2) This turbine can work easily at low discharge. 3)
It is very easy to assemble
. 4) 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 is better impulse or reaction?
Newton’s third law explains the energy transfer for
reaction turbines
. Reaction turbines are better fitted to higher flow rates or cases where the upstream fluid head (pressure) is low.
What is difference between impulse and reaction turbine?
The main difference between the impulse turbine and the reaction turbine is that,
in the former, there is a pressure drop across the fixed blades only
, whereas in the latter, there is a pressure drop across both the fixed and the moving blades.
What are the advantages of reaction turbine over Pelton wheel?
Reaction turbines and water wheels, a type of turbine, are very efficient machines. Because of their unique design, maximum energy is extracted from the flowing stream. This leads to offshoot advantages, such as
improved power transfer to pulleys or grinding stones
.
What is the advantage of impulse reaction turbine blades?
Impulse turbines are most efficient for use in cases where the
flow is low and the inlet pressure is high
. 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 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.
Why first stage of turbine is impulse?
The first turbine stage, however, is often an impulse stage for
controlling the steam flow and for rapidly reducing the pressure in stationary nozzles from its high steam generator value
, thereby lowering the pressure that the casing has to withstand.
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 turbine has highest efficiency?
Large Francis turbines
are individually designed for each site to operate with the given water flow and water head at the highest possible efficiency, typically over 90% (to 99%). In contrast to the Pelton turbine, the Francis turbine operates at its best completely filled with water at all times.
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.
Why it is called reaction turbine?
The nozzle-guide vanes only guide the flow for the rotors. The
turbine is driven by the reaction force resulting from the acceleration of gases through the converging blade passage
and, hence, the name.
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.
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.
What are the advantages and disadvantages of Pelton wheel turbine?
Advantages of Pelton Wheel:
The Pelton turbine is
the most efficient of hydro turbines
. It operates with a very flat efficiency curve. Each bucket splits the water jet in half, thus balancing the side-load forces or thrust on the wheel and thus the bearings. It operates on the high head and low discharge.
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.
Which principle is applicable for Pelton wheel turbine?
Pelton turbine – The basic working principle
Working principle of Pelton turbine is simple. When a high speed water jet injected through a nozzle hits buckets of Pelton wheel; it
induces an impulsive force
. This force makes the turbine rotate. The rotating shaft runs a generator and produces electricity.
