FRANCIS TURBINE - Constant Speed
Objective
To conduct the performance test on Francis turbine under constant speed.
Apparatus used:
Francis Turbine setup with Centrifugal Pump, Pressure Gauges, Weighing Balance with Weights, etc.
Description Francis turbine: is a type of water turbine. It is an inward-flow reaction turbine that combines radial and axial flow concepts.
Cavitation: is a phenomenon which manifests itself in the pitting of the metallic surfaces of turbine parts because of the formation of cavities.
Start the pump by pressing the start button.
Select the speed, then apply the weight on the pan and note the spring balance reading.
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 × gRotate the inlet valve and insert the tachometer.
Speed of motor (N)=
Note the supply head reading.
Supply pressure =
Supply head (Hs) =
Note the vaccum head reading.
Elevation difference, z = 0.45m
Vaccum pressure =
Total pressure =
H (m) = Hs + zTake the hook gauge reading to find the discharge.
Initial reading (water level till crest) =
Final reading =
Head of water =
Actual discharge, Qact =
Qact (m3/sec) = 2⁄3 × Cd × l × √(2g) × h(3⁄2)- Cd: Co-efficient of discharge: 0.6
- l: Length of the wire = 0.47m
Observation
Actual discharge, Qact =
Speed of motor (N) =
Torque (τ) =
Total pressure (H) =
Specific Weight of water (γ) = 9810N/m3
Result
Input power =
Input Power (W) = γ × Qact × 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.
