CV-17 Shandong (002 carrier) Thread I ...News, Views and operations
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Hendrik_2000
Lieutenant General
Well if I am not wrong some one mention that it is turbo charged well the term should be forced draft fan for boiler
From the prospective of air circulation that should result in smaller exhaust stack
But if you look closely at the stack there are en-train opening on the side of the stack I assume that is to reduce the heat signature of the stack by cooling heat exhaust with cooler en train air. And the size of stack + navigational deck determined the size of the island.
Now it also need intake air duct for boiler combustion
Those are probably boiler room intake fans to supply air to the steam boiler furnaces.
Look at the American kitty hawk class carriers from the 1960s. These also had high pressure/temp oil fired steam boilers, feeding a somewhat more powerful steam plant than on the Kuznetsov, Yet their islands accommodated the exhaust uptake, boiler air intake, and control spaces in an island much more compact than on the Liaoning/shangdong.
Hendrik_2000
Lieutenant General
Yes increase velocity mean increase in air mass that can be burned resulting in higher steam temperature But forced draft fan increase the velocity of flue gas and so it can it expel more flue gas per sq area . Remember mass of gas/time is equal velocity X area. Assuming the same equal of mass over time that need to be expelled, having increase velocity mean reduced area !
Here is the lay out of typical ship stack. It clearly show the stack is being cooled with entrain air
Here is the lay out of typical ship stack. It clearly show the stack is being cooled with entrain air
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Hendrik_2000
Lieutenant General
I don't think the FD fan has anything to do with the size of boiler
The amount of air in any combustion is determined by stochoimetry of combustion Adding more fuel will increase the heat but not adding air !
Due to restricted volume in ship and they must use FD fan to meet the stoichiometry of combustion
FD fan increase the pressure in the boiler and ID fan decrease the pressure in the boiler for added safety
FD fan is preferred because it does not exposed to heat therefore easier maintenance
Stack design is governed by temperature of exit gas and the profile of the plume.
The amount of air in any combustion is determined by stochoimetry of combustion Adding more fuel will increase the heat but not adding air !
Due to restricted volume in ship and they must use FD fan to meet the stoichiometry of combustion
FD fan increase the pressure in the boiler and ID fan decrease the pressure in the boiler for added safety
FD fan is preferred because it does not exposed to heat therefore easier maintenance
Stack design is governed by temperature of exit gas and the profile of the plume.
Hendrik_2000
Lieutenant General
The floater are installed new white bar above the APAR
Fuel combusts in the presence of atmospheric oxygen. Burning more fuel at the optimal ratio with oxygen requires more oxygen and more air. How much power a boiler of a given design boilers can generate by burning fuel is therefore limited by the rate at which the boiler can ingest air. Without forced draft, a boiler of a given size and design can only naturally ingest air up to a certain rate. Force draft allows more air to be supplied to the boiler than the boiler of a given size can ingest through natural draft.
Hendrik_2000
Lieutenant General
I think you are confusing Otto cycle with Rankine cycle
In Otto cylce (internal combustion engine) adding turbo charge will increase the air and rate of combustion which in turn add more energy to the piston because hot air is the medium and directly acted on the piston. So for the same volume it generate more power resulting in smaller engine!
But in Rankine cycle power is created in 2 stages Heat is used to converted water to steam which in turn fed to steam turbine and drive the generator. Adding more heat will only result in more WET steam generated.But the amount of steam admitted to the turbine is limited by governing turbine control valve!
Or else you will get steam turbine over run!. Here steam is the medium to generate power and not the air
Power is depend on the quality of steam the higher the temperature and pressure the higher is the availability of energy.
The way to get higher pressure and temperature steam is to add Superheater!. Reheater, FW heater
If more power is demanded heat is used to increase flue gas temperature and increase steam quality.
It is demand based
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