09V/09VI (095/096) Nuclear Submarine Thread
- Thread starter Hendrik_2000
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I always found Mr. Wang has the killer aura in him when he speak, would like to see him face off with Pompeo
Can EM signals be detected and tracked underwater? If so, then would that negate its purpose?
I'd imagine that Magnetic Anomaly Detectors (MADs) are designed and built to do this but they aren't a silver bullet solution to locating and tracking subs because they need to be rather close to the submarine. How close only their navies know. But there are also plenty of ways to shield your EM signals and submarines have already used various methods to hide their acoustic and EM emissions for a long time.
Submarine technologies are very rarely discussed publicly and I'm totally clueless about them as well.
Can't.
The EM waves penetrate the sea for cms/meters.
Very low frequency waves can penetrate the sea for very deep, problem is in this case we talk about 100 Hz magnitude transmission.
Overall China's reactor tech is quite advanced. They have a strong part in the UK's Hinkley nuclear power plant under construction and has partnership with the Saudis.
But the problem may not be with the reactor but of the submarine itself, even if you have a potentially advanced reactor tech. The size and the draught of the 093 may limit its ability to house a natural circulation reactor --- one without or reduced coolant pumps --- as circulation is heavily dependent on gravity and temperature cycles to reduce or eliminate the use of mechanical pumps. Having a larger hull also means you can put more sound insulation and vibration dampeners across the hull. In fact, the 094 might be potentially quieter than the 093 due to its size.
If they want to make a quieter submarine, you have to start with a larger submarine. Size is one factor that helps, the rest boils down what you can do within that size.
Noise is also generated hydrodynamically --- the water flowing around the submarine --- so hydrodynamic design matters, locating sources of turbulences matters. That's why you see webbing of the bottom corner of the sub's sail, and smoothing out the top corner of the sub's sail, which is evident between the newer vs. older 093 and 094 designs. The change in the Yuan design is also for hydrodynamic refinement.
The third factor is propeller cavitation. The propeller must try not to produce bubbles, and there is a lot of secret sauce that pours into the hydrodynamic qualities into the propeller's blades. That's why propeller design and its manufacturing tolerances are so important, and its one of the most confidential areas of the submarine, hence it's always hidden from public view. Shrouding the propeller inside a duct may reduce noise and cavitation but at the cost of efficiency, which is why its used on more powerful nuclear submarines but not on less powerful nuclear submarines and SSks.
Other sources of noise include water passing through the sinkholes of the submarine. You know when fluid passes through a hole it can produce a note, like a flute. Designing the sink hole pattern is important. Noise released when the ballast is released. Noise when a torpedo door is opened and a torpedo is fired. More areas that are of concern that is not nuclear related. Then the interior of the submarine from padding and rubberizing the floors, walls and doors to absorb shock and sound.
So its a total approach to the submarine that must be attended.
Broccoli
Senior Member
My understanding from reading books is that quite large % of noise comes from pumps needed for reactors and one of the biggest advances on newer boats are those passive cooled reactors what dont need any pumps for water circulation.
1. Various people sometimes say 093 is size constrained but when measuring it on Google earth, and there are quite a few images available, there doesn't seem to be any width difference between 093 and LA class.
2. Some years ago there were articles explicitly mentioning natural circulation used in new sub, which at the time people concluded it was 093.
2. Some years ago there were articles explicitly mentioning natural circulation used in new sub, which at the time people concluded it was 093.