Skywatcher
Captain
Kyle also made the mistake of conflating "lprobable performance floor" of the Type 095 SSGN with the likely general performance of said submarine.
09III/09IV (093/094) Nuclear Submarine Thread
- Thread starter SinoSoldier
- Start date
Blackstone
Brigadier
Do you have any information on Chinese pump progress for their SSN/SSBN projects? I recall an article from Andrew Erickson saying that was one of the primary noise sources on PLAN nuclear submarines.
Henry K seems to think that the new nuclear submarines will use a reactor with natural circulation (using the heat generated by the reactor to circulate the coolant) instead of pumps (at least for normal situations, I'm sure there will be pumps as a fallback solution). If that is true this would eliminate pumps as a main noise source unless they switch to water jet propulsion.
China has recently disclosed that reactor with natural circulation has been successfully developed , and in fact was installed on its second-generation SSN/SSBN (093/094). The achievement is recognized by the government and the team that developed the technologies led by Mr Zhang JinLan was awarded the 2016 First-Class China Awards for Science and Technology. Mr. Zhang is the deputy director of Institute 719, the primary research institute of CSIS responsible for designing China's SSN/SSBN.
Mr. Zhang JinLan is profiled in the magazine:
Here is the official on Mr. Zhang and his team, in Chinese.
The relevant paragraph on natural circulation reactor:
Here is the corresponding Google translation:
Hendrik_2000
Lieutenant General
Right anyone who is ever close to process pump, should know that pump noise is unbearable even with ear plug
No matter how advanced the bearing is, can't avoid noise because there is always slight runoff and that is the one that cause the noise
So this news should completely "DEBUNK" the myth or slander that Chinese submarine is noisy without proof other than guesstimate
I am not surprise that they have this kind of reactor for type 93/94
We know that the propeller is of modern design another main source of noise.And anechoic tiles are installed on tear drop shape hull. Plus they put all the machinery on the raft
Also the fact that each one of type 93 is different than the previous version, that alone should tell us that they have design of progressively quieter submarine
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Blackstone
Brigadier
I wouldn't say the news "DEBUNK" noisy PLAN SSN/SSBN, because they might be for the older 93/94 and not updated ones. Second point is the message in Weig's post said pumps are ONE of the main noise generators, so unless Chinese submarine engineers solved all major noise sources, PLAN nuclear submarines may still be noisy relative to their western counterparts.
Hendrik_2000
Lieutenant General
Pump is THE Major source of noise I already lay it out for you there are basically 3 source of noises Engine, propeller, hydrodynamic source of noise .
Propeller noise is due to cavitation (small bubble implode). As the propeller velocity increase the pressure drop causing vapor to grow and separate then as the pressure increase it will collapse Causing noises(conservation of mass and energy) .
When the cavitation bubbles collapse, they force energetic liquid into very small volumes, thereby creating spots of high temperature and emitting shock waves, the latter of which are a source of noise. The noise created by cavitation is a particular problem for military , as it increases the chances of being detected by .
So the trick is to reduce the speed But if you reduce the speed you don't get thrust because of friction So the solution is to design high efficiency propeller.Slow but high thrust. The equation of it is well known . The devil is in manufacturing You just cannot do the volute by hand machining. You need CNC machine
Long time ago US and Japan has the lock hold on those machine and they put embargo on those CNC machine
But now China now can built 7 axis CNC for propeller machining I have the photo. And ironically now China has the lion share of world market for CNC machine. If you look into new Chinese submarine propeller they are of modern design
Now shroud will improve the noise further by containing the cavitation within the shroud .
The other source of noise is Hydrodynamic friction between the hull and water. But generally modern hull design of teardrop and symmetrical hull reduce this noise. Minimum protrusion also help
The design is more of an art. But nowadays they use finite element to predict the noise and China definitely has the tool of supercomputer and first class hydrodynamic engineer , programmer to built the analytical tool
The next source of noise is rotating machinery like pump, compressor etc. To get around it they put it on the raft and isolate from the submarine structure by having active cancelling mechanism to cancel the vibration . We know China has the technology
The acoustic signature can be reduced by
- fitting of machinery with the best possible and designed to produce a minimum of noise.
