055 DDG Large Destroyer Thread

[Iron Man]

That might be true for the current iteration of 055s which don't yet have IEP but it won't be true for the followup sub-class, 055A. Four QC280s will provide the IEP vessel with ~100MW of power, plenty to play with.

Just to put the potential electrical power of the 055A into perspective, the Royal Navy's QE class carriers have around 110MW total electrical power at their disposal.

the 112MW figure is the one being called excessive, because in a non IEPS configuration, that 112MW is the shaft power driving the propellers which Zumwalt certainly does not have.

In the 2nd batch of 055 (055A), the "excess" of that 112MW will be added into the consumption of EM guns and other electronics, which becomes not excessive. So is the future proof and nicely planned.

I think it is far from definite that a 055A with IEP will keep the 055's current arrangement of 4 28MW GTs + 6 3-6MW GTs. That's a total of 130-148MW power. The 055 cannot tap into all of that power obviously, only the GT generator-derived portion (18-36MW). Other power-hungry ships like the Flight III ABs have an installed power of 12MW. The Type 45 has a total installed power of 47MW including what is needed for propulsion. A 055A that is able to utilize power from the QC-280s may only need 2 of them, and maybe only 3 of the 6 3-6MW GT generators for a total installed power of 65-74MW.

 

[Blitzo]

I think it is far from definite that a 055A with IEP will keep the 055's current arrangement of 4 28MW GTs + 6 3-6MW GTs. That's a total of 130-148MW power. The 055 cannot tap into all of that power obviously, only the GT generator-derived portion (18-36MW). Other power-hungry ships like the Flight III ABs have an installed power of 12MW. The Type 45 has a total installed power of 47MW including what is needed for propulsion. A 055A that is able to utilize power from the QC-280s may only need 2 of them, and maybe only 3 of the 6 3-6MW GT generators for a total installed power of 65-74MW.

I'm wondering whether an 055A with IEPS would just ditch the non-QC-280 GT generators and use the internal volume for something else. I suppose the good thing about IEPS is they will be able to pick and choose which number of GTs of each type is able to fit their power demands while also taking up the least space and weight.

 

[Iron Man]

I'm wondering whether an 055A with IEPS would just ditch the non-QC-280 GT generators and use the internal volume for something else. I suppose the good thing about IEPS is they will be able to pick and choose which number of GTs of each type is able to fit their power demands while also taking up the least space and weight.

I think it is more likely that it will be a mix of the larger and the smaller GTs. The QC-280 like every other GT is most fuel-efficient at near maximum output, which means any output less than that is a waste of fuel (relatively speaking), while a smaller 3-6MW GT running at near full output is much more likely to occur in day-to-day ship operations. 3 of these smaller GTs would allow for a much smoother and fuel-efficient ramp-up in power needs, with one or both QC-280s turned on at moderate to high speeds and/or when the railgun needs to be fired.

 

[hkbc]

I'm wondering whether an 055A with IEPS would just ditch the non-QC-280 GT generators and use the internal volume for something else. I suppose the good thing about IEPS is they will be able to pick and choose which number of GTs of each type is able to fit their power demands while also taking up the least space and weight.

The QC-280 on the 055 aren't Gensets they're prime movers attached to the shafts, shouldn't mix power output from drive with electrical power generated by a genset. The output of a QC-280 as a genset is unknown (not even sure if a QC-280 genset exists!).

For the P portion of an IEP electric motors are needed these have different characteristics and power delivery (mechanical) than GTs, the better torque characteristics of electric motors means they move better than their nominal peak power suggests

Currently the most sophisticated military IEP is probably in the QE class carriers with

- 2 x Rolls Royce MT30 (36MW) Gas Turbines with 35MW alternators [70.0MW combined]
- 2 x Wartsila 16V38 (11.6MW) Diesel engines with 11.2MW alternators [22.4MW combined]
- 2 x Wärtsilä 12V38 (8.7MW) Diesel engines with 8.4MW alternators [16.8MW combined]

driving 4 x 20MW AIM motors (you'll notice that 3.4 MW of mechanical power that is lost is the electrical generation process)

leaving ~29MW available for the radars lights lifts etc...

Assuming the Chinese have similarly capable alternators then 4 x QC280 should deliver a similar amount of electrical power and a vessel even the size of the 055 shouldn't need anymore (electric) drive power than 75-80MW to move it at full speed (for comparison Zumwalt has 78MW electric motors) I guess the excess gives the 30MW or so necessary to power the EM Gun without affecting the rest of the ship's systems, although as a military system a bit of extra margin is usually called for.

As for space GT's need lots of airflow (therefore trunking) so you can't just drop them willy nilly anywhere (the QE use diesels as well as GTs because it's no fun trying to get trunking through a hangar, the GT's are placed under each island, where as the diesels are placed else where for better survivability). However, assuming the electric motors can go where the gearboxes would be there's no loss of space if they planned space for the alternators in the engine rooms already, if they did, that would indeed be a master stroke of planning!

 

[Iron Man]

The QC-280 on the 055 aren't Gensets they're prime movers attached to the shafts, shouldn't mix power output from drive with electrical power generated by a genset. The output of a QC-280 as a genset is unknown (not even sure if a QC-280 genset exists!).

