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Liaoning - Propulsion

China's first aircraft carrier, Liaoning, is a former Soviet-era vessel that China acquired from Ukraine in 1998. It arrived without an engine or electrical systems and took years to modify. The Liaoning is conventionally powered, seemingly using a Chinese propulsion system similar to that of the Russian Navy Kuznetsov, consisting of eight boilers and four steam turbines (50,000 shp each). A conventional carrier power system is equivalent to a medium-sized fuel thermal power plant.

The Liaoning transformation period was a major challenge to install the huge new boilers and other heavy, large-scale replacement equipment. For the Liaoning, Harbin Boiler Co. provided boilers and China Erzhong Group (Deyang) Heavy Industries Co Ltd built the steam turbines, respectively, The enterprises also provide boilers and steam turbines for the civilian power plants.

The ship undertook her first sea trials from 10 August 2011 to 15 August 2011. The carrier completed sea trials in early August 2012. During sea trials Liaoning experienced a steam burst in the engine compartment which forced crew to evacuate some parts of the ship, and the ship lost power. In October 2014, sina.com reported "a large amount of hot water and steam spewing out of the cabin instantly submerged in the water vapor." The problem was ultimately resolved and power was restored, although the time duration of the problem has not been released by military officials. Her sister ship Kuznetsov has also been disabled several times by engine failures.

The website http://mil.news.sina.com.cn reported 09 November 2016 that the "Kuznetsov chimney always emitted smoke, indicating that the ship's power system had been a problem, and needed to undergo a thorough transformation. The Liaoning ship, through the Chinese shipbuilding industry and the Chinese navy, carefully developed support and maintenance of the ship steam turbine in the best condition, known as the Navy's best steam turbine."

As initially designed, the Project 1143.5 Varyag was to have been equipped with steam turbine engines providing 200,000 shp. Although estimates vary, this was estimated to be sufficient to propel the 58,600-67,500 tons full load ship to a speed of 29-32 knots. This machinery is slightly larger than that of the predecessor Project 1143.4 Kiev, which also had 8 boilers and four turbines, with an aggregate of 180,000 - 200,000 shp. The Kiev had two engine rooms, each of which was about 20 meters long and 10 meters tall. The width of the engine room is unclear, but their mid-ship location is constrained by the 32.6-32.7 meters waterline beam to less than 25 meters.

Evidence suggested that as of 2013 AVIC’s aviation gas turbine engine makers were still having trouble maintaining consistent quality control as they scaled up production of the developed engines, causing problems with reliability. That is where overseas suppliers play a useful role to reduce risk, match complementary expertise, and enhance financing and market access. As is well known, China is deficient in marine propulsion technology, and has not produced significant steam turbine or gas turbine marine propulsion plants. Only a few PLAN warships are equipped with such propulsion plants, which are standard in navies around the world, and the few Chinese installations involve plants of foreign manufacture. China's commercial and military surface vessels are uniformly outfitted with marine diesel engines, many of foreign design built under license.

Instead, some suggested that marine gas turbine engines from Ukraine were fitted. The Ukrainian company Gas Turbine Research & Production Complex Zorya-Mashproekt is one of the world leaders in gas turbine construction. The company designs and constructs gas turbines for sea-going merchant fleet and navy, for power industry and gas transport mains opening up new possibilities for the world. Company products are provided to Russia, Byelorussia, India, China, Vietnam, Singapore, South Korea and other countries. The company's largest engine, the Gas turbine engine UGT 25000, is a three-shaft gas turbine comprising two-spool gas generator and free power turbine. It has a rated power of 26,700, or about 36,000 shp. Six such engines would be more than adequate to power the ex-Varyag.

"Han Defense Review" magazine reported in February 2011 that the aircraft carrier construction process provided extensive technical assistance, particularly in the power plant, but also experts in Ukraine also participated in the procurement of China in 1999, "Varyag "aircraft modification work. "Han and Defense Review," pointed out that China "Varyag" modification has been completed, the assembly of power units developed in Ukraine. "Han and Defense Review," edited by Andrei Chang said that Ukraine has also helped China built in Harbin, a boiler and turbine manufacturing plant, production of military boilers, turbines, steam equipment, used to make use of Chinese-made aircraft carrier catapult system, landing block device and the like Russia, "Admiral Kuznetsov" carrier aircraft equipment and other systems.

