Impulse turbines change the direction of flow of a high velocity fluid or gas jet . ... Reaction turbines develop torque by reacting to the gas or fluid’s pressure or mass. The pressure of the gas or fluid changes as it passes through the turbine rotor blades.
What is the definition of the impulse of a reaction turbine?
The impulse turbine is the simplest type of turbine . It consists of a row of nozzles followed by a row of blades. The gas is expanded in the nozzle, converting the high thermal energy into kinetic energy.
What is meant by impulse turbine and reaction turbine?
As mentioned above, while an impulse turbine is capturing energy at only the single point where the water jet is hitting it , a reaction turbine is capturing energy across the whole wheel at once—which is why a reaction turbine in a hydroelectric plant can produce more power than an impulse turbine of the same size.
What is the difference between impulse and reaction steam turbine?
The main differences between Impulse and Reaction turbines are, all hydraulic energy is converted into kinetic energy by a nozzle in the Impulse turbine and whereas In Reaction turbine Only some amount of the available energy is converted into kinetic energy.
What is the principle of impulse turbine?
Working Principle of Impulse Turbine
In these turbines, the static pressure inside the runner is constant, and the turbine runner is at atmospheric pressure . The runner spins in the air, and the fluid is sprayed to the blades through the nozzle to exchange energy with the turbine.
Which is an example of impulse turbine?
Example: Pelton wheel turbine . Pelton Wheel Turbine: It is a tangential flow impulse turbine in which the pressure energy of water is converted into kinetic energy to form a high-speed water jet and this jet strikes the wheel tangentially to make it rotate.
Why it is used in reaction turbine?
Advantages of Reaction Turbine:
The reaction turbines use oil-free exhaust systems. It has a small size. It has a high capacity to use high temperature and high pressure . This type of turbine has a high working speed.
Where is turbine used?
Turbines are used in many different areas, and each type of turbine has a slightly different construction to perform its job properly. Turbines are used in wind power, hydropower, in heat engines , and for propulsion. Turbines are extremely important because of the fact that nearly all electricity is generated by them.
Which turbine has highest discharge?
Pelton has high head and low discharge. Explanation: Based on heads and discharges, turbines are classified into Pelton, Francis or Kaplan. Kaplan has low head and high discharge. Explanation: Francis turbine is a widely used turbine.
How many types of reaction turbines are there?
Reaction based turbines include three subtypes : Francis turbine, propeller turbine (bulb turbine, Straflo turbine, Kaplan turbine types), and kinetic turbine.
Which is the impulse turbine?
An impulse turbine has one or more fixed nozzles through which pressure is converted to kinetic energy as a liquid jet(s) – typically the liquid is water. The jet(s) impinge on the moving plates of the turbine runner that absorbs virtually all of the moving water’s kinetic energy.
Why it is called impulse turbine?
Unlike other types of turbines which are reaction turbines, the Pelton turbine is known as an impulse turbine. This simply means that instead of moving as a result of a reaction force, water creates some impulse on the turbine to get it to move .
What are the advantages of impulse turbine?
- This turbine has high efficiency.
- This turbine can work easily at low discharge.
- It is very easy to assemble.
- This turbine can be adjusted according to the flow rate condition. At high flow rates multiple nozzles are used and at very low flow rates single nozzle is used.
Which turbine has highest speed?
Which turbine has highest speed? Explanation: Francis turbine has a specific speed of 60 to 300 rpm. Specific speed of Pelton turbine is lowest. Speed of Kaplan turbine is 2 to 3 times more than that of Francis turbine.
Which principle is used in hydraulic turbine?
The principle of a hydraulic turbine is based on Newton’s second law of motion . It states that the force is directly proportional to the change in momentum. If there is any change in the momentum of the water, then a force is generated as a result.
What is specific speed of turbine?
The specific speed value for a turbine is the speed of a geometrically similar turbine which would produce unit power (one kilowatt) under unit head (one meter) . The specific speed of a turbine is given by the manufacturer (along with other ratings) and will always refer to the point of maximum efficiency.
