055 Large Destroyer Thread II

[AndrewS]

Moving from mechanical drive to IEPS will lower the demand of total installed power because there is no need to keep a higher power reserve. If 4*28MW is for 055, its IEPS version may only need 20 to 25 MW. Example is the studied IEPS frigate in which the total installed power is reduced to 80%.

View attachment 169250

I don't know the designation of GT used by 076 but it is said to be rated at 21MW (normal operational). This GT was also mentioned by Ma Weiming as being able to serve as a module for large surface ship. So I think 4 of it would be a reasonable choice for 055, or 2*21+1*40MW. It is worth to mention that IEPS demands good power gradiance (number of smaller sized engine) instead of relying on fewer large engines, a lesson learnt hard way by Type 45.

I think the power gradience issue with the Type-45 is really about the diesel generators (4MW total) being undersized, in event of the gas turbines suffering a sudden failure, whether from the intercooler design flaw or from battle damage.

So the intercooler design flaw was fixed and they also increased the diesel generators from 4MW to 9MW for the Type-45.

---

Wouldn't you also have to account for the 6*5MW diesel generators from the Type-055?
So you end up with a total of 142MW.

So for an IEPS version, if they can reduce the installed power by 20%, then they only need 114MW.

They could potentially skip 28MW gas turbines and go directly to 40MW gas turbines for electricity generation. So you could end up with:

a) 6*5MW diesel and 2*40MW gas turbines, for a total of 110MW
b) 2*5MW diesel and 3*40MW gas turbines, for a total of 130MW
c) 4*5MW diesel and 3*40MW gas turbines, for a total of 140MW

These power gradients all look better than what exist in the Zumwalts.

And an IEPS Type-055A would have at least 10MW of diesel generators, which is more than the Zumwalt or Type-45, so it should be able to handle a sudden loss of a gas turbine. Most (all?) of the gas turbine electricity would be used for the electric motors driving propulsion, and they should be able to adjust electricity demand almost instantly

 

[qwerty3173]

a) 6*5MW diesel and 2*40MW gas turbines, for a total of 110MW
b) 2*5MW diesel and 3*40MW gas turbines, for a total of 130MW
c) 4*5MW diesel and 3*40MW gas turbines, for a total of 140MW

4*9MW diesel and 2*50MW GT gives 136MW which seems a more reasonable configuration. Too many separate engines is probably unnecessary for an IEPS configuration and also fewer engines means less room needed for smoke stacks.

 

[antiterror13]

Chinese IEPS is much more advanced as it is MVDC instead of AC on British type 45 and American Zumwalt.

In an AC system, you need to have stable frequency (60Hz or 50Hz). In an MVDC system, the power is "freed" from that cycle, allowing for a much more flexible and powerful setup

 

[AndrewS]

4*9MW diesel and 2*50MW GT gives 136MW which seems a more reasonable configuration. Too many separate engines is probably unnecessary for an IEPS configuration and also fewer engines means less room needed for smoke stacks.

Does a 9MW diesel generator for naval applications exist anywhere?

---

If we're speculating on the configuration of a Type-055A with IEPS, then it will probably be an evolution of the Type-076 IEPS.

So the Type-076 has 6*6MW diesels and 2*21MW GTs, which looks like a pretty conservative setup which overemphasises diesels.
If they were already confident in the setup, then it would be better to remove 3 diesels and add a single GT.

But it does allow them to test configurations comprising 2-6 diesels and/or 1-2 gas turbines. But the logical next step for IEPS would be on the Type-057 Frigate or Type-052D successor, rather than IEPS on the Type-055 straightaway.

---

A notional 5000tonne Type-057 Frigate configuration could be 2*6MW Diesel and 1*21MW GT.
We don't know much about a Type-052D successor, so I'm not going to speculate here.

Then eventually we would get a Type-055 IEPS, which might have 2*6MW Diesel and 3*33.5MW GTs? That assumes the CGT-30 GT has a generator version developed.

I suspect 40-50MW GT generators concentrate too much risk, plus there isn't enough demand to justify developing and supporting an entirely new class of larger naval GT generators.

Consider that the CGT-30 GT (33.5MW) fits in the same footprint as the CGT-25 (28MW).
So you could standardise on the CGT-30 GT (33.5MW) generator for all IEPS GT applications. Even Frigates are growing in tonnage enough that they can usefully use a 2*6MW Diesel and 1*33.5MW GT setup

And if you look at Air Forces, they are really keen on standardising on a single (gas turbine) engine for all their planes.

---

I also wouldn't get too caught up on the specifics of what IEPS setup is used on a particular ship.

The goal should be to create a single flexible/modular architecture for the entire fleet, which can accommodate different electrical generators depending on the requirements of each ship-class. Having said that, 2 diesel generators does seem to be the minimum in terms of sufficient reliability and resilience for a warship

 

[tphuang]

Moving from mechanical drive to IEPS will lower the demand of total installed power because there is no need to keep a higher power reserve. If 4*28MW is for 055, its IEPS version may only need 20 to 25 MW. Example is the studied IEPS frigate in which the total installed power is reduced to 80%.

View attachment 169250

I don't know the designation of GT used by 076 but it is said to be rated at 21MW (normal operational). This GT was also mentioned by Ma Weiming as being able to serve as a module for large surface ship. So I think 4 of it would be a reasonable choice for 055, or 2*21+1*40MW. It is worth to mention that IEPS demands good power gradiance (number of smaller sized engine) instead of relying on fewer large engines, a lesson learnt hard way by Type 45.

Yes it is pretty clear that if you go to IEPS, you don’t need as much total installed power to reach the same speed. It also allows you to efficiently share electrical power with on board demand.

I would think 4x CGT40 with IEPS would allow for quite a large and fast cruiser with significant power left for laser weapons and such.

 

[Andy1974]

Give the PLANs conservative nature I think the best bet is moving to non-IEPS 4x CGT-30M with everything else remaining the same, they may already have done this with the entire 2nd batch or just the last couple of ships.