Recently, on the pages of the Military Review, controversy has unfolded about the advantages of new power sources for the electric propulsion of the Japanese submarine "Oryu" ("Dragon-Phoenix"), the penultimate unit in the series of submarines of the "Soryu" type. The reason for the discussion was the admission to the fleet of the self-defense forces of the eleventh (in a series of twelve ordered submarines) submarine, armed with a lithium-ion accumulator battery (LIAB).
Against this background, the fact of the creation and trial operation of an air-independent power plant (VNEU) of the so-called second stage remained completely unnoticed. The FC2G AIP was developed by engineers and designers from the French Naval Industrial Group (NG), formerly DCN. Earlier, the same concern created a VNEU type MESMA for the Agosta-90B submarine, operating on the basis of a closed-cycle steam turbine.
It is logical to ask the question: haven't there been attempts to produce hydrogen directly on board a submarine before? Answer: have been undertaken. The Americans and our scientists were engaged in the reforming of diesel fuel to obtain hydrogen, as well as the problem of direct generation of electrical energy from chemical bonds of reagents. But success came to NG scientists and engineers. French engineers managed to create a unit that, by reforming the standard OTTO-2 diesel fuel, receives high-purity hydrogen on a submarine boat, while German submariners are forced to carry H2 stocks on board their type 212A boats.
The importance of the NG Concern's creation of an ultra-high purity (99, 999% purity) hydrogen production unit directly on board the submarine has not yet been fully appreciated by naval specialists. The emergence of such an installation is fraught with colossal opportunities for the modernization of existing submarines and the creation of projects for new submarines, to increase the duration of their continuous stay under water without surfacing. The relative cheapness and availability of OTTO-2 fuel when obtaining free hydrogen for use in the VNEU fuel cells at the ECH will allow the countries with this technology to make significant progress in improving the performance characteristics of submarines. Mastering this type of anaerobic propulsion systems is much more profitable than previously proposed.
And that's why.
1. VNEU on EHG operate two times quieter than a Stirling engine, because they simply do not have rotating parts of the machine.
2. When using diesel fuel, it is not necessary to carry on board additional tanks for storing hydride-containing solutions.
3. The anaerobic propulsion system of the submarine becomes more compact and has a lower thermal effect. All components and systems are collected in a separate eight-meter compartment, and are not scattered across the submarine compartments.
4. The influence of shock and vibration loads on the installation is less critical, which reduces the possibility of its spontaneous ignition, which cannot be said about lithium ion batteries.
5. This setup is cheaper than LIAB.
Some readers may reasonably argue: the Spaniards also created an anaerobic bioethanol reformer (BioEtOH) to produce highly purified hydrogen on board the submarine. They plan to install such units on their submarines of the "S-80" type. The first AIP is planned to be installed on the submarine "Cosme Garcia" in March 2021.
In my opinion, the disadvantage of the Spanish installation is that, in addition to cryogenic oxygen, containers for bioethanol must also be placed on board, which has a number of disadvantages in comparison with the common OTTO-2 fuel.
1. Bioethanol (technical alcohol) is 34% less energy intensive than diesel fuel. And this determines the power of the propulsion system, the submarine's cruising range, and storage volumes.
2. Ethanol is hygroscopic and highly corrosive. And all around - "water and iron."
3. When 1 liter of bioethanol is burned, the same amount of CO is released2as the volume of fuel burned. Therefore, it will be notable to “bubble up” such an attitude.
4. Bioethanol has an octane rating of 105. For this reason, it cannot be poured into the diesel generator tank, since the detonation will blow the engine into bolts and nuts.
Therefore, it is still preferable to VNEU based on diesel fuel reforming. DPL fuel tanks are very voluminous and in no way depend on the availability of additional tanks for industrial alcohol for the operation of the "bioethanol" plant. In addition, a single OTTO-2 fuel will always be in abundance at any naval base or base. It can even be obtained at sea from any ship, which cannot be said about alcohol, albeit technical. And the vacated volumes (as an option) can be given for the placement of oxygen. And thereby increase the time and range of submarine diving.
One more question: is LIAB needed then at all? Answer: certainly needed! Although they are expensive and very high-tech, they are afraid of mechanical damage, in which they are fire hazardous, nevertheless, they are lighter, can take any form (conformal), at least 2-4 times (compared to lead-zinc acid batteries) have a higher capacity stored electricity. And this is their main advantage.
