09V/09VI (095/096) Nuclear Submarine Thread

[Hendrik_2000]

Because they purposefully eliminated fro mteh spectrum the peaks. The commercial ships has a peak vibration frequency at (surprise, surprise ) 50 Hz .

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Let say by other ways ( I hope it is easy )
The 50 HZ generator makes 50 HZ noise.
400 Hz generator makes 400 Hz noise.
1000 Hz generator makes 1000 Hz noise.
Do you understand up to this point?

If you put together the above with the frequencies / attenuation that I calculated, then for a 50 Hz generator you need bigger and more complex vibration suppression than for a 1000 Hz. (later practically doesn't need any )

No, to make 20 MWe you need
64 tons of 50 MHz generator
8 tons of 400 Hz generator
3.2 tons of 1000 Hz generator.
Do you understand the mass-rpm(frequency )ratio of the generators?
It is within the high school knowledge.

3.2 tons of generator is half cubic meter, 8 tons is one cubic meter.
The generator on the pictures way bigger than this.
So, 50 HZ generator is very big, requiring complex noise suppression, 1000 Hz is very small, and doesn't need any noise suppression. Interesting ?

BS! you don't know a thing about submarine noise! SEE the sonar screen those bar
Read this. It clearly show that submarine noise DOES NOT CONSISTS OF SINGLE FREQUENCY CERTAINLY NOT THE MOTOR FREQUENCY.
Another thing this graph show is that submarine never run at the highest speed because it exacerbate the noise level and defeat the stealth character of submarine

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The discrete components are the most visible signs of the submarines' SL spectrum since they are detected even at low speeds, when submarines produce minimal noise. Moreover, the aggregate of the discrete components of the noise spectrum (the so called "acoustic portrait") which is unique for each submarine, may be used to identify the source.

Discrete lines in the 0.1-10 Hz band are caused by rotation of the propellers. This noise is difficult to suppress. Moreover, the noise from the propeller may be heard in the ocean at a distance of up to several thousand kilometers since absorption by ocean waters at this low frequency is negligible. The method of narrow-band filtration of the spectrum's discrete line at frequencies up to several Hz is the basic working principle for sonar systems for long-distance detection.

Discrete lines in the frequency band of several Hz to several hundred Hertz is associated with vibrations from the submarine's hull and power plant equipment. The most characteristic line in the SL spectrum is the peak at frequencies of 50 and 60 Hz for Russian and American submarines respectively, i.e., the lines which correspond to the basic frequencies of the submarines electric generators. The SL spectrum of first generation SSNs contained discrete lines at frequencies, which are multiples of 50 and 60 Hz, or in other words, harmonics of the basic frequencies. Specialists claim to have successfully registered up to 5 harmonics of basic frequencies. The spectrums of modern fourth generation submarines, those built at the end of the 1980's, do not contain discrete lines at frequencies greater than 100 Hz. This is justified to a lesser degree when the speed is less than 8 knots

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[Anlsvrthng]

BS! you don't know a thing about submarine noise! SEE the sonar screen those bar
Read this. It clearly show that submarine noise DOES NOT CONSISTS OF SINGLE FREQUENCY CERTAINLY NOT THE MOTOR FREQUENCY.
Another thing this graph show is that submarine never run at the highest speed because it exacerbate the noise level and defeat the stealth character of submarine

It proving that the military never intended to use the submarines as musical instrument, and even they try to suppress the noise of it.

The 50 Hz (that is NOT 50, but should 400-1000 HZ) should be heard in a narrow frequency if they make the submarine to resonate on that frequency.

But they doing the opposite, design the submarine to NOT resonate on that frequency.

 

[taxiya]

Ok I make mistake 34.2 out put at the shaft assuming the diameter is 10 the calculation that I quote show 30 MW so I don't know where you got 38 or where is this 50 MW come from ?
Based on which diameter ? and what speed and where did you get this speed form reference Show me in this forum. My computer crash I don't have excel now
Do Hand calc using speed of 30mph that is the bench mark and not 30 KNot

Ok, it is being dragged for too long, let me give a last try. I have downloaded the article, in it on page 8, I quote

EXAMPLE
Consider a column of salt water of diameter D = 10 m, moving with a power of 30 MW. Its theoretical attainable speed at that power level, without drag or friction is:

30MW shaft power gives 17.7knots

I put the same formula in excel and used solution finding function. To get 20+ knots as LA claimed to be, I got 50MW shaft power.

At the end of page 11

The S1C reactor used an electric drive rather than a steam turbine like in the subsequent S5W reactor design rated at 78 MWth and a 93 percent U235 enriched core that was the standard in the 1970s. The S6G reactor plant was rated at 148 MWth and the D2W core was rated at 165 MWth.

Now, about LA
LA uses S6G and later model has D2W core which rated at 165 MWth which is 55MW (165/3, 30% being common efficiency for maritime nuclear plant). Considerring that is also to generate electricity for other equipment (I took 10%), it leaves 50MW shaft powers for the propeller. That 50MW is generated by two turbines, this gives each turbine 25MW for the propeller.

Now, about supposed 09 type and the 20MW class steam turbine generator.
This is ONE turbine. Two (as you proposed) would give 40MW. This is a generator. Its electricity is for both propelling motor and other equipment, so I have to take away 10% as I did to LA. The end result is 40x90%=36MW

Note, I said 36 not 38.

My calculation is purely based on the same formula from the article. I don't question the author's accuracy or estimation. I do agree that his writing is very close to reality and his formula is accurate.

I did not question the Chinese capability of building big steam turbine either. Actually as far as I know, PLAN has steam turbine rated at 35MW (type 453B) which drives type 051 destroyer. So there is no problem in getting 30MW per turbine. My question was always "does that 20MW CLASS mean 20MW or anything between 20 and 30MW?" The concern is not turbine itself, it is the electrical generator which is a first time for China in this class.

 

[asif iqbal]

can we cut the BS with these equations ?

its just getting silly

have not taken into account key parameters and yet calculating speed from power? ridiculous

what about friction, temperature, wind speed, sea state and how about dielectric constant

 

[Anlsvrthng]

can we cut the BS with these equations ?

its just getting silly

have not taken into account key parameters and yet calculating speed from power? ridiculous

what about friction, temperature, wind speed, sea state and how about dielectric constant

The calculation is correct.
The shape/surface of the submarine has lot of effect, but the sheer magnitude of the required power can be calculated like this.

And the wind speed has minor effect on a submarine : P

 

[taxiya]

can we cut the BS with these equations ?

its just getting silly

have not taken into account key parameters and yet calculating speed from power? ridiculous

what about friction, temperature, wind speed, sea state and how about dielectric constant

Without these "BS", you would not have a slightest clue of required power for these submarines to reach their required speed. Engineering can be boring and brain-killing, but ridiculous? .

Considering frictions, the speed will be lower. Wind is not much concern since you know they are subs . Dielectric? are you talking about subs and ships?

 

[asif iqbal]

Please I have a degree in maths I don’t need online lessons

 

[Anlsvrthng]

Please I have a degree in maths I don’t need online lessons

It is not a lesson, only pointing to the flaws of your logic.

And it is not about math, but applied physics .

 

[Anlsvrthng]

No it's rather how you applied BS into your calculations and call it "physics" or magic math.

?
The submarine speed calculation is not mine.
I just agreed with it.

Or my agreement makes it dirty ? : D

 

[Anlsvrthng]

So you agreed that you applied your fake demonstrations and allegations through math?

?
Mate, this topic is about submarines, not personal insults.