet and Outlet

Pressure at frequency=40 Hz


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Figure 2.1: Graph of Torque against Wheel Rotational Speed for f=40Hz

Figure 2.2: Graph of Volume Discharged Rate against Wheel Rotational Speed

for f=40Hz

2.00

2.20

2.40

2.60

2.80

3.00

3.20

3.40

3.60

3.80

4.00

1000 1050 1100 1150 1200 1250 1300 1350 1400 1450 1500

VolumeFlowRate,Q(x10^-4m^3/

s)

Wheel rotational Speed, (rpm)

Graph of Volume Flow Rate against Wheel Rotational Speed

(40 Hz)

0.280

0.300

0.320

0.340

0.360

0.380

0.400

1000 1050 1100 1150 1200 1250 1300 1350 1400 1450 1500

Torque,T(Nm)

Wheel Rotational Speed, (rpm)

Graph of Torque against Wheel Rotational Speed (40 Hz)


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Figure 2.3: Graph of Power against Wheel Rotational Speed for f=40Hz

Figure 2.4: Graph of Efficiency against Wheel Rotational Speed for f=40Hz

60.0

65.0

70.0

75.0

80.0

85.0

90.0

95.0

100.0

105.0

1000 1050 1100 1150 1200 1250 1300 1350 1400 1450 1500

Efficiency,

(%)


Graph of Efficiency against Wheel Rotational Speed (40 Hz)

35.000

37.000

39.000

41.000

43.000

45.000

47.000

49.000

51.000

53.000

55.000

1000 1050 1100 1150 1200 1250 1300 1350 1400 1450 1500

PowerOutput,P(W)


Graph of Power against Wheel Rotational Speed (40 Hz)

Mechanical Power (W) Hydraulic Power (W)


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Figure 2.5: Graph of Torque against Wheel Rotational Speed for f=55Hz

Figure 2.6: Graph of Volume Discharged Rate against Wheel Rotational Speed

for f=55Hz

0.500

0.550

0.600

0.650

0.700

1300 1400 1500 1600 1700 1800 1900

Torque,T(Nm)


Graph of Torque aginst Wheel Rotational Speed (55Hz)

8.00

8.10

8.20

8.30

8.40

8.50

8.60

8.70

8.80

8.90

9.00

1300 1400 1500 1600 1700 1800 1900VolumeDischargedRate,Q(x10^-4m^3/s)

Wheel rotational Speed, (rpm)

Graph of Volume Flow Rate against Wheel Rotational Speed

(55Hz)


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Figure 2.7: Graph of Power against Wheel Rotational Speed for f=55Hz

Figure 2.8: Graph of Efficiency against Wheel Rotational Speed for f=55Hz

85.000

90.000

95.000

100.000

105.000

110.000

115.000

120.000

125.000

130.000

135.000

1300 1400 1500 1600 1700 1800 1900

PowerOutput,P(W)


Graph of Power against Wheel Rotational Speed (55 Hz)

Mechanical Power Hydraulic Power

60.0

65.0

70.0

75.0

80.0

85.0

90.0

95.0

100.0

1300 1400 1500 1600 1700 1800 1900

Efficiency,

(%)


Graph of Efficincy against Wheel Rotational Speed (55 Hz)


25/31

Sample Calculation

Given radius of drum brake, specific weight of water, pump frequency, f = 40Hz

Weight of load 1, Weight of load 2, Net load,

Torque,

Rotational speed of turbine, Angular Velocity,

Mechanical power,

Volume flow rate,

Hydraulic power,

Turbine efficiency,


26/31

DiscussionBy comparing both graph of torque, T against wheel rotational speed, , the graph

with frequency,f=55Hz (Figure 2.5) has higher torque range and wheel rotational speedrange as compared to f=40Hz (Figure 2.1). With the same wheel rotational speed, it is

found out that torque value for f=55Hz show higher readings as compared to f=40 Hz.

The machine pump rotates at higher frequency will pump higher volume of water,asserting a greater force on the wheel. Since the magnitude of torque is directlyproportional to the force and the radius magnitude is constant, the greater force will lead

to greater torque. The greater force will push the wheel to rotate at a higher rotational

speed and give the graph with frequency, f=55Hz (Figure 2.5) a higher torque readingrange and wheel rotational speed range as compared to f=40Hz (Figure 2.1). Besides,

with the same rotational speed, the one with a higher machine pump frequency will

greater amount of water being pumped, asserting a greater force on the wheel and give

higher torque reading. Both graphs show linear decline of the torque reading with the risein wheel rotational speed but the torque values obtained are widely separated from the

line of best fit for f =55 Hz (Figure 2.5). This may due to some experimental errors.

