What is an icebreaker?

Definition of scientific terms of icebreaker

Chinese name: ice breaker English name: Icebreaker Definition: A ship that uses the gravity and kinetic energy of the hull or other methods to break the ice and open a passage for other ships to pass through the ice area. Discipline: ship engineering (first-class discipline); Ship types and ship inspection, international conventions and certificates (two disciplines) are examined and published by the National Committee for the Examination and Approval of Scientific and Technological Terminology.

Icebreaker is a kind of service ship, which is used to break the ice layer on the water surface, open a channel, ensure the ship to enter and leave the frozen port and anchorage, or guide the ship to sail in the ice area. Divided into rivers, lakes, harbors or ocean icebreakers. The hull is short and wide, with a small aspect ratio, the bottom of the ship is tilted upward from beginning to end, and the head column is pointed forward, so the overall strength is high. The head, tail and waterline areas are reinforced with thick steel plates and dense skeletons. The propulsion system mostly adopts double-shaft or more propeller devices, and the electric propulsion is powered by diesel engine. Propeller and rudder are protected and reinforced. When breaking the ice, the ice squeezed by the head keeps breaking the ice or breaks it repeatedly.

icebreaker

The first icebreaker was the "Ermak" designed by Russians and built by Britain for Russia in 1899. A service ship used to break the ice layer on the water surface, open a waterway, ensure ships to enter and leave frozen ports and anchorages, or guide ships to sail in the ice area. Divided into rivers, lakes, harbors or ocean icebreakers. The hull is short and wide, with a small aspect ratio, the bottom of the ship is tilted upward from beginning to end, and the head column is pointed forward, so the overall strength is high. The head, tail and waterline areas are reinforced with thick steel plates and dense skeletons. The propulsion system mostly adopts double-shaft or more propeller devices, and the electric propulsion is powered by diesel engine. Propeller and rudder are protected and reinforced. When breaking ice, the head squeezes the ice continuously or repeatedly.

history

icebreaker

1864, the Russians converted a small boat "Pelot" into the first icebreaker in the world, in order to keep the navigation between Kranstadt and Oranbaum during the frozen period, and the icebreaker "Ermak" built by Britain for Russia was the first icebreaker sailing in the Arctic. 19 12 years, the icebreakers Tongling and Ling Kai were built for the first time in China, with a displacement of 4 10 ton and a power of 688 HP. With the development of Antarctic scientific research, modern icebreaker has become an important equipment for polar scientific research, which is not only used to break ice, but also responsible for transportation and marine survey. This icebreaker has a long voyage, slow ice breaking progress and high fuel consumption. The use of nuclear propulsion can meet its special needs, but it is expensive. 1957, the Soviet-built icebreaker Lenin was the first nuclear-powered icebreaker in the world. icebreaker

There have been many severe ice conditions in China waters, of which 1936, 1947 and 1969 are the most serious, and 1969 is the most serious. 1 February-March, 1969, the largest ice sheet appeared in Bohai Sea, and the peak of the ice age was delayed by1month compared with normal years, and the ice age in Bohai Bay reached 4 months. When the ice sheet is severe, the outer edge of the ice is only 35 nautical miles away from the Bohai Strait, and the whole Bohai Sea is almost completely covered by sea ice. The ice sheet lasts for 40-50 days, and the small ice mound is 5 meters high, 65,438+. Haijing-2 platform was pushed down by flowing ice, which caused serious losses. The State Council attaches great importance to this. Zhou Enlai instructed to break the ice, and the air force bombed to break the ice. At the same time, it instructed the navy to build an icebreaker. The navy completed the construction of sea ice 722 and 72 1 (built by Shanghai Shipyard, launched on February 26th, 0969 with 65438+) in 0/00 day, and launched on February 26th. Since 1989, the navy has independently carried out sea ice investigation tasks. The purpose of sea ice survey is to obtain the data of sea ice situation, hydrology and meteorology in winter, study the fluctuation law and physical and chemical properties of sea ice, and provide realistic basis for sea ice forecast.

trait

The length-width ratio of an icebreaker is quite different from that of a general seagoing ship. It is short in the longitudinal direction and wide in the lateral direction, so it can open a wider channel. An icebreaker with a displacement of 3 sea ice 72 1.

