035G conventional submarines were stationed in the former site of Jiangnan Shipyard No.3 Dock
At noon on January 19, 2022, the retired Chinese People's Liberation Army Navy Type 035G submarine began to dock as the exhibition hall of the Huangpu Branch of the China Maritime Museum. After that, in the No.3 dock of the old Jiangnan Shipyard, there will be a long-lost industrial sound, and the submarine will begin to repair and sort out the internal facilities. Perhaps in a few months, the Maritime Museum will be able to open navigation and national defense education to the public in the birthplace of Chinese industry, so that the public can understand China's great goal of building a maritime power through navigation and national defense, and combine the excellent farming culture formed by China for thousands of years with the world's open navigation culture, which is of far-reaching significance.
The previous part discussed the origin and development of the propeller, and captain Yi sheep introduced how to transmit the power of the main engine to the propeller on the outboard tail in this part. How is watertightness done? What is the difference between the propeller of a submarine and an ordinary surface ship?
Modern ships are powered by internal combustion engines or external combustion steam turbines. The main spindle transmits power to the propeller through bearings in the hub. The spindle drives the propeller to rotate to push the water behind the boat, using the reaction force of the water to propel the boat forward.
"Yuanwang 1" five-blade propeller
The bearing mounted on the shaft hub is made of natural seawater or lubricating oil, which acts as a lubricant to ensure that the spindle has a minimum friction rotation, so that the bearing reduces friction and heats up, it is not easy to damage the tail shaft, and the tail shaft reaches the maximum power output.
The hub is at the stern of the ship
The material of the bearing is iron pear wood, and yes, it is made of wood. Mainly using seawater for direct lubrication, cooling water lubrication, because the viscosity of water is low, the water film is thin, so its bearing capacity is low. The sealing performance of iron pear wood is poor, and the sediment is easy to accelerate the wear of iron pear bearings with the entry of seawater. Because iron pear wood is more scarce, the price cost is higher. As ships are built larger and larger, the load on the tail shaft continues to increase, and pearwood bearings can no longer withstand the huge tail shaft. Modern ships use white alloy bearings to replace traditional pear wood bearings. White alloy bearings use lubricating oil, in the spindle rotation will form an oil film, so the bearing capacity of white alloy bearings is large, the lubrication performance of the oil is better, and its sealing device can also effectively seal the inside and outside of the board, seawater and sediment are not easy to enter the tail shaft tube, so the wear of the white alloy bearing is small, the life is long, and the work of the main engine and shaft system is relatively stable and reliable.
After solving the problem of external propeller output power and internal and external watertightness of the main bearing, we will talk about the tail propeller of the ship. It is said that the main engine of the modern super 20,000 container ships has a power of 120,000 horsepower, and its spindle terminal propeller has a diameter of 9.8 meters, which is generally 4-5 blades. Most of the super container ships are five paddles, and they are not as bulky and broken as old cattle; the little daughter-in-law rides a mule back to her mother's house slowly and slowly; like a small-footed woman walking on crutches; I don't know that such a large ship can run at a speed of 22.5 knots per hour when it is full of cargo! Cars on the roads of downtown Shanghai can't run at an average speed of 41.67 kilometers per hour! This is simply the speed of the lads!
Ship main engine, spindle and various propellers
How fast the ship sails depends on the oversized structure of the ship's propeller and the number of blades. It can be said that in the case of a host equipped with the same engine speed and power, the more propeller blades of the ship, the greater the corresponding thrust. At the same time, the main engine of the ship can also be designed as a low-speed internal combustion engine. The main engine of the oversized container ships made by Captain Yiyang is a low-speed internal combustion engine, and the general offshore speed limit speed is 104 rpm, and the minimum speed is only 18 rpm at micro-speed.
However, the number of propeller blades is not as much as possible, and naval architects have long been equipped with propellers with different blades for different ships, reducing the propeller slip rate and achieving the maximum effective power.
So, what type of ship is equipped with a propeller with more blades than a large cargo ship?
The submarine with the most propeller blades is the submarine. The advantages of the multi-blade propeller, the speed is stable, the slip rate when advancing in the water is small, there is little vibration, the noise suppression ability is strong, and it is very suitable for the characteristics of submarines in underwater covert combat.
Therefore, the propeller of the submarine is generally five, six, seven blades, of which the effect of the seven-blade blade is the best, according to physical tests, the number of propeller blades is not much different, the asymmetrical blade is less than the symmetrical blade resonance, that is to say, the propeller of the double blade has the highest energy efficiency, vibration and noise suppression ability is the strongest.
Submarine propeller, seven-blade propeller
Although the nine-blade paddle has the greatest thrust, noise suppression and vibration, the technical processing of the nine-blade paddle is extremely difficult. According to the introduction of professional engineers, the propeller blades need to be processed synchronously on a piece of metal material to make the propeller blades best balanced. Synchronous processing of nine-blade propeller requires multiple linkage CNC machine tool turning, which involves the country's shipbuilding industry capacity. Perhaps everyone does not believe that the huge propeller can be like a fair scale, the balance weight error is within a few grams, which is simply the level of a chip lithography machine! In other words, nine-blade propellers are not produced in ordinary countries!
In addition, with the improvement of ship thrusters, some submarines have begun to install deflector propellers, and the noise suppression effect is better. By changing the angle of the deflector, the function of changing the heading can also be achieved, completely replacing the steering gear equipment.
From the steam engine installed in the ship with paddle wheel propulsion, to the steam engine fixed propeller, from the two-blade propeller, to the three-blade, four-blade, five-blade, six-blade, seven-blade, and then to the ultra-advanced nine-blade propeller, and now it has developed into a variable pitch propeller, a fairing propeller, and then a pod-type propeller, in just a hundred years in modern times, the propeller has turned the world upside down!
Variable propeller
Fairing propeller
Pod propeller
Shipbuilding needs the assembly line of professional parts and components producing countries in various countries to cooperate with each other, and various parts and components need to be manufactured by specialized manufacturers in the world, and then purchased from suppliers in order to assemble a modern large ship. The mainland can build the largest ships in modern times, but it does not mean that all the equipment is made by the mainland shipyards, which is the industrial characteristics of modern society.
But this does not mean that our shipbuilding technology can rely on other supplier countries, especially high-end manufacturing technology, still have to overcome difficulties and master it on their own, otherwise, the story of being stuck in the neck by other interested countries will be staged every day.
The construction of ships on the mainland is already on the way, and the nine-blade propeller manufacturing will certainly surpass advanced countries. The mainland's shipbuilding technology is as hard as the ship propeller, some technologies have broken the bottleneck of blockade, by leaps and bounds, the shipbuilding industry will certainly provide the mainland's marine construction, the Maritime Silk Road to provide the most advanced merchant ships, for the arch to defend the sea frontier to create more and more advanced ships.
The "Yuanwang 1" and the 035G decommissioned submarine are in the same frame