Based on the research, it is found out that the expected graph of torque against wheelrotational speed (Figure 2.9) should show a linear decline of torque value with the rise of

wheel rotational speed. The difference between the expected and experimental results

may due to errors in the experiments.

Figure 2.9: The expected graph of torque against wheel rotational speed.

For graph ofvolume flow rate, Q against wheel rotational speed, , the volume flow

rate decrease with the rise of wheel rotational speed. The higher the speed of water

supply, the less amount of water flow out from the nozzle. This will cause the wheel tohave a higher rotational speed. Since the volume of water supply is less, the water flow

out also at lesser volume. Hence the volume flow rate will decrease with the increase in

the wheel rotational speed due to the reduction in the volume of water flow in. Volumeflow rate and wheel rotational speed for f=55Hz (Figure 2.6) show higher readings as

compare to thef=40 Hz (figure 2.2). The machine pump rotating at higher frequency will

lead to a rise in the volume of water pumped. Greater force will be exerted on the buckets


27/31

of the wheel by the higher volume of water supply and this will lead to an increase in the

wheel rotational speed. At the same time, volume flow rate will also increase as the

volume of water supplied is greater which cause the volume flow out also higher.

For graph of power, P against wheel rotational speed, , the hydraulic power hashigher readings as compared to mechanical power for both f=40 Hz and f=55Hz. Themechanical power of the wheel is the power obtained due to the hydraulic power of the

water source. There is a possibility that the energy will experience losses when changes

from hydraulic to mechanical power such as frictional and sound power lost. Hence thereadings of the mechanical power show lower values as compared to the hydraulic power.

For f=40 Hz (Figure 2.3), the mechanical power line shows a quadratic curve with a

maximum value and curving upwards. This simply means that the power output will

increase with the rise of the wheel rotational speed. This will continue until it reach themaximum mechanical power produced at the optimum rotational. Any further increase in

the wheel rotational speed will not lead to a rise in power output but a decrease. The

hydraulic power line shows a right part of quadratic curve which curve upward, starting

with the maximum power output and start to decrease.

Besides, it is also noticed that at =1275rpm, the hydraulic power will be converted tothe maximum amount of mechanical power, about 47.5W. Forf=55 Hz (Figure 2.7), the

mechanical power line shows the left part of quadratic curve curving upward, starting

from the minimum power output and start to increase while the hydraulic power lineshows a right part of quadratic curve curving upward, starting with the maximum power

output and start to decrease. The wide deviation of points for mechanical points and the

line of best fit for f=55 Hz (Figure 2.7) are due to experimental errors. From the graph,

the optimum operational rotational speed whereby the maximum amount of mechanicalpower obtained from the hydraulic power is about 1790 rpm, producing 108W. Based on

the research, it is found out that the expected graph of power output against wheelrotational speed (Figure 2.10) should show a quadratic curve with the maximum valuewith the rise of wheel rotational speed. The difference between the expected and

experimental results may due to errors in the experiments.

Figure 2.10: The expected graph of power output against wheel rotational speed.


28/31

For the graph ofefficiency,against wheel rotational speed, , both graphs of f=40Hz and f =55Hz show the front part of the quadratic curve which curve upward,

increasing from the minimum value to maximum value. At the maximum efficiency, thisis the time where it has the highest mechanical power to hydraulic power ratio. For graph

of f=40 Hz (Figure 2.4), it has the highest efficiency at =1400rpm of =97% and forgraph off=55 Hz (Figure 2.8), it has the highest efficiency at =1790rpm of =91% Ingeneral, the efficiency of the machine withf=40 Hz (Figure 2.4) is higher than graph off=55Hz (Figure 2.8) but there are unacceptable situation whereby the efficiency is higher

than 100% when the wheel rotational speed at 1290rpm and 1318rpm. This may be due to

some experimental errors. Based on the research, it is found out that the expected graph

of efficiency against wheel rotational speed (Figure 2.11) should show a quadratic curvehaving a maximum value with the rise of wheel rotational speed. The difference between

the expected and experimental results may due to errors in the experiments.

Figure 2.11: The expected graph of efficiency against wheel rotational speed.

Experimental errors occur in the experiment leads to the deviation of the readings

obtained as compared to the expected results. The first error is the fluctuation of the

machines readingswhereby when taking the readings of loads, the readings fluctuate andthe exact value of the loads readings are hard to obtain. This may be caused by the

vibration of the operating motor and water flow through the pipe. These vibration will

affect the sensors and cause the instruments readings to fluctuate. This leads to lessaccurate net weight of load, torque and mechanical power readings. Besides, there is also

pipe leakage which may also contribute to the deviation of the experimental readings.