7000 tons of modern icebreaker with 7.35× 107 watt, with a length of194m and a width of 32.2m.. The bow shell of the icebreaker is made of steel plates with a thickness of at least 5 cm, and the interior is supported by dense steel members. The waterline of the hull is reinforced by impact-resistant alloy steel. Icebreakers generally break ice in two ways. When the ice thickness is less than 1.5m, the "continuous" method is often used. Mainly relying on the power of propeller and bow to split the ice and crush it, it can sail 9.2 kilometers in the ice sea every hour. If the ice layer is thick, the "impact" ice breaking method is adopted. The bow of the collision icebreaker is shallow, so it will easily rush to the ice, and the ship will crush the thick ice below. Then the icebreaker goes backwards for a certain distance, and then rushes to the ice in front with full horsepower, crushing the ice under the ship. Over and over again, a new channel was opened. Fuel-driven icebreakers mostly use diesel engines to drive engines to generate electricity, and motors to drive propellers (driven by combined units). The driving power can reach millions of watts, which can meet the needs of long-term ice-breaking navigation. 1957, the former Soviet Union built the first nuclear-powered icebreaker Lenin. Its power core is thermonuclear reactor, which is the only icebreaker with high-pressure steam in China.

Push the steam turbine and drive the propeller to push the ship. If the nuclear-powered icebreaker carries 10 kg of uranium, it is equivalent to carrying 25,000 tons of standard coal, which can be used in the frozen sea far from the port all the year round. The icebreaker is equipped with 2 ~ 4 propellers. The icebreaker is equipped with two propellers at the stern and near the bow. The propeller at the bow pumps out the water under the ice, weakening the support of the ice layer and splitting it into pieces. The ship is propelled by the last two propellers. For the icebreaker, two propellers are symmetrically installed on both sides of the stern in order to enable the ship to rush to the impact layer. Because many sea areas will freeze in winter, many countries have icebreakers, and some countries near the North Pole also have special Arctic icebreakers. Russia has seven to eight nuclear-powered polar icebreakers, six of which can perform tasks. The US Coast Guard's medium-sized polar icebreaker fleet is mainly composed of three ships, of which Healy is called the latest and strongest icebreaker in the United States. In addition, Britain, Norway, Canada, Japan, Finland and other countries also have their own icebreakers. China's "Snow Dragon" is also a polar icebreaker. Generally speaking, this method is used to deal with ice less than half a meter. When encountering thick ice, you need to subdue it with the impact of the ship. At this time, the icebreaker retreated and hit the ice with all its mass. What works at this time is not gravity, but the kinetic energy of the moving ship; The ship seems to have become a low-speed but heavy shell, a hammer. Icebergs several meters high, the icebreaker must hit them several times with a solid bow to break them. So the icebreaker is made of thick steel plate, which is very strong.

principle of operation

whale

icebreaker

When taking a bath, before jumping out of the bathtub, open the drain hole and continue to lie at the bottom of the bathtub. At this time, the part of your body in contact with water is gradually increasing, and you also feel that your body is gradually getting heavier. In this case, you can see very clearly that as soon as your body comes out of the water, the gravity it lost in the water will recover immediately. Whales are not so smart. When they do the same, the result is disaster: it will be crushed to death by its amazing gravity. No wonder the whale, originally a mammal, wants to live in water: the buoyancy of water can keep it from being crushed to death by gravity.

icebreaker

icebreaker

Does it keep cutting ice with the pressure of the bow? If you think that, you are all wet. This is how the ice crusher works. Generally, you can only chop thin ice. Real icebreakers break ice by gravity. There are one or several ballast tanks at the bow and stern of the ship. When breaking the ice, first empty the front cabin, then fill the back cabin with seawater, and the front cabin will tilt upward and rush to the ice with great horsepower. Then, empty the rear cabin, fill the front cabin, and crush the ice by weight-if the left and right cabins are too narrow, fill and empty the left and right cabins in turn to shake the ship and break the ice. The work of the icebreaker is based on the same physical phenomenon: the part of the hull exposed to the water still has its original "land" weight, because its weight is not offset by the buoyancy of water. Don't think that the icebreaker is constantly cutting ice with the pressure of the bow when driving. Icebreakers don't work like this; They work like ice cutters, such as the famous "Ritke" in 1930s. This working method can only be used to deal with thin ice. icebreaker

