Rumoured "mini-nuke/diesel" Submarine SSK-N(?) thread

[Staedler]

I'm not sure why Yuan is always transiting at PD if depth has such insignificant effect on power requirements then?

Yuan class right now has 320kW for its stirling engine. I'm basing hotel load on that. It's possible that for some smaller subs like 212, 90kW is enough. But boats with more sensors and computation power would require more. How much power does latest Intel CPU or Nvidia GPU consume? And atmospheric control (if they do chose to install it), would require quite a bit of power.

Would presume that's more related to reducing mechanical stress than anything electrical; pressure is the main thing that changes after all.

Aren't anechoic tiles made from polymer? So they would all suffer from creep and plastic deformation. The hull would be fine, but the tiles would suffer accelerated aging proportional to duration and depth. So transit below PD may incur additional maintenance costs that are not considered to be sufficiently impactful to the mission to justify.

Please accept my ignorance, I googled and found what "hotel load" means in electrical engineering, but what is "PD"? Is it Port of Destination?

Should be Periscope Depth

 

[BoraTas]

I'm not sure why Yuan is always transiting at PD if depth has such insignificant effect on power requirements then?

Yuan class right now has 320kW for its stirling engine. I'm basing hotel load on that. It's possible that for some smaller subs like 212, 90kW is enough. But boats with more sensors and computation power would require more. How much power does latest Intel CPU or Nvidia GPU consume? And atmospheric control (if they do chose to install it), would require quite a bit of power.

As far as I read from submariners on the internet, SSK commanders don't like their battery below some threshold during transits and long snorkeling periods. So snorkeling briefly every 12-24 hours is a common practice. AIP fuel isn't used during transits because it isn't replenishable and is relatively limited unlike battery charge or diesel fuel. If they transited deep, they would have to expose the sub to a pressure cycle twice a day. That might be acceptable in wartime but is probably not desired in peacetime. The Yuan's 320 kW AIP system would be for covering the hotel load plus propulsion load at 6-7 knots, like other AIP equipped subs.

 

[tphuang]

As far as I read from submariners on the internet, SSK commanders don't like their battery below some threshold during transits and long snorkeling periods. So snorkeling briefly every 12-24 hours is a common practice. AIP fuel isn't used during transits because it isn't replenishable and is relatively limited unlike battery charge or diesel fuel. If they transited deep, they would have to expose the sub to a pressure cycle twice a day. That might be acceptable in wartime but is probably not desired in peacetime. The Yuan's 320 kW AIP system would be for covering the hotel load plus propulsion load at 6-7 knots, like other AIP equipped subs.

I've been told 320kW AIP for Yuan is not enough to go that fast. I think you cannot compare the power demand of a large sub like Yuan with something like 212 or Gotland.

AIP fuel - are you referring to cryogenic oxygen? That's definitely not replenishable. But snorkeling is also needed just for ventilation and such. That's different from surfacing to charge

 

[BoraTas]

I've been told 320kW AIP for Yuan is not enough to go that fast. I think you cannot compare the power demand of a large sub like Yuan with something like 212 or Gotland.

Yeah. Likely. The Type 214 achieves 6 knots with 240 kW. The Yuan has almost double the displacement so its power requirement for the same speed should be like 60% higher. It also has a 33% bigger crew.

AIP fuel - are you referring to cryogenic oxygen? That's definitely not replenishable. But snorkeling is also needed just for ventilation and such. That's different from surfacing to charge

Yes. Also hydrogen for fuel cell equipped subs. As far as I understand, fuel cells can work in reverse too but the sub wouldn't have much time to regenerate propellants from waste water. I wonder how AIP subs handle CO2. They carry tons of oxygen. If they have something to get rid of the CO2, in theory they can get away with snorkeling for long periods.

 

[tphuang]

alright, so i looked over the original 320 KW Stirling engine article with @BoraTas

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It seems like there is a good chance they have a larger Stirling engine here designed for nuclear sub

The success of the prototype is a milestone and a major breakthrough China has made in key technologies and craftsmanship in developing such kind of engines and laid down the foundations for its development of megawatt-class Stirling engines in the future, the CSSC said.

