Gas turbines, steam turbines, diesel turbines, which are good for surface ship propulsion, what is d

Steam (not gas) turbine: due to the shortcomings of long start-up and preparation time, poor maneuverability, complex pipelines, large volume, high noise, and high fuel consumption under low working conditions, it is rarely used in modern times. However, the steam turbine has its inherent advantages, that is, the technology is mature and reliable, the power is strong, and the transmission efficiency is high, so some of the first steam turbines are still used, in fact, if large warships need to reach a certain speed, they cannot be achieved without steam turbines, such as heavy aircraft carriers in the United States, the so-called nuclear power propulsion is also to promote the operation of steam turbines with nuclear reactors.

Gas (not steam) turbine: Gas turbine is an internal combustion power machine that uses continuously flowing gas as the working medium to drive the impeller to rotate at high speed and convert the energy of the fuel into useful work, and is a kind of rotating impeller thermal engine. The principle of operation is completely different from that of a steam turbine.

Its advantages are small and light, small size and large power-to-mass ratio, fast acceleration and rapid start-up, so most of the major modern ** use gas turbines. But its main disadvantage is that the efficiency is not high enough, the efficiency decreases quickly under partial load, and the fuel consumption is high when no-load, so the endurance and speed of a single gas turbine may not be as good as that of a steam turbine.

Diesel engine: Diesel engine has the significant advantages of high thermal efficiency and low energy loss, so it is an economical engine, which is preferred by civilian ships and used by military ships. However, the shortcomings of diesel engine, such as high pollution, high noise, large volume, and small power-to-mass ratio.

Therefore, the diesel engine generally cannot become the high-speed main engine of the ship, and the power of the modern diesel engine is not comparable to that of the gas turbine in the same volume.

It can be seen from this that the advantages and disadvantages of the above-mentioned ship engines, when there are different requirements for the ship, the main engine is different. For example, for a small speedboat, it is not suitable to install a large steam turbine; Another example is a heavy aircraft carrier, the installation of diesel engines with a small power-to-mass ratio cannot meet the requirements of high speed, and the power is insufficient; It is impossible for submarines to choose gas turbines (except for the AIP system in closed cycle mode), because gas turbines have a great demand for air flow, which is not suitable for submarines with closed hulls, and the fuel loss of gas turbines is high, which is unrealistic for submarines that pay attention to continuous activity, so modern conventional submarines mostly use diesel engines with better economy.

Through the above analysis, we can see the principle of diesel-fuel combined power, diesel-fuel combined power (CODOG), as the name suggests, is to install diesel engine and gas turbine at the same time, make full use of the advantages of both to overcome the shortcomings of both. For example, gas turbines with good acceleration, fast starting, and strong power are used for start-up and fast sailing, while diesel engines with good economy and high thermal efficiency are used for cruising and searching to achieve the optimal match.

Diesel ships, of course

Gas turbines generally burn natural gas, but they can also be replaced with fuel, such as gasoline and diesel. Large gas turbines for ships are the same.

Marine gas turbine is an important power plant on modern ships, which heats air through a compressor and then passes into the combustion chamber.

The fuel is burned in the combustion chamber to produce high-temperature gas, which then enters the turbine and impacts the blades on the turbine, making the turbine rotate at high speed and driving the propulsion engine to work. Gas turbines do not need to call for boilers, are lightweight, small in size, and have high power, and can be used as the main engine of large ships.

As we all know, gas turbine units are not an emerging power plant, but have been developed for decades.

It is an industrial force supported by a comprehensive discipline with deep technical accumulation. The first gas turbine was built by the Germans with.

Successfully developed in the forties of the last century, due to its good aerodynamic properties, it was subsequently obtained in large quantities in aviation.

Wide range of applications. The units developing surface ships were plagued by surface power plants and saw the suppression of aviation gas turbines.

After the future of slip and carry suppressed by technology, the modification of high-performance aero engines, the development of simple cycle technology, and intercooling.

The optimization of the complex cycle of heat recovery and the application of advanced waste heat utilization type combined cycle have made the gas turbine of military ships.

The development and application have entered a new era. However, due to economic interests and maintenance considerations, merchant ships have not been able to do so.

There is a large-scale popularization of gas turbines, and their proportion is very small. In recent years, countries and various maritime organizations have been motivated by the protection of the environment.

The sulfur oxide and nitrogen oxide emissions of diesel engines are strictly limited, and oil prices are rising.

The rise of the emerging middle class in a large number of emerging countries, the booming yacht business requires high speeds, making merchant ships.

gas turbine applications are becoming hot.

Gas turbines should be made of aviation kerosene, because of the high calorific value, ** cheaper than diesel.

Marine high-power gas turbines should be used from an economic point of view with light diesel oil (No. 0 diesel).

The fuel for military gas turbines can be natural gas, diesel, kerosene, and many more. China's natural gas reserves are low, and we must import a large amount of foreign countries if we can't fight a war, so the fuel for gas turbines is diesel.

Countries with high gas reserves like Russia, there is no doubt that gas turbines are fueled with natural gas. France with alcohol.

There are still very few gas turbines for civilian ships.

That's right. Modern steamships are powered by turbines and steam engines. With the development of science and technology, inland waterway shipping 50 years ago has already been huge.

The big change was that it was common for ships to sail at that time, with black smoke coming out of their long chimneys, which were produced by burning coal to produce water in their boilers.