- decoupling the machinery from the hull by mounting machinery on rubber mounting blocks.
- designing to reduce cavitation, this led to the development of large slow turning propellers, today there is a preference now for over propellers.
- the fitting of to the hull, however ill fitting and loose anechoic tiles can themselves be a source of noise.
- hydrodynamic efficiency to minimise the perturbation of water.
- care in minimising protrusions from the hull.
So all in all the noise should be comparable to the best in the world
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Blackstone
Brigadier
This sentence is the bottom line, and the word 'should' (your word, not my) is the biggest problem. I follow your argument no-pump cooling, better propeller and shroud, plus supercomputer-assisted designs make submarines quieter. OK, let's say you're right on all three, how then do you arrive at the conclusion new or upgraded PLAN SSN/SSBNs are on par with the best in the world (that means the USN boats)? Just how quiet do you think new PLAN nuclear submarines are? What do you know of US SSN and SSBNs? Without more data, I don't know how you could accurately the claim.
Hendrik_2000
Lieutenant General
If you notice I didn't have number but based on those fact that China submarine has more or less the same technology as the best So the noise should be not to far away
Again pump is major source of noise,once you eliminate that the rest is easy
Hendrik_2000
Lieutenant General
Here is the article about type 93
观察者网军事评论员表示，拥有大质量导弹发射能力的我国第二代核潜艇，应当就是094型弹道导弹核潜艇，装备12枚巨浪-2潜射导弹。早年中国第一代核潜艇在噪音控制水平上由于技术限制，事实上是非常糟糕的。处于航行状态的核潜艇不可能采用常规潜艇那样关闭主发动机降噪的方式来关闭核反应堆，使用静音的电动机来驱动。如果核反应堆不具备自然循环能力，为了保证安全，反应堆的主泵是不能关闭的，这会导致潜艇在不需要进行高速航行的时候出现不必要的噪声来源。而具备自然循环能力的反应堆，在一定功率值以下时，不需要开启主泵就能维持反应堆一回路的正常运转，保证反应堆安全的同时为潜艇输出所需要的推进和发电功率。 而核潜艇的日常巡航过程中，不会经常处于非常高的航速，如果反应堆具备自然循环能力，那么潜艇的大部分航行时间都可以处于一个较低的噪声状态。同为我国第二代核潜艇的093型核潜艇与094采用了一样的动力系统配置，曾有传言称，该型潜艇在国际海域巡航时表现出的静音能力远远超过西方国家之前的想象，这其中降噪贡献最大的应当就是该型艇的核反应堆具备自然循环能力。 当然，093和094的反应堆毕竟只是中国研发的第一种具备自然循环能力的船用反应堆，在设计和技术水平上与国际先进水平相比尚有不足，不开启主泵状态下的反应堆输出功率所能提供的航速相比美国的“海浪”和“弗吉尼亚”差距还很明显。不过值得期待的是，中国下一代核潜艇必将使用具备更强自然循环能力的核反应堆，甚至达到国际先进水平。
Google translation
Observer network military commentators said that with large-scale missile launch capability of China's second-generation nuclear submarine, it should be 094-type ballistic missile nuclear submarines, equipped with 12 waves -2 submarine missiles. Early China's first generation of nuclear submarines in the noise control level due to technical constraints, in fact, is very bad. A nuclear submarine in a voyage state can not use a conventional submarine to shut down the main engine noise reduction way to close the nuclear reactor, using a silent motor to drive. If the nuclear reactor does not have the natural circulation capacity, the main pump of the reactor can not be closed for safety. This will cause the submarine to generate unnecessary noise when it is not necessary to carry out high speed voyage. With the natural circulation capacity of the reactor, below a certain power value, do not need to open the main pump can maintain the normal operation of the reactor loop to ensure that the safety of the reactor at the same time for the submarine output required propulsion and power generation. The submarine's daily cruise process, not often at a very high speed, if the reactor with natural circulation capacity, then the submarine most of the voyage time can be in a low noise state. With the second generation of nuclear submarines in China's 093 nuclear submarines and 094 using the same power system configuration, there have been rumors that the submarine in the international sea cruise to show the mute ability far beyond the Western countries before the imagination, which Noise reduction should be the largest contribution to the type of nuclear reactor with natural circulation capacity. Of course, the reactors of 093 and 094 are only the first marine reactors with natural circulation capability developed by China. There is still no shortage of design and technical level compared with the international advanced level. Do not turn on the reactor output power in the main pump state. Can provide the speed compared to the United States "waves" and "Virginia" gap is still evident. But it is worth looking forward to is that China's next generation of nuclear submarines will use a stronger natural circulation capacity of nuclear reactors, and even reached the international advanced level.