Absent foreign supply, China might have resorted to diesel engines for the ex-Varyag. The largest American warships with diesel propulsion are the US Navy's LSD-41 Whidbey Island class landing ship dock amphibious assault ships, which have four Colt Industries 16 Cylinder Diesels providing a total of 41,600 shp, which propel these 16,360 ton ships to a speed of 20 knots. In general, however, the use of diesels requires that several units be combined to drive a common shaft. This requirement results in severe space and arrangement problems. Among other disadvantages is the fact that periodic engine overhaul and progressive maintenance are required. These result in frequent down periods, which, because of the number of similar units, may not increase the amount of necessary in-port maintenance time, but do decrease the amount of time the ship has full power available while at sea.

Wärtsilä is a global leader in complete lifecycle power solutions for the marine and energy markets. Many Wärtsilä engines are licensed for production in China, and are representative of the types of marine diesel engines available from Chinese industry. Marine diesels provide great flexibility in the selection of engine power and speed to obtain the optimum fit to ship and propeller requirements and best installation economy, with a wide range of power and speed covered by each engine. Their power is frequently expressed in kilowatts, and 1 kilowatt is equal to 1.34 hp [1 hp = 0.746 kw].

Conventional medium-speed diesel engines have often been used as the main engines bulk carriers. The Wärtsilä 64 is the world's most powerful medium-speed engine. It offers an outstanding range of power options with minimum size - 17,200 kW [23,056 hp], measuring 12.74 meters long, 4.165 meters wide and 6.415 meters high, with an overall weight of 295 tonnes.

Small marine diesels such as the Wärtsilä RT-flex35 low-speed marine diesel engines are tailor-made for the economical and reliable propulsion of many types of small and medium-sized commercial vessels. They are designed to give the best powers and speeds for a wide variety of ship types, such as handysize bulk carriers and product tankers, general cargo vessels, reefers, feeder container ships, and small LPG carriers. Available with five to eight cylinders, the RT-flex35 cover a power range of 3475-6960 kW [4658-9329 hp] at 142-167 rpm. The highest power is delivered by the eight cylinder version, measuring 5.7 meters long, 2.3 meters wide and 8.1 meters high, with an overall weight of 89 tonnes [in practice auxiliary machinery could dictate an installation nearly three times this wide].

The Aioi Works of Japan's Diesel United, Ltd built the first Wartsila-Sulzer RTA96-C turbo charged two-stroke diesel ship engine, the most powerful and most efficient prime-mover of super ships in the world today. These engines were designed primarily for very large container ships. The engine weighs in at 2,300 tons and is capable of delivering 109,000 horsepower. The first 14-cylinder Wärtsilä RT-flex96C marine engine has a maximum continuous power output of 80,080 kW (108,920 bhp) at 102 rpm. Measuring 27.3 m long and 13.5 m high, it has an overall weight of 2300 tonnes.

At the lower end, the Wärtsilä 64 medium-speed engines might be arranged in a three abreast installation [12.74 meters long, versus 20 meters available] in each engine room, for a total of a half-dozen engines, providing 138,000 hp, about two-thirds that originally planned. The 9,000 hp RT-flex35 low-speed engines might be arranged in a pair [2 x 5.7 m length = 11.4 meters, versus 20 meters available] of four abreast installations [6 meters width for each engine], for a total of a dozen engines, providing 108,000 hp, just over half that originally planned. A pair of RTA96-C low-speed engines would provide 218,000 horsepower, a bit more than that originally planned, but the engine's dimensions exceed those of the existing engine rooms by wide margins [27.3 m long versus 20 meters, and 13.5 m high versus 10 meters].

A more sophisticated naval engineering analysis would certainly produce more precise results, and might produce somewhat different results. But it seems more likely than not that the ex-Varyag outfitted with marine diesel engines would be underpowered relative to the original design, and consequently slower than the original design. With a best speed in the neighborhood of about 20 knots [the standard speed for American amphibious ships], ex-Varyag would be considerably slower than the 30-knot standard for American aircraft carriers and escort ships. As such, ex-Varyag would seem far more suited as an aviation training ship than as a operational tactical combat unit, though it might have some combat utility under some circumstances.




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