I'm sure Bltizo was talking about QC-280 output in the setting of it being attached to the electrical grid rather than a transmission gearbox. In any case I have absolutely no doubt that if IEP is in the works for the 055 class, a QC-280 genset already does or will exist fairly soon that outputs power about the same as the GT itself.

Assuming the Chinese have similarly capable alternators then 4 x QC280 should deliver a similar amount of electrical power and a vessel even the size of the 055 shouldn't need anymore (electric) drive power than 75-80MW to move it at full speed (for comparison Zumwalt has 78MW electric motors) I guess the excess gives the 30MW or so necessary to power the EM Gun without affecting the rest of the ship's systems, although as a military system a bit of extra margin is usually called for.

I suspect the power output of the Zumwalt is at least somewhat future-proofed already, so that 78MW should probably be seen as well in excess of what the Zumwalt currently needs, which means a 055A power output of 65-74MW would also be well in excess of what the 055 currently needs, since we are talking about a 12-13kt 055/A in comparison to a 14.8kt Zumwalt. By way of comparison the 65kt QE carrier outputs a maximum of 110MW.

As for space GT's need lots of airflow (therefore trunking) so you can't just drop them willy nilly anywhere (the QE use diesels as well as GTs because it's no fun trying to get trunking through a hangar, the GT's are placed under each island, where as the diesels are placed else where for better survivability). However, assuming the electric motors can go where the gearboxes would be there's no loss of space if they planned space for the alternators in the engine rooms already, if they did, that would indeed be a master stroke of planning!

GTs on the 055 actually have lots of wiggle room in terms of placement, especially if there are going to be only two of them and if the power/propulsion system is IEP, enabling the induction motors to be installed in spaces a traditional transmission gearbox cannot be. The continuous topside stack housing also allows the GTs to be placed anywhere along the structure.

 

[Blitzo]

I'm sure Bltizo was talking about QC-280 output in the setting of it being attached to the electrical grid rather than a transmission gearbox. In any case I have absolutely no doubt that if IEP is in the works for the 055 class, a QC-280 genset already does or will exist fairly soon that outputs power about the same as the GT itself.

Indeed I was.

The QC-280 on the 055 aren't Gensets they're prime movers attached to the shafts, shouldn't mix power output from drive with electrical power generated by a genset. The output of a QC-280 as a genset is unknown (not even sure if a QC-280 genset exists!).

-------------

As for space GT's need lots of airflow (therefore trunking) so you can't just drop them willy nilly anywhere (the QE use diesels as well as GTs because it's no fun trying to get trunking through a hangar, the GT's are placed under each island, where as the diesels are placed else where for better survivability). However, assuming the electric motors can go where the gearboxes would be there's no loss of space if they planned space for the alternators in the engine rooms already, if they did, that would indeed be a master stroke of planning!

Depends on whether 055 was planned to have a future variant with IEPS to begin with. Tbh I would be surprised if the current hull design was not intended to have that kind of growth capacity for a future variant.

 

[Deino]

Was this already posted?? PLN Type 055 DDG no. 3 + 4 + 2 Type 052D at Dalian - 20171221

 

[Rachmaninov]

Was this already posted?? PLN Type 055 DDG no. 3 + 4 + 2 Type 052D at Dalian - 20171221

View attachment 45243

Yes it was.

end december 2017

 

[Deino]

Ohh ... then thanks for the reminder.

 

[hkbc]

I'm sure Bltizo was talking about QC-280 output in the setting of it being attached to the electrical grid rather than a transmission gearbox. In any case I have absolutely no doubt that if IEP is in the works for the 055 class, a QC-280 genset already does or will exist fairly soon that outputs power about the same as the GT itself.


I suspect the power output of the Zumwalt is at least somewhat future-proofed already, so that 78MW should probably be seen as well in excess of what the Zumwalt currently needs, which means a 055A power output of 65-74MW would also be well in excess of what the 055 currently needs, since we are talking about a 12-13kt 055/A in comparison to a 14.8kt Zumwalt. By way of comparison the 65kt QE carrier outputs a maximum of 110MW.


GTs on the 055 actually have lots of wiggle room in terms of placement, especially if there are going to be only two of them and if the power/propulsion system is IEP, enabling the induction motors to be installed in spaces a traditional transmission gearbox cannot be. The continuous topside stack housing also allows the GTs to be placed anywhere along the structure.

Get where you are coming from

The 78MW for the Zumwalt is what the drive motors driving the shafts can produce, the total output from the gensets is more, given its non-standard hull form it's probably all needed to get to flank. The QE "only" has 80MW driving it's props because the largest induction motors they had were 20MW ones and because of penny pinching it only has 2 shafts (can only shove so much power down a shaft) they used a bulbous bow to get it's top speed to a nominal 26kt adequate but would need an extra shaft to get past 30kt.

Hull form rather than displacement plays a big part in a ships speed a 40+K ton Nelson class battleship got tp 23kt with just 34MW! but I digress, Don't think they'll get away with just 2 QC-280s (56MW minus generation and transmission losses means robbing a 10MW from elsewhere) so probably need at least 3 (easily doable since they aren't hooked up to a shaft) but that really depends on what size electric motors they have, no point generating excess that can't be consumed, conversely no point not fitting enough. They could swap out a couple of the QC-280s for diesels which are more flexible (don't have to run them a full tilt to be efficient) but for maintenance probably easier to stick with all GTs.