Real ocean icebreakers work in another way. The powerful machine on the icebreaker can move the bow to the ice when driving, so the underwater part of the bow is very inclined. When the bow appeared on the water, it regained its full weight, which could crush the ice. In order to strengthen the strength, sometimes the water storage tank at the bow will be filled with water "liquid ballast". When the thickness of ice is less than half a meter, the icebreaker works like this. When encountering thick ice, you need to subdue it with the impact of the ship. At this time, the icebreaker retreated and hit the ice with all its mass. At this time, it is not the weight that does work, but the kinetic energy of the moving ship; The ship seems to have become a low-speed but heavy shell, a hammer.

experiment

Markov, a sailor who participated in the famous voyage of "Siberia" across the polar regions in 1932, once described the work of this icebreaker as follows: Among hundreds of icebergs, "Siberia" began to fight in a dense place. For fifty-two hours in a row, the pointer on the signal machine always jumps from "full speed backward" to "full speed forward" During the 4-hour offshore operation of 13 class, the Siberian people rushed to the ice, hit it with the bow, climbed onto the ice and crushed it, and then retreated. Three-quarters of a meter thick ice is slowly melting. Every collision, the hull can move forward by a third.

street corner

But there is still a problem worthy of attention. There is a certain angle between the ship's side and the vertical, but the lower part of some ships is very straight, and even the lower part of some ships is concave inward, just like the container ship below. So why does the icebreaker have that structure? Here is a question. As we all know, the ice surface is slippery, so when the icebreaker walks on the icy sea, what is the friction coefficient between the hull and the ice surface? Think about walking on an icy road in winter. However, scientists have found that the friction between the steel plate of the hull and the ice is not as small as expected, and some ships have been wrecked. It is found that the friction coefficient between the ice surface and the steel shell of the new ship reaches 0.2, which leads to a problem. If the angle between the ship's side and the vertical surface is too small, the ice will crush the ship.

pressure

The pressure of ice on the ship is divided into two forces, the force R perpendicular to the ship's side and the force F tangent to the ship's side. The included angle between P and R is equal to the inclination angle between the ship's side and the vertical, and the friction Q of ice against the ship's string is equal to the force R multiplied by the friction coefficient, that is, q = 0.2r If Q is less than F, the force F will push the ice pressed on the ship's hull into the water, and at this time it will slide along the ship's side without damaging the ship; If q is greater than f, friction will prevent the ice from sliding and squeeze the ship's side for a long time. So how to calculate the inclination of the ship's side to the vertical? Quite simply, we have

dip angle

It can be found from the trigonometric function table that the tangent function is 0.2 and the angle is 1 1. That is to say, when α > 1 1, q < F. Based on the above, we can determine the inclination of the ship's side relative to the vertical, thus ensuring the safe navigation of the ship in the middle of the ice. This inclination should not be less than 1 1. This is why icebreakers can't be designed like container ships. Let's take a look at the consequences of the ship described by the crew because they didn't notice the above.

Edit this paragraph model

Icebreaker Perot, Icebreaker Ermak, Icebreaker Lenin, Icebreaker Xuelong and Icebreaker Jiahaibing 72 1. The icebreaker "Haibing 72 1" is made of manganese steel, and its bow deck is 24 mm thick. Its maximum impact force can break ice 1 meter thick. This icebreaker has successfully rescued merchant ships from Norway, Cyprus and other countries trapped in the sea of ice. The ship has a hull length of 84.28 meters, a maximum width of 16 meters, a displacement of 319/0.86 tons, an average draft of 3.68 meters, a maximum horsepower of 3.82 MW, a maximum speed of 16.5 knots, and an endurance of10.

Icebreaking method

icebreaker

Icebreakers generally break ice in two ways. When the ice thickness is less than 1.5m, the "continuous" method is often used. Mainly relying on the power of propeller and bow to split the ice and crush it, it can sail 9.2 kilometers in the ice sea every hour. If the ice layer is thick, the "impact" ice breaking method is adopted. The bow of the collision icebreaker is shallow, so it will easily rush to the ice, and the ship will crush the thick ice below. Then the icebreaker goes backwards for a certain distance, and then rushes to the ice in front with full horsepower, crushing the ice under the ship. Over and over again, a new channel was opened. Fuel-driven icebreakers mostly use diesel engines to drive engines to generate electricity, and motors to drive propellers (driven by combined units). The driving power can reach millions of watts, which can meet the needs of long-term ice-breaking navigation.

Nuclear powered icebreaker

1957, the former Soviet Union built the first nuclear-powered icebreaker Lenin. Its power heart is a thermonuclear reactor, and high-pressure steam drives a steam turbine to drive a propeller to drive a ship. If the nuclear-powered icebreaker carries 10 kg of uranium, it is equivalent to carrying 25,000 tons of standard coal, which can be used in the frozen sea far from the port all the year round. The icebreaker is equipped with 2 ~ 4 propellers.

