January 18, 2018

Japanese Soryu Higher Power Snorkel (Intake and Exhaust) Study


"wispywood2344" has drawn and labelled this very useful diagram of the Japan's top of the line Soryu class submarine.  The diagram (minus the Stirling AIP) could represent the Japanese entrant "SEA-1000 Japanese submarine (SEA-J)” in the Australia’s Future Submarine competition (which France won in April 2016). larger version of the diagram is at http://blog.livedoor.jp/wispywood2344/others/Soryu_cutaway.svg
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Anonymous has kindly provided information for the following. One of the key factors in considering Soryu propulsive power (see January 16, 2018 article) comes through taking account of the efficiency of the snorkel (diesel intake and exhaust) system. If resistance against snorkel intake and exhaust is too high, the diesel generation system does not function well, resulting in poor output. 

Though the effectiveness of intake and exhaust system has been proven for Japanese submarines equipped with generators of around 4MW (total), the effectiveness of intake and exhaust has not been published for 8MW generators (the power required by Australian Future Submarines).

In this current article there is some discussion of the Japanese entrant "SEA-J" (diagram above) a Soryu enlarged for Australian conditions.

LARGER SEA-J

SEA-J highly likely omitted the Stirling AIP  (including LOx tanks, sections (9) and (10), 4th compartment) and was lengthened by 6m (from current 84m to 90m). This provided for:
-  extra diesel fuel (to increase range from the current Soryu Mark I's limited 6,100nm 
   range to the 10,000-12,000nm Australia required 
-  extra batteries (for increased fully submerged range on battery) and
-  larger bunks for the on average taller crew. The bunks are already individual for 65 crew
   (ie. no uncomfortable "hot bunking").  

Omitting the AIP (especially the large, weight shifting, LOx tank, of diminishing utility on Australia's long range missions) is easily understood. But the 6m increase in length is less understandable. SEA-J's extra length may be needed to handle an extra two diesel engines (four in all for the 8MW total power) instead of just two diesels in the existing Soryu Mark I

MORE POWERFUL SNORKEL SYSTEM

Rearrangements in SEA-J may be new sections 5, 6 and 7 to accommodate the larger, more powerful, diesel driven snorkel sytem. Such a faster working snorkel system would be required for the extra pressure and faster operation of four diesels (totaling 8MW) in SEA-J.

A larger, more powerful snorkel system may also be required in the Soryu Mark II (see Table, for 27SS, laid down in 2015) which may be launced in 2018. Mark II will have more powerful diesels to more quickly charge and technically exploit the new Lithium-ion batteries (LIBs) to be introduced in Mark II

Faster charging on Mark II will improve its indiscretion ratio (IR). Indiscretion being a submarine's fully surfaced or shallow submerged danger period, when it is snorting. SEA-J could have also benefitted from fast charge LIBs (if Australia had selected SEA-J).

Mainly by Anonymous 

13 comments:

Anonymous said...

Hi Pete

The followings are totally my personal point of view.

There was another SEA-J lengthened by 8m. In this model, main motor section (12) was lengthened by 2m to imrove performance of main motor. As SEA-J transits long range at high speed, durability of main motor should be improved by proper measures such as adoption of tandem connection of two main motors which results in longer length.

Neodymium magnet and bearing are used for submarine Permanent Magnet Synchronous Motor (PMSM) and experience thermal degradation and wear, respectively. To prevent from the damage, cooling of Neodymium magnet is conducted, and reduction of rotation speed/load and cooling of bearing are conducted.

Soryu MKI equips with one main motor consisted of two rotors and two bearings, and its maximum output is 6MW. If two small main motors (eg. 4MW), each of which consisted of single and smaller rotor and two bearings, are tandemly connected, load on each bearings will be significantly reduced improving durability of motor.

Regards

Peter Coates said...

Thanks for your comment Anonymous

Drawing from https://en.wikipedia.org/wiki/Neodymium_magnet provides more background on "Neodymium magnet and bearing are used for submarine Permanent Magnet Synchronous Motor (PMSM)" :

A neodymium magnet (also known as NdFeB, NIB or Neo magnet), is the most widely used type of rare-earth magnet.

Neodymium magnets:

- are permanent magnets made from an alloy of neodymium, iron and boron to form the Nd2Fe14B tetragonal crystalline structure.

- were developed independently in 1982 by General Motors and Sumitomo Special Metals,

- are the strongest type of permanent magnet commercially available.

- have replaced other types of magnets in the many applications in modern products that require strong permanent magnets...

Regards

Pete

Anonymous said...

Hi Pete (continued from 19/1/18 1:37 PM)

RENK bearings for naval application are introduced [1]. A stern side picture of SIEMENS PERMASYN is shown in figure 3 (page2). Most western submarine builders including Naval Group and TKMS adopt products of this company (page 4).