But then why such a boat carrying LIAB, some kind of VNEU?
An anaerobic power plant is needed in order not to "stick out" the underwater diesel engine (RDP) device on the sea surface, in order to launch or start a diesel generator to tamp the battery charge. As soon as this happens, two or three signs unmasking the boat will immediately appear: a breaker on the water surface from the RDP shaft and radar / TLV / IR-visibility of this retractable device. And the visual (optical) visibility of the submarine itself, "hanging" under the RDP, even from space will be significant. And if the exhaust gases of a working diesel engine (albeit through water) into the atmosphere, then the gas analyzer of the BPA (PLO) aircraft will be able to record the fact that a submarine is in the area. This has happened more than once.
And further. No matter how quietly a diesel or diesel generator works in a submarine compartment, it can always be heard by the sensitive ears of the enemy's PLO forces and means.
All these disadvantages can be avoided by the joint use of AB and VNEU. Therefore, the joint use of VNEU and supercapacity storage devices of electrical energy, such as magnesium, silicon-metal or sulfur batteries, in which the capacity is expected to be 5-10 times (!) Greater than that of LIAB, will be very promising. And it seems to me that scientists and designers have already taken this circumstance into account when developing projects for new submarines.
So, for example, it became known that after the completion of the construction of a series of submarines of the "Soryu" type, the Japanese will begin the design and R&D of the next generation submarine. Recently, the media reported that it would be a submarine of the 29SS type. It will be equipped with a single (all-mode) Stirling engine of improved design and probably a capacious LIAB. And such work, together with American scientists, has been carried out since 2012. The new engine will have nitrogen as the working fluid, while helium on the Swedish cars.
Military analysts believe that the new ship, in general terms, will retain the very successful shape worked out on the Soryu-class submarine. At the same time, it is planned to significantly reduce the size and give a more streamlined shape to the "sail" (the fence of retractable devices). The horizontal bow rudders will be moved to the bow of the boat hull. This will reduce the hydrodynamic resistance and the level of intrinsic noise when water flows around the submarine hull at high underwater speeds. The propulsion unit of the submarine will also undergo changes. The fixed pitch propeller will be replaced with a water jet. According to experts, the submarine's armament will not undergo significant changes. As before, the boat will retain six bow 533-mm torpedo tubes for firing heavy torpedoes ("Type 89"), anti-submarine torpedoes and Sub Harpoon-class cruise missiles, as well as for laying minefields. The total ammunition on board the submarine will be 30-32 units. At the same time, its typical load (6 new anti-ship missiles, 8 type 80 PLO torpedoes, 8 type 89 heavy torpedoes, self-propelled GPA and electronic warfare vehicles) will apparently be retained. In addition, it is assumed that the new boats will have active anti-submarine protection (PTZ), possibly air defense, launched from a torpedo tube.
Work on the creation of a new submarine is planned to be carried out in the following terms: R&D in the period from 2025 to 2028, construction and commissioning of the first submarine building of project 29SS is expected in 2031.
According to foreign experts, the states of the Indian and Pacific Oceans will soon need to modernize and renew their fleets. Including the submarine forces. For the period up to 2050, the need for submarines will be about 300 units. None of the potential buyers will buy boats that are not equipped with VNEU. This is convincingly evidenced by the tenders for the purchase of submarines held by India and Australia. India bought French Scorpen-class nuclear submarines, and Kanbera chose Japanese Soryu-class nuclear submarines for her fleet. And this is no coincidence. Both of these types of boats have VNEU, which ensure that they stay under water without surfacing for up to 2-3 weeks (15-18 days). Japan currently has eleven nuclear submarines. South Korea is building its K-III type submarine with lithium-ion storage batteries.
Unfortunately, we still cannot boast of success in creating submarines armed with non-nuclear air-independent propulsion systems. Although work in this direction was carried out, and it seemed that success was not far off. It remains to be hoped that specialists from CDB MT "Malakhit", CDB MT "Rubin", FSUE "Krylovskiy State Scientific Center", Central Research Institute "SET" in the near future will still be able to create a Russian air-independent engine for non-nuclear submarines, similar or better than foreign analogues. This will significantly increase the combat readiness of the naval forces, strengthen our position in the export of submarines to traditional buyers, and help conquer new markets for the supply of our naval products.
