January 4, 2018

Australian Future Sub's Diesel Generator Requirements - PART TWO

This article follows PART ONE, published January 3, 2018.

The Australia’s Future Submarine (future sub) is very large for an SSK. So powerful diesel-generators in the 2MW class are desirable. This should minimise the number of diesel-generators and keep the length and displacement of the submarine within efficient limits.


The diesel-generator requirements of  the future sub remain unknown due to understandable lack of:

-  published figures on the future sub's actual snort cruising speed – between 9 and 14 knots
-  a final decision on whether the future sub will use existing lead-acid batteries or lithium-ion
   batteries (which can benefit from higher charging rates of more powerful diesel-generators)
-  whether 4, 5 or 6 diesels fit best in the future sub (eg. can diesel-generators be mounted 2 sets of 3
   horizontally across? or 2 sets of 3 fitting into the sub’s circular diameter?)
-  whether the diesels will have single or twin turbochargers or superchargers or the latest fuel 
   injection system, and
-  how pressure considerations are taken into account to minimise seawater ingestion into fuel
   tanks

This Naval Group Barracuda-Suffren class SSN cutaway (with K15 reactor) unfortunately does not resolve how 4 to 6 diesel-generators could be arranged in Australia's Future Submarine (Cutaway from Naval Group via navyrecognition via Submarine Matters)
---

Power requirements are therefore vague, but the future sub will require around 6 to 8MWe of output - noting its 4,500 tonne (surfaced) displacement and also its high hotel load (serving the (usually nuclear submarine) AN/BYG-1 combat system). 

Unusually powerful diesels are risky if they have not been tried and tested in submarines for years before Australia accepts them. The Collins at 3,100 tonnes (surfaced) uses 3 Garden Island-Hedemora diesels with a total output of 5.25MW x 0.8 = 4.2MWe. The Hedemoras needed to be unusually high powered for their time, unfortunately meaning they were untried in submarines, unreliable, restricted use and disliked by RAN submariners. 

From a December 2017 comment on diesel-generator choices for the future sub - ideally the diesels should be around 2MW: 

Approaching 2MW output is the KAWASAKI 12V/25/25SBs at 1.7MW. Two KAWASAKI ((Totalling 3.4MW output) are used in Japan’s (2,900 tonne (surfaced)) large Soryu SSK. So if 4 x 1.7MW (Kawasakis) are used = Total 6.8MW. 6.8 x 0.8 (power factor) = 5,44MWe. Five Kawasakis may be needed to exceed 6MWe, so 5 x 1.7 x 0.8 = 6.8MWe. It is highly unlikely France and/or Australia would select a Japanese diesel.

If the KAWASAKI option is discarded Australia might require 6 diesels of lower power output, of part-known submarine reliability, even if this increases the dimensions of the submarine. 

Both MAN12PA4V200SMDS [1] at 1.33MW and MTU12V4000U83 [2] at 1.3MW appear to have the same performance. Whether they have been sufficiently tried and tested on submarines may still be an open question. Although the piston speed of the engine MAN diesel (at 9.1m/s) is lower than that of MTU (11.4m/s). Anonymous advises lower piston speed tends to reduce sound producing vibration. 

Calculating 6 x MAN12PA4200SMDSs = 6 x 1.33 x 0.8 = 6.4MWe.

OR

6 x MTU12V4000U83s = 6 x 1.3 x 0.8 = 6.24MWe.

[1] MAN 12 PA4 V 200 SMDS: Bore 200 mm, Stroke 210 mm, Mechanical output 1.33MW at 1300 rpm (=Piston speed 9.1m/s) , Generator output 1.064MW
(see http://www.marine.man.eu/docs/default-source/shopwaredocuments/pa4-sm-smdsfba3ca1740b144429518d4e002fd7d6f.pdf?sfvrsn=3 )

[2] MTU 12V4000U83: Bore 170 mm, Stroke 190 mm, Mechanical output 1.3MW at 1800 rpm (=Piston speed 11.4m/s), Generator output 1.040MW
( see http://www.tognum.com/fileadmin/fm-dam/tognum/press/2011/MTU_Submarine_Charging_Unit_12V_4000.pdf )

Naval Group and the Australian Government might decide to publicise what they have chosen to solve these diesel-generator output issues in the next 3 or 4 years.

