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Explain the working of a 2 stage velocity compounding impulse turbine curtis?
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What is a steam turbine?
It is an engine.A steam turbine is a heat engine that uses the expansion of steam passing through stationary nozzles and blades on a shaft to turn the shaft. The steam can move through the turbine axially (one end of shaft to the other end), radially (shaft to outer casing), or tangentially (around the outer edges of the turbine wheel). In an impulse turbine, the steam is expanded in nozzles and pushes the blades. In a reaction turbine the steam is expanded in the nozzles AND in the blades, the reaction of the expansion of the steam pushes away from the blades spinning the wheel in the process. The expansion of the steam is necessary to increase its velocity through the turbine.
Comparison between impulse and reaction turbines?
in the case of impule turbine total energy at inlet is kinetic energy and in case reaction turbine energy at inlet is kinetic and pressure......
What is the velocity of the outer turbine blade running at 3600 rpm the diameter of the turbine rotor is ten feet answe in mph?
1285.19 mph
Why compounding is necessary in steam turbine?
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What turbine does not require draft tube?
Draft tube is used to increase the pressure from the low turbine exit pressure to the pressure of the surrounding to which the fluid is rejected.Only reaction turbines require a draft tube as there is low pressure at the exit of the turbine,where as in an impulse turbine the pressure at the inlet and the exit is essentially the same, which is above the pressure to which the fluid is rejected and thus it require no draft tube.
What is the necessary of compounding in turbines?
compounding of turbines is necessary to make the turbines practically controllable.If compounding is not done the size of the turbine will be huge.Hence by pressure &velocity compounding the turbine becomes small in size &its velocity is also becomes controllable.
what is purpose of nozzle in steam turbine?
It sends hot gases from the combustion chamber to the 1st stage turbine blades at the correct angle and speed
What is steam velocity in turbine?
That is how fast the steam is actually moving in the turbine. For impulse turbines it is twice as fast as the turbine blades. In reaction turbines it is the same speed as the blades. Because the blades of a turbine cannot move faster than 4500 feet per second without self destructing as it overcomes the centripetal force of the turbine wheels, the steam turbine is designed such that no turbine will exceed more than ~1150 feet per second on its tip speed. Thus the steam velocity through the turbine will be less than ~1150 fps for a reaction turbine and less than ~2300 fps for an impulse turbine, or about ~1570 mph, more than twice the speed of sound.
What is the compounding steam turbine?
Velosity compounding:This is a combination of pressure-velocity compounding. Lets say you have superheated steam coming out of the boiler at 70 bar, which is suppose to drive a steam turbine. How many stages of blading required to reduce the pressure to acceptable exhaust pressure so that it does not overheat the condenser?Remember, when you reduce the pressure the kinetic energy increases so is the steam speed. In order to reduce the pessure you must have pressure compounded arrangement. In order to reduce speed you must have velocity compounded. So what is pressure componded?This is an array of nozzles and impulse blades laid out accordingly to mainly reduce the steam pressure as it pass through the respected stages.Notice the pressure drop gradually as it pass through a fixed blade stage, but the speed increases as it pass the same stage. The velocity compounded which is arranged so that you have nozzles,moving and fixed blades laid accordingly. As it enters the nozzle the pressure is dropped, steam velocity inctreased.Then it pass through moving blades which reduces the steam velocity but maintain steam pressure.Then the steam is pass through guide blades or fixed blades where further reduction in velocity but none in pressure.Last stage is moving blades where velocity is reduced but pressure is maintained. How is pressure-velocity compounding accomplished? Answers: It is a combination of pressure compounding and velocity compounding. Steam is expanded partially in a row of nozzles whereupon its velocity gets increased. This high velocity steam then enters a few rows of velocity compounding whereupon its velocity gets successively reduced. The velocity of the steam is again increased in the subsequent row of nozzles and then again it is allowed to pass onto another set of velocity compounding that brings about a stage-wise reduction of velocity of the steam. This system is continued.
Why velocity of flow will decrease with increase in peripheral speed of francis turbine?
the peripheral velocity of the turbine is the around velocity. the increase in the velocity of the peripheral will decrease the velocity of the flow towards the turbine
Diagram of gas turbine?
A diagram of an impulse turbine is in related links.
How steam turbines be classified?
1) Impulse turbine 2) reaction turbine
What do you mean by whirl velocity of turbine?
Whirl velocity of a turbine is determined by how fast the turbine can turn when it is moving. This is a factor considered with airplane manufacturing. Whirl velocity is the number of times in a second that a turbine can rotate, moving at a given speed.
Define two stage impulse turbine?
A two stage impulse contains 2 stages. One stage is a stator and rotor, therefore a 2 stage impulse turbine contains a stator-rotor-stator-rotor.
Why pelton turbine is called as impulse turbine?
Water is blasted at the buckets one by one or more jets mounted in the surroundings casing. Momentum is transferred from water to buckets and a torque is created, causing the wheel to rotate. That's why it is an impulse turbine.
What is a stage of an impulse turbine?
In an impulse turbine, the stage is a set of moving blades behind the nozzle. In a reaction turbine, each row of blades is called a "stage." A single Curtis stage may consist of two or more rows of moving blades.
What is governing of impulse turbine?
Basically governing of a turbine is controlling the speed of the turbine as the load keeps varying. The turbine needs to rotate at a constant speed. The governing of an impulse turbine is done by varying the jet of water that hits the buckets of the runner. This is done by using a spear arrangement in the pen stock. A pen stock is a type of pipe that provides the jet of water.
