experiment 4 Heat Conduction in Metals 2

· To determine the characteristic curves of the Francis Turbine at varying speed.

· To Study behavior of torque, volumetric Flow Rate by changing Guide Vane Position

· To draw the graph between speed vs flow rate, speed vs mechanical and hydraulic power, speed vs efficiency.

Turbines are subdivided into impulse and reaction machines. In the impulse turbines, the total head available is converted into the kinetic energy. This is usually accomplished in one or more nozzles. In the reaction turbines, only some part of the available total head of the fluid is converted into kinetic energy so that the fluid entering the runner has pressure energy as well as kinetic energy. the pressure energy is then converted into kinetic energy in the runner.

The Francis turbine is a type of reaction turbine that was developed by James B.Francis .Francis turbines are the most common water turbine in use today. They operate in a water head from 40 to 600m and are primarily used for electrical power production. The electric generators which most often use this type of turbine have a power output which generally ranges just a few kilowatts up to 800 MW.

· Francis Turbine

· Potentiometer

· Pump

Figure 1

Figure 2

Figure 3

PUMP

1. I Set the desired guide vane position.

2. With the potentiometer, we set the speed of the pump, so the pressure is at 1. 5bar.Control the turbine speed depending on the requirement.

3. We Recorded or Noted the following Values;

· Torque

· Volumetric Flow

· Inlet pressure

· Outlet pressure

Repeating the procedure at different guide vane positions

Figure 4

Figure 5

Figure 6

Figure 7

Pmech(Watts)= M x N x

From table 2 Putting M=471 (liters/min)

N=1000 (RPM)

Pmech = 471 x 1000x

Pmech = 645.7 watt

Phyd(Watts)=1.66 x ∆p x Q

Putting ∆p=1.50 (bar)

Q=471 (liters/min)

Phyd = 1.66 x 1.50 x 471

Phyd = 1172.2 watt

Efficiency ɳ = (Pmech / Phyd )x100

ɳ = 55.0%

In this lab we have to determine the characteristic curves of the Francis Turbine by varying its speed and changing the guided vane position.

And then we Study behavior of torque, volumetric Flow Rate by changing Guide Vane Position, then we draw the graph between speed vs flow rate, speed vs mechanical and hydraulic power, speed vs efficiency

From the table and graph we see that when the

Guided Vane at position 3 when we increase the speed volumetric flow rate torque and Hydraulic power decreases while Mechanical Power and efficiency increases up to 1250 RPM and then start to decrease from 1250 to 1700 rpm. and the maximum efficiency 56.4% we achieve when we have speed 1250.

Guided Vane at position 5 when we increase the speed, torque decreases, while volumetric flow rate, hydraulic power, mechanical power and efficiency increases up to 1250 also when we further increase the speed volumetric flow rate, hydraulic power, mechanical power and efficiency decreases up to 1700. and the maximum efficiency 63.39% we achieve when we have speed 1250

Guided vane at position 7 when we increase the speed, torque decreases, while volumetric flow, hydraulic power, mechanical power and efficiency increases from 1250 to 1500 while when speed further increases from 1500 to 1700 mechanical power and efficiency start to decrease and the maximum efficiency 66% we achieve when we have speed 1500 which is overall maximum efficiency.

The possible and non-removable error which affect our results were atmospheric pressure, friction between inner surface of penstock and water which we can calculate from Darcy equation but in this experiment, we neglected all type of Darcy frictions. One of the main errors in the excrement is the pressure 1 in Potentiometer nope it was over used and unstable therefor the reading varies each time.

The fluctuation of the pressure 2 digital indicator which will close error in the result later.

In this experiment we determined the characteristic curves of the Francis Turbine at varying speed, and Study behavior of torque, volumetric Flow Rate by changing Guide Vane Position than draw the graph between speed vs flow rate, speed vs mechanical and hydraulic power, speed vs efficiency so we concluded from the results that when we change the position of guide vane and speed our results get change accordingly we can get maximum efficiency when the guided vane is at position 7 and at speed 1500RPM and minimum efficiency of 32% when guide vane is at position 3 at speed of 1700 rpm.

[1] R.K. Rajput, “Fluid Mechanics and Hydraulic Machines”, Laxmi Publications (P) Ltd.

[2] R. K. Bansal,” Fluid Mechanics and Hydraulic Machines”, Laxmi Publications (P) Ltd.

[3] D. S. Kumar,” Fluid Mechanics and Hydraulic Machines”, Laxmi Publications (P) Ltd.New Delhi (India).

[4] Yunus A. Cengel and John M. Cimbala, “Fluid Mechanics Fundamentals and Applications” McGraw Hill.

[5] D. S. Kumar, “Fluid Mechanics & Fluid Power Engineering” S.K. Kataria Publications.

[6] C.P. Kothandaraman & R. Rudramoorthy” Basic Fluid Mechanics” New Age Publications.

Figure 8

Figure 9

Figure 10

Figure 11

Volumetric Flow Rate VS Speed

Speed(RPM)

Volumetric Flow Rate liters/min,

Hydraulic Power VS Speed

Speed (RPM)

Hydraulic Power (WATT)

Mechanical VS Speed

Speed

MECHANICAL POWER

Efficiency VS Speed

Speed (RPM)

Efficiency ɳ (%)

© Australian College of Kuwait 2018

School of Engineering Mechanical Engineering

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