Anonymous and Pete 

15 comments:

Anonymous said...

Hi Pete

There is an opinion that Japan should export parts of submarine equipment for future weapon trade. Though KAWASAKI 12V25/25SB, one of the most powerful diesels for submarine, seems to be an attractive candidate for weapon trade, some issues should be fixed to export it. I think that turbocharger and supercharger system, key technology of 12V25/25SB, belongs to MAN’ patent. Licensing of MAN’s patent as well as approval by Japan National Security Committee will be needed for export. Information on status of MAN’s patent and idea of KHI/Japanese government as well as Naval Group should be collected.

12V25/25SB is going to be modified for LIBs-Soryu (27SS and 28SS) and again to be modified for post- Soryu (29SS). I expect or hope that increase in power and adoption of Common Rail Diesel system are achieved in these modifications.


Regards

Josh said...

@Pete

I thought the Shortfin was explicitly stated to have four diesel engines? Though I've never heard power or model specified.

Cheers,
Josh

Tri-ring said...

Doubt Japan will agree in just exporting engines which has no added value for Japan.
Australia can fiddle with their thumbs as DCNS ponders on their head on the engine issue till the cow comes home.

Peter Coates said...

Hi Anonymous [at 5/1/18 1:19 AM]

With the combination of KHI/Japanese Government and MAN technology (that produces the powerful KAWASAKI 12V25/25SB) that you describe:

perhaps Naval Group could work through mainly European owned MAN Diesel https://en.wikipedia.org/wiki/MAN_Diesel to negotiate rights to the Japanese portion of the KAWASAKI 12V25/25SB.

When the KAWASAKI 12V25/25SB is made even more powerful to handle LIBs and post Soryu class needs it will more closely approach the 2MW power level needed for Australia's future sub. Perhaps MAN can produce this KAWASAKI 2MW engine under licence?

This website http://global.kawasaki.com/en/corp/profile/division/machinery/history.html is interesting where it records that in "1987 [Kawasaki] Started the production of MAN B&W type marine diesel engine at the Hanshin Diesel Works, Ltd. under KHI's license."

Regards

Pete

Peter Coates said...

Happy New Year Josh

Yes Hans J. Ohff commented on Selection of Naval Group Day (April 26, 2016) https://theconversation.com/why-the-french-submarine-won-the-bid-to-replace-the-collins-class-58223 :
"The Shortfin Barracuda will be equipped with four diesel alternators to generate electricity, a >7 megawatt permanent magnet motor and ample battery storage."

It will be a daunting technical task to develop 4 high power diesels with the total output of 8.75MW that is sufficient to generate 7MWe output. Noting 8.75M x 0.8 = 7MWe.

So choice of a proven Pacific engine may be by way of a very powerful mainly Kawasaki and MAN evolution of the already proven on submarines KAWASAKI 12V25/25SB (see above).

But the conservative nature of a European designer and the RAN may again select a fundamentally smaller European submarine engine instead of the proven larger Japanese engine built for Pacific conditions. Choice of a smaller European diesel may overwork a fundamentally Euro-diesel as occurred with the Collins unreliable Garden Island-Hedemora.

The diesels and too much salty Pacific (saltier than the Baltic) seawater (in the fuel tanks) being the main continuing weaknesses of the Collins.

Regards

Pete

Tri-ring said...

This website http://global.kawasaki.com/en/corp/profile/division/machinery/history.html is interesting where it records that in "1987 [Kawasaki] Started the production of MAN B&W type marine diesel engine at the Hanshin Diesel Works, Ltd. under KHI's license."

I believe they are talking about surface ship engines like the MAN-B&W-10L80MC Mk5 (46,700PS) marine diesel engine of 1993 and, Kawasaki-MAN B&W 12K98ME of 2006.
It does not mention anywhere about the 12V25/25SB.
If you do some research the Harushio class are the first to utilize the 12V25/25 series in the late 80's.Furthermore the 12V25/25 series is an extension of the V8V24/30mAMTL diesel engine powering the Yushio class of the mid 70's.