Edit this paragraph for disaster relief.

With the latest cold air crossing the border, the sea ice area in Bohai Sea and Yellow Sea has increased significantly. According to the satellite remote sensing monitoring of 2065438+65438 of National Satellite Ocean Application Center on1October 00+22, the total sea ice area in the northern part of Bohai Sea and Yellow Sea reached 4 13 12 square kilometers. Li, deputy director of the Disaster Warning Office of the National Marine Environmental Forecasting Center, said that half of the Bohai Sea has been covered by sea ice, and many ships have been stranded at sea, which has seriously affected offshore production such as aquaculture, maritime shipping and oil and gas exploitation. On 23rd, the naval icebreaker "Hai Bing 72 1" went to Bohai Bay to rescue cargo ships and fishing boats trapped by sea ice.

Sea ice disaster

Sea ice is known as the "white killer", and it is also known as the five major marine disasters with tsunami, storm surge, disaster wave and red tide. Since 65438+1October 3, the largest continuous low-temperature freezing weather has occurred in Shandong province since 1967, and freezing phenomena of different degrees have appeared in various sea areas. In particular, the ultra-low temperature in the Bohai Sea for several days has caused a large area of freezing, and the ice layer has been continuously thickened, with an average thickness of 25 cm in most areas, and ice mounds have formed in individual estuaries, with an accumulation height of 65,438 0.2 meters. In Liaodong Bay, Bohai Bay, Laizhou Bay and the northern Yellow Sea, the sea ice area and sea ice density have increased. Among them, the distribution area of sea ice in Liaodong Bay is 20,835 square kilometers, accounting for 67% of Liaodong Bay. The distribution area of Bohai Bay is 944 1 km2, accounting for 59% of the Bohai Bay area. Laizhou Bay covers an area of 4,052 square kilometers, accounting for 43% of the sea area. It is expected that the situation in Bohai Sea and Huang Haibing will continue to develop and may reach the worst level this year by early February. This sea ice disaster is the most serious in Shandong Province in 40 years, with long duration, wide range and thick ice layer. According to statistics, as of 2 1, the number of people affected by sea ice disasters in Shandong Province reached 95,000.

The fishing boat was frozen.

From 65438+1October 14 to 18, along the coast of Bohai Sea, pieces of merchant fishing boats are frozen at sea, such as a joint venture in Chibi, which is spectacular. "I have never seen such a serious ice situation. Listening to the old people in the village, I have never seen so much sea ice so early for decades. " Qiu Guangyuan, a fisherman in Dongying Village, jiaozhou city Yinghai Office, said, "There are more than 200 fishing boats frozen at the dock of our village." The sea ice disaster has seriously affected China's transportation, especially the transportation of coal from north to south, fishery production, offshore oil field operation and the life of people along the coast and islands of the Yellow Sea and Bohai Sea. Liu Tingheng, deputy general manager of Weifang Senda Meigang Co., Ltd. said: "In the past three days, the port has been frozen intermittently. Over the past ten days, more than 100 cargo ships have been unable to dock normally, with a total cargo tonnage of 350,000 tons. There are still more than 30 ships that cannot dock. "

The icebreaker went into battle.

On the afternoon of 22nd, the 74th mobilization meeting of China Navy's ice survey mission was held at a dock in Qinhuangdao. On 23rd, officers and men of the China Navy Ice Investigation Team set sail on the icebreaker "Hai Bing 72 1" to conduct ice investigation and rescue operations around the Yellow Sea and Bohai Sea. Li Qingming, commander of the China Navy's ice survey mission, said: "This ice survey lasted for one week, with a total voyage of more than 900 nautical miles. There are two main tasks. One is to undertake the investigation of the situation in the Bohai Sea and the northern part of the Yellow Sea, and the other is to undertake the task of maritime rescue and disaster relief. " There are usually three ways to rescue ships trapped by sea ice and break the ice. One is the collision method, that is, the ice is crushed by the hull by the power of the icebreaker; The second is the collision method. First, reverse the car for a few meters, and then the two cars drive at full speed to smash the ice. The third method is to store water and break the ice, that is, first pump the water in the hull to the back cabin, then drive the protruding bow to the ice, then pump the water from the back cabin to the front cabin, and break the ice with the help of the weight of water.