The Stirling engine is a closed-cycle reciprocating power machine that takes heat supply from external sources, the press release explained, noting that the engine can be combined with any kind of heat source, either conventional or nuclear energy, in many configurations.

A megawatt-class Stirling engine is tightly structured, has a simple system and can be started quickly and configured in modules. These will be significant advantages of the Stirling engine, the CSSC announced.

When used together with a sodium-cooled fast reactor, the Stirling engine can eliminate the risk of sodium-water reaction making it also a very safe choice.

It would make sense to me if the 320 kW stirling engine is for 039C or another diesel electric sub
And that they have a 1-2 MWe Stirling engine for mini nuke. Seems to me that set up for reactor -> stirling engine -> eDrive -> eMotor -> propeller can be quite efficient and would be easier to mount than the idea of 4 to 6 Stirlings

I'm more inclined to believe in Stirling theory now, although just 1 large stirling engine that can easily be mounted vs multiple. And I think if they can get 2MWe, it will be able to do pretty much anything you want it to do.

And if this thought experiment showed anything, it's that IEPS is a much superior tech than your traditional mechanical propulsion. I think even @Blitzo previously mentioned 095 using IEPS, but I may have remembered incorrectly. If they can do IEPS on a larger scale, there is no reason to have reduction gears, coolant pumps, transformers, shaft. You just have the electric drive getting power from battery and/or steam turbine and then sending that to electric motor to drive the propeller and the auxiliary power for running the submarine. There is no reason China cannot build a 40MWe electric motor to power a submarine.

 

[Blitzo]

And if this thought experiment showed anything, it's that IEPS is a much superior tech than your traditional mechanical propulsion. I think even @Blitzo previously mentioned 095 using IEPS, but I may have remembered incorrectly. If they can do IEPS on a larger scale, there is no reason to have reduction gears, coolant pumps, transformers, shaft. You just have the electric drive getting power from battery and/or steam turbine and then sending that to electric motor to drive the propeller and the auxiliary power for running the submarine. There is no reason China cannot build a 40MWe electric motor to power a submarine.

Just re this seeing as it's brought up, I consider it a possibility that IEPS (or rather, turboelectric) could be used on 09V mostly because Ma mentioned it as something he declared would be used on the PLAN's next generation nuclear submarines.
Whether it will have it or not, who knows.

 

[aahyan]

https://twitter.com/i/web/status/1776903165671010309

https://twitter.com/i/web/status/1777181784339337560

https://twitter.com/i/web/status/1777288839481934237

 

[nemo]

I am questioning the veracity of anything that refers to next conventional submarine as type 041 -- it should be 0310 or 03-10, or 03X(roman numeral X). The first two digits are category code while the remaining digit(s) are type code within the category. Since the is a 039, the next one would be 0310.

 

[lcloo]

I am questioning the veracity of anything that refers to next conventional submarine as type 041 -- it should be 0310 or 03-10, or 03X(roman numeral X). The first two digits are category code while the remaining digit(s) are type code within the category. Since the is a 039, the next one would be 0310.

It is a flaw thinking of many people who tend to think that since there is already a type 039, then the next few new subs should be 040, 041, 042 etc., but this doesn't work in China. Example type 032 the latest testbed appeared many years later than type 035 and 039. They don't follow in sequencing order.

Also, since this is a nuclear powered submarine, it might not be under the 03-X class. There is a possibility of it be given a 09-XX designation, with the double digit XX to indicate its small size.

All current nucleared powered submarines in PLAN are given type 09-X designations.

Just my 2 cent, since there is total blank in info in this regard.

 

[para80]

Not to mention the fact that 039 includes two completely different submarines, the Song and Yuan types. It could also be 039D for all we know but again a lot depends on its inherent characteristics and how it fits into the overall designation scheme in that regard.