PART A : PELTON TURBINE
OBJECTIVE
To determine the characteristics of Pelton Turbine operation by using several speed.
LEARNING OUTCOMES
At the end of the course, students should were able to apply the knowledge and skills they have learned to:
Understands the basic operating system of the Pelton Turbine. Understands the factors which influence the efficiency of turbine.
THEORY
A Pelton Turbine characteristic operation curve can be derived by using the same method as a pump. It is because the usually assumed as an independent parameter when the plotting of power, efficiency, torque and discharge are carried out. Mechanical Power, Pm Power, Pm (watt) =Rotation =Rotation (τ , Nm , Nm)) x Circular velocity (ω , rad/sec). rad/sec). Where T= Force ( N ) x Radius (m (m)( Nm) Nm) and
2 radius / min min
60 sec/ min min
(rad/s) where, 1 revolution is equal to 2 radius. Meanwhile, Water Power, Pw = pgHQ pgHQ where p water density (100kg/ m 3 ), g is gravity constant (9.81 m/ s 2 ), H is head at inter point (m) and Q is flowrate ( m 3 /s). Wheel efficiency, minute’ is given given by
x
EQUIPMENT
Pelton Turbine Tachometer Stopwatch
%
Pm
Pw
x 100 .
To convert the unit of ‘rpm’ to ‘radians per
rpm = ( x revolution/min) = ( x x 2 radian)/min.
PROCEDURES
1. The Pelton Turbine equipment was put on the hydraulic bench and the water supply was connected to the turbine by the provided connecter. 2. The optic tachometer was tighten by using the clip. 3. Firstly, the turbine drum was free from any load (0.00N). 4. The valve controller was fully opened. Then the tachometer was leveled until the rotation reaches the maximum value of 2000 rotation/minute. 5. The reading of tachometer, flow rate, pressure at inlet point (H) and load,W 2 (N) were recorded. The brake equipment was put on the turbine.then the brake was leveled on the right spring at W1. The experiment started with the W 1 = 1.0 N . 6. All the readings was recorded in the table 6.1. 7. Step 3-6 were repeated with W varies in the range of 1.5N to 6.0N.
QUESTIONS
1. Plot graph of: a. The rotation power curve. b. Efficiency curve. c. Discharge versus motor speed.
(see the graph on the next page)
2. Give a comment on the graph obtained. Based on the experiment we have done, the first graph which is the graph rotation power curve show that at the beginning the rotation is increasing when the power is increasing but when it reach at the peak it start to decreasing but once again the rotation increase. For a second graph which is efficiency graph, the graph show that the efficiency is increasing when the value of RPM is decreasing. But at one time, the efficiency is decreasing even when RPM is decreasing. But then the efficiency will increase once again. For the third graph, which is the discharge versus motor speed, the graph is a linear graph which the value of RPM is recorded by optic tachometer is decreasing when the discharge is increasing.
3. Calculate the velocity where the maximum power is reached. Give your comment based on the level of maximum efficiency.
Mechanical Power, Pm = Rotation x circular velocity = τx
Circular velocity
=
28.74 0.105
= 273.71 rad/s
Value of velocity is influence the value of power. When velocit y is increasing, the power is also increase.
4. State 5 safety factors that have been taken in the experiment.
a) b)
Before switch on the pump, make sure the ball is already lifted. Make sure the data of pressure is only recorded when the highest pitch sound is produced. c) When recording RPM, make sure the laser from optic tachometer is attach on the drum brake.
DISCUSSION
There are a few error occurs in this experiment. The error must be avoided because it will influence the reading of the data recorded during the experiment. There are a few
The observer or student have a hard time to decide the highest pitched sound which is produce when valve controller been adjusted. The student did’t follow the safety factor that instructed by lecturer or technician who is incharged. Student did’t sure to selected the mostly repeated RPM that produce by optic tachometer. This situation happen because the device show many reading.
To avoid the error from occurs, here are few c aution step to follow such as:
Selected the most careful student among the member group to take role as observer.
CONCLUSION
Based from this carried out experiment, we could see that one of pelton turbine application is use in electric power supply plant. This happened due to the velocity influence increasing power, efficiency, torque and discharge are carried out. Firstly, get the value of pressure by the highest pitched sound produce by turbine. Secondly, get the value of load,W2. Then, get the value of RPM by record the velocity of drum brake. Finally, get the time of water to reach the fixed volume which is 5L.
APPENDIX
Measuring cylinder to measure the volume of water .
Optic tachometer to measure RPM.
Procedure how to use optic tachometer
Pressure meter head
The ball which control outflow and inflow of the water