The zero errors also contribute to the experimental errors whereby the measuringinstrument show negative readings at the beginning of the experiment before the readingsare taken. The frictional force between the wheel and the wheel shaft also causes the

readings obtained to be less accurate. The old brake band unable to give a constant

friction with the wheel drum.


29/31

Errors and PrecautionThere are some errors in the experiment and precaution steps are required to improve the

experimental results. First, the experiment should be carried out for a few more times andthe average readings are taken to improve the experimental result. The readings should

only be taken when they are stable to give more accurate experimental results. The

installation of the damper in motor and pump will minimise the system vibration.Furthermore, new piping system should be designed with no leakages, smooth innerpiping and less bending, valves or other factors which will contribute to the minor head

losses and affect the hydraulic power obtained. Besides, the measuring instruments

should also be set zero before the readings are taken to avoid the zero errors. Furthermore,the contact area between the wheel and its shaft should be lubricated frequently to ensure

the minimum amount of friction subjected which affect the experimental readings. The

brake band should be replaced to improve the experimental result. The adjusting knob

used for adjusting the turbine speed is loose and this will cause the value of impellerspeed cant be set accurately. The adjusting knob can be replaced by using a digital

control system to control the speed which can improve the accuracy of the readings.

Conclusion

The Pelton Turbine will show different operational characteristics when the machine

pump is operating at different frequencies and different hydraulic pressure. At higherfrequency, it will have higher wheel rotational speed, torque, volume flow rate and power

output but lower efficiency. At lower frequency, it will have lower wheel rotational speed,

torque, volume flow rate and power output but higher efficiency. Graph of torque,volume flow rate, power output and efficiency against wheel rotational speed are drawn

for frequency, f=40Hz and 55Hz.


30/31

Extra Discussion

Characteristics Pelton Turbine Francis Turbine Kaplan Turbine

Types of

turbine

Impulse turbine Mixed impulse and

reaction turbine

Reaction turbine

Application High pressure head

and low flow rate

(mountain

hydroelectric)

Medium pressure

head and flow rate

(hydroelectric with

medium head and

flow rate)

Low pressure head

and large flow rates

(dams, tidal barrage)

Fluid flow

direction

Tangential flow

(Radial/ Axial flow)

Mixed flow Axial flow

Number of

runner blade

Absence More (16 to 24

blades)

Less (3 to 8 blades)

Law of Newton

applied

First, second First, third First, third

Difficulty tooperate and

assemble

Easy Difficult Difficult

Presence of

draft tube

Absence Presence Presence


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References

1. Pipe flow, Retrieved October 21, 2013, from

http://www.lth.se/fileadmin/tvrl/files/vvr120/13.pdf

2. SolteqDemonstration Pelton Turbine Model FM41, Retrieved October 21, 2013,

from http://www.solution.com.my/pdf/FM41(A4).pdf

3. Comparison of Pelton, Francis & Kaplan Turbine, Retrieved October 21, 2013,

from http://www.youtube.com/watch?v=k0BLOKEZ3KU

4. Fluid Mechanics Tutorial No.8A Water Turbines, Retrieved October 21, 2013,

from http://www.freestudy.co.uk/fluid%20mechanics/t8a203.pdf

5. Wiki.answers.com.Difference between francis and kaplan turbines?.

Retrieved October 1, 2013, from

http://wiki.answers.com/Q/Difference_between_francis_and_kaplan_turbines

6. Wikipedia.http://en.wikipedia.org/wiki/Francis_turbine

7. Dr. Inzarulfaisham Abd Rahim. (2013)Buku Makmal EML 331/2 Makmal

Kejuruteraan II Sidang 2013-14.Pusat Pengajian Kejuruteraan Mekanik Kampus

Kejuruteraan USM.

8. Yunus A. Cengel, John M. Cimbala. (2010).Fluid Mechanics Fundamentals and

Applications. Americas, New York: McGraw Hill Higher Education (Asia).
http://www.lth.se/fileadmin/tvrl/files/vvr120/13.pdfhttp://wiki.answers.com/Q/Difference_between_francis_and_kaplan_turbineshttp://wiki.answers.com/Q/Difference_between_francis_and_kaplan_turbineshttp://en.wikipedia.org/wiki/Francis_turbinehttp://en.wikipedia.org/wiki/Francis_turbinehttp://en.wikipedia.org/wiki/Francis_turbinehttp://en.wikipedia.org/wiki/Francis_turbinehttp://wiki.answers.com/Q/Difference_between_francis_and_kaplan_turbineshttp://www.lth.se/fileadmin/tvrl/files/vvr120/13.pdf

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