Electrical environment of motor also affects on degaradation of Neodymium magnet.

[1] https://www.google.com.au/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwj6xObMiePYAhVGTLwKHb-xAt0QFggnMAA&url=http%3A%2F%2Fwww.renk.de%2Fdownload.php%3FFile%3DL2RhdGEvd3d3Y3VzdC9uZTItODE0Ni9odG1sL2Ntc19tZWRpYS9tb2R1bGVfb2IvMC8zMjBfMV9Qcm9wdWxzaW9uX01vdG9yX0JlYXJpbmdzX2FuZF9UaHJ1c3RfQmVhcmluZ3MucGRm%26Filetype%3Dpdf%26Filename%3DPropulsion_Motor_Bearings_and_Thrust_Bearings.pdf&usg=AOvVaw04NUJ0QZJPyaagxmu8sUZM
(Propulsion Motor Bearings and Thrust Bearings)

Regards

wispywood2344 said...

Hi Pete.

KHI says that the diesel engine of 26SS is 12V25/25SB.[1]
And in the ATLA central procurement list of FY27(2015), there is an item of 27SS genset, but the classification of its specification is not "新(new)" nor "改(modified/revised)" but "旧(old/conventional)".[2]
Also, in the list of FY28(2016), the classification of 28SS genset specification is "旧".[3]
In contrast, in the list of FY29(2017), the classification of 29SS genset specification is "改".[4]
This suggests that the diesel genset for Soryu Mk2 is the same model of Soryu Mk1, and is different from 29SS genset.
The newly developed diesel "12V25/31S"[5] is to be installed in 29SS.

By the way, in the English-speaking countries, it is said that the range of Soryu class is "6100NM@6.5 kt".
As you can see the Wikipedia-EN, this description is quoted from GlobalSecurity, and is stated as an ESTIMATED AIP range.[6][7]
In other words, GlobalSecurity estimates that Soryu Mk.1 can dive for 39 CONSECUTIVE DAYS with a speed of 6.5kt using AIP.
It is IMPOSSIBLE.
And, the description "6100NM@6.5kt" exists in GlobalSecurity before 18/09/2008, presedes the commision of 16SS.[8]
So I think that the range "6100NM" is INCREDIBLE.

[1]https://www.khi.co.jp/news/detail/20171106_1.html
[2]http://web.archive.org/web/20160417103243/http://www.mod.go.jp/atla/souhon/supply/jisseki/choutatuyotei_pdf/27_tokukan.pdf#page=2
[3]http://web.archive.org/web/20170322113436/http://www.mod.go.jp/atla/souhon/supply/jisseki/choutatuyotei_pdf/33_kansen.pdf#page=4
[4]http://www.mod.go.jp/atla/souhon/supply/jisseki/choutatuyotei_pdf/33_kansen.pdf#page=4
[5]http://www.mod.go.jp/j/yosan/gaisan/h30/gaisanyoukyu.pdf#page=488
[6]https://en.wikipedia.org/wiki/S%C5%8Dry%C5%AB-class_submarine
[7]https://www.globalsecurity.org/military/world/japan/2900ton-specs.htm
[8]http://web.archive.org/web/20080918035920/www.globalsecurity.org/military/world/japan/2900ton-specs.htm

Regards
wispywood2344

Peter Coates said...

Hi wispywood2344

Thankyou for your comments.

I will write next week about 29SS having a modified "12V25/31S" diesel.

Are there any Japanese sources (Japanese wikipedia?) that provide different Soryu class ranges (in nm or km)?

Regards

Pete

Anonymous said...

Pete
Kilo fire in Vladivostok
http://www.thedrive.com/the-war-zone/17853/fire-at-russias-vladivostok-submarine-base-sure-doesnt-look-like-an-exercise
KQN

Peter Coates said...

Thanks KQN

I've written about possible reasons next article at http://gentleseas.blogspot.com.au/2018/01/suspicious-russian-submarine-fire.html .

Regards

Pete

Anonymous said...

Hi Pete

In 27SS and 28SS, performance at middle-high speed (such as maximum silent speed) will be improved and I believe that proplusion motor is modified for this purpose [1].

[1] The first year cost (cost for new instrument, etc) of this motor is appropriated and suggesting the motor is actually new one.

Regards

Anonymous said...

Hp Pete

You know, your analysis about Soryu Mk.2 is referred
by Japanese maritime military magazine "J Ships(the February issue)".

Try read it if you're interested, or you can recruit some translators in your article :)

best regards

Tanaka

Anonymous said...

Hi Pete

I've tried to translate the "J Ship" article(written by Isaku Okabe, a Japanese military critic) into English.