Anonymous said...

Hi Pete

As SEA 1000 submarine proposed by Japan is based on Soryu [1], archetcture of Soryu may provide a hint on architecture of SEA 1000 J-sub. Reported features of SEA1000 J-sub are non AIP, improvement of endurance, equipment of LIBs, and 6-8m extended length (total length 90-92m). Two huge LOX tanks (section (10) in [1]) and AIP [section (9)] in Soryu is used for improvement of endurance and increased number of LIBs in SEA 1000 J-sub, and enough space is offered for crews within the length of Soryu (84m). Then, what is the extend length (+6m) of SEA 1000 J-sub for? I believe new compartment for two diesel generators is introduced between 4th and 5th compartments to improve indiscretion ratio in SEA 1000 SEA J-sub.

Shortfin equipped with smaller MAN or MTU than KAWASAKI is 6m longer than SEA 1000 J-sub.What does it mean? As Scorpenes for Chile equip four diesel generators [2], larger Shortfin equips more than four generators. Arrangement of 4diesels, 4 diesels+ AIP or 6 diesels may be possible for Shortfin.

[1] http://gentleseas.blogspot.jp/2015/10/diagram-inside-soryu-submarine.html
(Diagram – Inside the Soryu Submarine)

[2] http://www.revistanaval.com/archivo-2001-2003/ohiggins.htm
Submarino General O'Higgins (SS-23)
Diesel-electric propulsion: 1 electric drive motor and 4 diesel engines. The latter type Izar-MTU 12V396 SE 84, 632 Kw at 1700 rpm, have been supplied by Izar Propulsion and Energy Motors.

Regards

Josh said...

@Pete:

I haven't waded through all the numbers, but broadly speaking the Japanese engines seem like the way to go, though I don't see that happening for licensing and political reasons. But IMO it again points to the fact that the Shortfin was the wrong choice, vice the company that already produced large ocean going submarines with reliable diesels. My opinion.

Cheers,
Josh

Anonymous said...

MHalblaub said...

Dear Pete

The part about the MTU engine is not explained enough. The MTU 4000 series has more to offer than just the 12V. The power range goes from 760 kW up to 4300 kW (20V 4000 M93L). The engine with 16 cylinders is rated at 3440 kW (16V 4000 M93L). MTU just offered the 12V for „normal“ sized Diesel submarines but I can imagine that it is not a great effort to submerse more powerful engines.

Size of 4000 series
(Height x Width x Length) mm without gearbox

12 V: 2185 x 1850 x 2870
16 V: 2185 x 1850 x 3510
20 V: 2240 x 1470 x 4040

From my professional point of view piston speed is rather irrelevant for structure born noise. The problem is related to accelerated mass. There is a reason why engines have a certain count of cylinders. Higher frequencies are easier to damp than lower ones. 2100 rounds per minute is 35 Hz.

Regards and a happy new year!

MHalblaub

Peter Coates said...

Hi MHalblaub, Anonymous and Josh

This subject is getting more interesting - especially exploring 2+MW submarine engines that are already in use or possible future options.

Because of the essential requirement that a submarine diesel can rapidly stop, start and even reverse this increases the value of Already In Use and makes constant running diesels potentially risky. Several high powered train/railway diesels have been unsuccessfully adapted to Victoria/Upholder [1] and Collins [2] use in the past/present.

[1] https://en.wikipedia.org/wiki/Paxman_Valenta

[2] https://en.wikipedia.org/wiki/Hedemora_Diesel#Locomotives_with_Hedemora_engines

I'll write a "Australian Future Sub's Diesel Generator Requirements - PART THREE" article next week.

Regards

Pete

Anonymous said...

Hi Pete

As simple increase in cylinder number sometimes results in awful vibration as shown in Hedemora V18B14SUB [1], careful consideration is needed in adoption of submarine diesel. Submarine diesel is used under severe conditions such as stop and maximum rotaion operation without warm-up, and is quite different from other marine diesel.

MTU adopts “regulated two-stage turbocharging” system consisted of high and low pressure turbochargers. In picure of [2], we can find two high pressure turbochargers.

