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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 effect on a steam turbine if the system is running in under frequency?
It results in reduced ventilation and affect the turbine more than the generator.
What is turbine windage protection?
when steam flow blockage occured in steam turbine due to damage of blades/nozzles than steam temperature will increase so protect the turbine from high temperature this protection is introduced.
Why you maintain gland steam temp in steam turbine power plant?
gland steam temp should be nearer to less than turbine lub. oil flash point.
Why is the steam turbine generally more efficient than the piston-type steam engine?
less moving parts, each of which subtracts from total energy output
Why the steam turbine needs preheating before the operating?
there are stages, fixed blades on the turbine shell and rotating blades on the rotor. They are very close together sooo, because the steam enters at one end of the turbine it heats that area first and it expands the metal there faster than at the other end causing it to rub. if you heat it slowly the turbine casing and the rotor grow at ~ the same rate so the stages don't rub together. If you heat too quickly,by just admitting a high volume of steam, the rotor heats up to fast, because of it has less metal to heat up, it rubs the fixed blades. this is called going long (the rotor is longer than the tolerances between the fixed blades on the casing)
What is steam turbine governor valve?
In large turbines, a valve controls steam flow to groups of nozzles. The number of open valves controls the number of nozzles in use according to the load. A bar-lift or cam arrangement operated by the governor opens and closes these valves in sequence. Such a device is a multi-port valve. Using nozzles at full steam pressure is more efficient than throttling the steam.
Why vacuum is created in condenser on steam turbine?
Firstly, vacuum is being created in turbine exhaust and condenser rather than being required. It is created to reduce the back-pressures and to improve the turbine efficiency. Also, with vacuum the designers can design large size last stage blades of LP turbine for maximizing the turbine output.
Could you explain why connect gland steam area of HP turbine with reheat inlet line of IP TURBINE?
BECAUSE IF YOU DIDN'T TEMPERATURE AND PRESSURE DROPS WOULD ALREADY BE TOO BIG TO ALLOW 2 EXTRA STAGES OF TURBINES (IP AND LP'S). EVIDENTLY TO RE-CIRCULATE STEAM BACK TO BOILER AND ON TO IP TURBINE IS MORE COST-EFFECTIVE (I.E.: MAKES YOU GAIN MORE MONEY) THEN PERHAPS NOT BEING ABLE TO ADD ANOTHER 2 STAGES BUT ONLY ONE (I.E.: IP). THIS WAY YOU CAN MAKE SURE TO EXPLOIT ALL ENERGY OF THE STEAM FLOW. IF YOU DIDN'T REHEAT LOSSES WOULD BE GREATER THAN GAINS pleas be more clear in your answer and tll mw th benifet of the hp & lp glands
Why are number of compressor stages more than turbine stages in a jet-engine?
Flow does not like the pressure gradient it sees going into the compressor and is therefore, more likely to separate (causing flow separation). Therefore, a more subtle increase in pressure through each stage is needed in the compressor. The turbine does not see this problem.
Why tripping value of axial shift of steam turbine is more than turbine rotor float?
axial shift depends upon the gap between rotot blade and fixed blade , not on float
Are steam engines still being used?
Steam engines presently produce more power than all other types of engines combined. Most steam engines take the form of the steam turbine engine. The steam turbine is responsible for generating about 86% of the electric power used on this planet. Reciprocating steam engines are still in use for limited applications, but are generally considered obsolete. Steam engines, either the piston or turbine type were used on most big ships until recently, and there are still a few steam locomotives about.