The article translation is below...


*********************************************************************************

"The increasing capability of stealth cruising thanks to the longer underwater duration.

There are some estimations of performance comparison between Soryu class and 27SS
in a blog written by a foreigner who is familiar with submarine matters.
In the blog, 27SS is called "Soryu Mk.2" and its maximum period of continuous cruising below the surface
at a speed of 4 knot/h is estimated to be 7~9 days compared to that of Soryu's 3~3.5days.
The blog says the general period of continuous cruising below the surface also increases to 6~8 days
though the current Soryu class can cruise only 1~1.5 days.
As much, so called "Soryu Mk.2" will be able to conduct secret patrol without using snorkel much longer time.
In regard to cruising at a speed of 18 knot/h, "Soryu Mk.2" will be able to do it continuously for 3~4 hours
which is 3~4 times longer than current Soryu's.

The time required for charging batteries for Soryu class is estimated to be 5~10 hours, whereas the "Soryu Mk.2"
needs just 1~2 hours, which makes the latter much more stealthy.
Supposing the mission period is 60 days, "Soryu Mk.2" requires 8~10 times of charging compared to 40~60 times for Soryu class.
Using snorkel for charging batteries means spoiling confidentiality, so you may have to move from your current area
if you want to make absolutely sure.
LIBs can save the number and peiod of times to use snorkel,which provide submarines much longer time to be stealthy
and the capability to spare the number and peiod of times to move away from patroling area,
resulting in much more efficient use of submarines.
It goes without saying that they're estimations by a foreigner and no one knows if they're correct or not,
but at least they can be good indicators to infer the progress of submarines by LIBs.

However, changing from AIP plus LABs to LIBs is not so much simple as just changing the type of batteries.
Many points have to be modified such as whole power system and safety management system for the realistic and safe use of new batteries.
The 11th and 12th Soryu class submarines ,which correspond to what the foreigner calls "Soryu mk.2",
won't get so much big modifications except for batteries.
Their bodies, armaments, sensors and controlling systems remain almost the same as current Soryu class."

Peter Coates said...

Hi Tanaka

Thankyou so much for your translation from Japanese to English of the Soryu Mk.2's snorkeling performance. Soryu Mk.2's snorkeling performance findings are based on article's written by Anonymous and I on Submarine Matters.

I'll write an article on your translation today.

Regards

Pete
(aka "a foreigner" :)

Anonymous said...

Hi Pete

It's greatful if my contribution helped you.

Regards

Tanaka

Anonymous said...

Hi Pete (continued from 22/1/18 3:46 PM)

In Soryu MK II, modification of propulsion motor [1] accompanied with equipment of LIBs should be emphasized. LIBs provide various benefits such as indiscretion ratio (IR), flexibility of operation and high speed performance at submerge. High power diesel genartors (12V25/25SBs) and newly modified propulsion motor (SMC-8B) assist the former two and the latter, respectively. In Soryu MK I, low speed performance is emphasized because of low effective capacity of LABs. In Soryu MK II, high speed performance will be emphasized, because drastically improved effective capacity allows high speed submerge for much longer period. In other words, main target of SMC-8B [requested change made :) ] is improvement of maximum silent speed and key factors will be optimized to reduce vibration/noise, in my opinion. As result, maximum speed somewhat changes as shown in [2, 3]. As even tiny improvement of maximum speed for only 5min needs higher power, I do not think such tiny improvement has meaning in actual operation.

[1]Budeget on MoD
Types of propultion motor of Soryu MKI and MKII are SMC-8 and SMC-8B where B means first revision. Degree of revision can be measeured by the first year cost which is cost for new equipment and so on in the first year. In SMC-8B, the first year cost was budgeted suggesting that SMC-8B experienced huge modification or that it is actually new model.

[2] “FY2014 Annual Report on Life Cycle Cost Management”, Equipment Procurement and Construction Office, Ministry of Defense (MoD), page 78, Tabale 2.
Maximum surbmerge speeds of 26SS(Soryu MKI LABs+AIP) and 27SS (Soryu MKII LIBs) are 20knot/h and ca.20knot/h.

[3]https://ja.wikipedia.org/wiki/%E3%81%9D%E3%81%86%E3%82%8A%E3%82%85%E3%81%86%E5%9E%8B%E6%BD%9C%E6%B0%B4%E8%89%A6
“Current of LIBs at discharge is low than that of LABs. Maximum surbmerge speeds of 26SS(Soryu MKI LABs+AIP) and 27SS (Soryu MKII LIBs) are 20knot/h and ca.20knot/h. Judging from these fact, maximum submerge speed of MK II seems to become low.” ---- This explanation is wrong, because current of LIBs is sometimes higher than that of LABs.

Regards