In the case Scorpene, Royal Malaysian Navy adopts two MAN 12 PA4 200SMDSs for KD Tunku Abdul Rahman [3], while Chile Navy adopts four MTU 12V396 SE84s for O´Higgins [4].

[1] https://www.rina.org.uk/iqs/dbitemid.1665/rp.2/sfa.view/Section_News1.html
(Technical Meeting -- 3 February 2016)
“Hedemora had demonstrated the V12B configured for snorting, and promised that the V18B would work as well giving 1.4 MWe. However, they had never actually built a turbocharged V18B14SUB, but had built lots of V18B engines for industrial power and marine generator sets, and had tested a V12B against submarine-type conditions. They had built a number of V12A (smaller bore) submarine engines for the Royal Swedish Navy, the latest examples being turbocharged. Therefore the V18B14SUB was accepted as an off-the-shelf design, which it really wasn’t. But then, nothing else seems to have met the specification either. Now we have all 19 of the Hedemora V18B14SUB engines in the world! The V indicates the vee configuration, the 18 is the number of cylinders, the B is the larger bore (210×210 mm), the 14 is the speed (1400 rpm), and the SUB category is the monolithic engine (not bedplate mounted) for submarines.”

[2] http://www.australiandefence.com.au/defence-suppliers-news/penske-debuts-next-generation-diesels-for-submarines
According to MTU, features of regulated two-stage turbocharging are as follow. In the case of regulated two-stage turbocharging, two turbochargers are connected in series. In the system configuration employed by MTU, the exhaust flow from the cylinders is split so that part of it passes through the high-pressure (HP) turbine and the rest is diverted through abypass by a controllable wastegate valve. The entire mass flow then flows through the low-pressure turbine (LP)

[3] https://en.wikipedia.org/wiki/KD_Tunku_Abdul_Rahman

[4] http://www.revistanaval.com/archivo-2001-2003/ohiggins.htm

Regards

Anonymous said...

Hi Pete

Mechanical output of 12V/25/25SB is said to be 3100ps (=2280kW), and its electrical output is 1824kW (=2280kWx0.8). Specifaction of diesel generators for Soryu MKII (LIBs-Soryu, 27SS, 28SS) is going to be reviewed.

As charging capacity of LABs is lower than power generation capacity of generator, even low power generator can satisfy charging capacity of LABs. But, charging capacity of LIBs is much higher than LABs, and high power generator is needed.
Output of modified 12V/25/25SB for Soryu MKII may increase. In case of automobile engine, enlargement of turbo/supercharger, increased capacity of engine cylinder or improvement of intake/exhaust is conducted to increase power.

Regards

Peter Coates said...

Thanks Anonymous [8/1/18 12:41 PM]

I'll include your favourable 12V/25/25SB advice in "Australian Future Sub's Diesel Generator Requirements - PART THREE" on Weds or Thurs this week.

So far I think Naval Group should work through the MAN grouping to work with Kawasaki to licence a 12V/25/25SB development for the Aus Future sub. This is noting MAN and Kawasaki seem already closely associated on submarine diesel technology.

I first need to complete the final Donor report on Tues or Weds.

Regards

Pete

Anonymous said...

Hi Pete

Though big diesel for ship needs rather long warm up period, diesel for submarine reaches maximam speed without warm up. This results in large heat gradient of diesel, causing large thermal shock, stress or fatigue. If thermal shock, stress or fatigue exceeds a certain level of strength of material, material experiences irreversible damage such as cracks or fracture.

In design of submarine diesel, temporal thermal stress distribution is calculated to decide the domain exposed to high thermal shock or stress, and I believe that expensive heat resistant steel or alloy is used in that domain. Various treatment and ingenuity of the design will be conducted and the result will be proved by time consuming experiments. As a result, the development of diesel is very tough and expensive.

I also introduce interesting video of diesel production by Navantia under assistance of MTU. ( https://www.youtube.com/watch?v=q8pMJM3LAjA)

Regards

Peter Coates said...

Hi Anonymous [at 10/1/18 1:26 AM]

Thanks for your comment.

I'll include it in "Australian Future Sub's Diesel Generator Requirements - PART THREE" tomorrow (Thursday).

Regards

Pete