观察者网军事评论员表示，拥有大质量导弹发射能力的我国第二代核潜艇，应当就是094型弹道导弹核潜艇，装备12枚巨浪-2潜射导弹。早年中国第一代核潜艇在噪音控制水平上由于技术限制，事实上是非常糟糕的。处于航行状态的核潜艇不可能采用常规潜艇那样关闭主发动机降噪的方式来关闭核反应堆，使用静音的电动机来驱动。如果核反应堆不具备自然循环能力，为了保证安全，反应堆的主泵是不能关闭的，这会导致潜艇在不需要进行高速航行的时候出现不必要的噪声来源。而具备自然循环能力的反应堆，在一定功率值以下时，不需要开启主泵就能维持反应堆一回路的正常运转，保证反应堆安全的同时为潜艇输出所需要的推进和发电功率。 而核潜艇的日常巡航过程中，不会经常处于非常高的航速，如果反应堆具备自然循环能力，那么潜艇的大部分航行时间都可以处于一个较低的噪声状态。同为我国第二代核潜艇的093型核潜艇与094采用了一样的动力系统配置，曾有传言称，该型潜艇在国际海域巡航时表现出的静音能力远远超过西方国家之前的想象，这其中降噪贡献最大的应当就是该型艇的核反应堆具备自然循环能力。 当然，093和094的反应堆毕竟只是中国研发的第一种具备自然循环能力的船用反应堆，在设计和技术水平上与国际先进水平相比尚有不足，不开启主泵状态下的反应堆输出功率所能提供的航速相比美国的“海浪”和“弗吉尼亚”差距还很明显。不过值得期待的是，中国下一代核潜艇必将使用具备更强自然循环能力的核反应堆，甚至达到国际先进水平。
Google translation
Observer network military commentators said that with large-scale missile launch capability of China's second-generation nuclear submarine, it should be 094-type ballistic missile nuclear submarines, equipped with 12 waves -2 submarine missiles. Early China's first generation of nuclear submarines in the noise control level due to technical constraints, in fact, is very bad. A nuclear submarine in a voyage state can not use a conventional submarine to shut down the main engine noise reduction way to close the nuclear reactor, using a silent motor to drive. If the nuclear reactor does not have the natural circulation capacity, the main pump of the reactor can not be closed for safety. This will cause the submarine to generate unnecessary noise when it is not necessary to carry out high speed voyage. With the natural circulation capacity of the reactor, below a certain power value, do not need to open the main pump can maintain the normal operation of the reactor loop to ensure that the safety of the reactor at the same time for the submarine output required propulsion and power generation. The submarine's daily cruise process, not often at a very high speed, if the reactor with natural circulation capacity, then the submarine most of the voyage time can be in a low noise state. With the second generation of nuclear submarines in China's 093 nuclear submarines and 094 using the same power system configuration, there have been rumors that the submarine in the international sea cruise to show the mute ability far beyond the Western countries before the imagination, which Noise reduction should be the largest contribution to the type of nuclear reactor with natural circulation capacity. Of course, the reactors of 093 and 094 are only the first marine reactors with natural circulation capability developed by China. There is still no shortage of design and technical level compared with the international advanced level. Do not turn on the reactor output power in the main pump state. Can provide the speed compared to the United States "waves" and "Virginia" gap is still evident. But it is worth looking forward to is that China's next generation of nuclear submarines will use a stronger natural circulation capacity of nuclear reactors, and even reached the international advanced level.