PELTON TURBINE - CONSTANT SPEED
Objective
To conduct performance test on Pelton wheel under constant speed and to plot the operating characteristics.
Apparatus used:
Pelton Wheel setup with Centrifugal Pump, Pressure Gauges, Spring Balance with Weights, etc.
Description Impulse turbine: is a turbine that is driven by high velocity jets of water or steam from a nozzle directed on to vanes or buckets attached to a wheel.
Reaction turbine: is a type of turbine that develops torque by reacting to the pressure or weight of a fluid.
Gross head (Hg): It is the vertical difference between headrace and tailrace.
Net head (H): is the actual head available at the inlet of the turbine to work.
Start the pump by pressing the start button and select the speed.
Apply the weight on the pan and note the spring balance reading for the corresponding applied weight.
Radius of brake drum (R) = 0.15 m
Dead weight of the pan (W) =
Spring balance reading (S) =
Torque (τ) =
τ (N-m) = (W - S) × R × g
Set the speed of the motor to be constant.
Speed of motor(N) =
Note the head of water.
Delivery pressure =
Delivery head (Hd)=
z = 0.33m
Total head, (Hd) + z =
H (m) = Hd+ zNote the V- notch reading to find the discharge.
Initial reading (water level till crest) =
Final reading =
Head of water (h) =
Discharge, Qact =
Q (m3/sec) = (8⁄15) × Cd × √(2g) × tan(θ/2) × h(5⁄2)- Cd: Co-efficient of discharge: 0.6
- θ: Apex Angle: 90°
Observations
Gate opening = 50%
Specific Weight of water (γ) = 9810N/m3
Actual discharge, Qact =
Constant head (H) =
Speed of motor (N) =
Torque (τ) =
Result
Input power =
Input Power (W) = γ × Q × HOutput power =
Output Power (W) = 2 × π × N × τ⁄60Efficiency =
Efficiency (%) = Output Power⁄Input Power × 100Repeat the same steps by increasing the weight on the hanger gradually
Characteristic Curves
Trial =
Both ends of the pipe must be trimmed to ensure parallel faces.