Steam, which is then used by the steam engine to do the work, is used as the driving force to propel the ship forward. The weight of the steam engine device is too bulky and too bulky.

Large, depending on the amount of power required, some ships can use several boilers, each with a chimney. River boats.

The power of the ship has long been the use of marine diesel engines, which have high power, small site area, environmental protection and hygiene.

The first steamships benefited from Watt's refinement of the steam locomotive, which made it possible to power other machines. In modern times, the power of a ship** can be a turbine or a steam engine.

The Wright brothers invented the airplane after the invention of the internal combustion engine, so the power ** is the internal combustion engine. But the main power plant of modern aircraft is turbine and piston engines.

Roughly correct. Because the new direction is clean energy, such as wind power, solar energy, etc.

I know that civilian ships must be powered by diesel engines, and many engine factories now have marine engines. There may be very little gas, and the most obvious thing about using gas is that the power is insufficient and the reserve is inconvenient. I don't know much about nuclear power, but I've seen that now ships powered by nuclear power are being rebuilt.

Diesel engines are the mainstream, gas turbines are mostly used in the new generation of large ships, and nuclear power is mainly used on large aircraft carriers, cruisers and nuclear submarines.

There are diesel engines, steam, and nuclear power is very precious and is not used by relatives.

Small ships with gas turbines and diesel engines, large marine steam turbines and gas turbines, diesel engines can only make the best to run at low speed, fuel saving, gas turbines are very fuel-intensive, but the thrust is large, the steam turbine needs to be preheated, the start is very slow, the cost of nuclear power maintenance is huge, the maintenance time is huge, the small ship is not practical at all, like the Nimitz-class aircraft carrier of the United States one-third of the time in service in maintenance, and it took 2 billion to dismantle the reactor when it was decommissioned.

For example, China's 052C, which alternates with diesel fueling, uses two German diesel engines when sailing at low speeds, and two DA DN80 gas turbines at full speed, which can reach 29 knots, which is very fuel-efficient.

The Burke class in the United States uses 4 LM2500s, and gas turbines are also used at low speeds, which is too fuel-intensive.

Steam turbine and gas turbine, working principle, prime mover is mainly divided into electric motor, steam engine, internal combustion engine and steam turbine, etc. A steam turbine is a steam turbine, whereas a gas turbine is an internal combustion engine. In general, the thermal efficiency of an internal combustion engine is higher than that of a steam turbine.

The following principles are briefly explained.

1.Steam turbines.

It mainly includes three parts: boiler, steam turbine and condenser, which is briefly described as the fuel burned in the boiler combustion chamber to turn the water in the boiler into water vapor at a certain pressure and temperature. The steam enters the steam turbine through the pipe, and the expansion work pushes the steam turbine to rotate. The steam turbine drives the propeller to propel the ship.

The steam after the work is returned to the condenser, where it is cooled into water and then sent back to the boiler for the next cycle. As shown in the figure below, the direction of the arrow is the direction of the soda circulation.

2.Gas turbine.

There are also three parts, the compressor, the combustion chamber and the gas turbine. The simplest gas turbine is the marquee, you can observe the air from the air inlet into the gas turbine, the high-speed rotating compressor compresses the air into high-pressure air and sends it into the combustion chamber, the fuel is burned in the combustion chamber, generating high-temperature and high-pressure air, and the high-temperature and high-pressure air expands in the turbine to do work to promote the turbine to do work.

Advantages and disadvantages (compared to diesel engines).

1.Steam turbines.

Advantages: 1) High power of single machine.

2) The steam turbine is a high-speed spinning machine, with less vibration and noise.

3) The work is stable and the friction part is less, so the reliability is high and the life is long.

4) Anyway, it is burned for heating, the fuel requirements are low, and inferior coal and oil can be used.

Disadvantages: 1) The energy conversion process is long and complex, so the thermal efficiency is low, the fuel consumption is high, and the economy is poor.

2) The steam turbine has a high speed and cannot be directly reversed, so it must be equipped with a reduction gear with a large reduction ratio and a reversing gearbox when using the ship, which will reduce the transmission efficiency.

3) It takes a long time for the boiler to produce steam from the cold state, and the maneuverability is poor.

4) The device is multi-equipment, complex, and the overall weight and scale are large.

2.Gas turbine.

Advantages: 1) Very high power-to-weight ratio, that is, under the same power, the weight is the smallest, and when the same weight, the power is the highest.

2) Less vibration and noise.

3) Low working pressure.

4) Sufficient combustion, less CO and hydrocarbon loss.

Disadvantages: 1) Expensive, high-speed and high-temperature environment has very high requirements for manufacturing materials and processes.

2) It is also expensive to use and has high fuel consumption. The thermal efficiency is higher than that of a steam turbine, but it is still much lower than that of a diesel engine. Especially in the case of idling, fuel consumption is very high. The GT25000 used in the 052 series has a thermal efficiency of 38%, and the diesel engine is more than 50%.

3) When the power is changed, the response is slower than that of the diesel engine, that is, the acceleration and deceleration response is slow. It is also not possible to reverse. Gas turbines are best used to work in stable working conditions, and the speed change is very slow, so it is difficult to use this thing in cars.

4) Short life (or expensive).

The difference between a gas turbine and a steam turbine is **1. Components. In gas turbines, compressors, combustion chambers, and power turbines are important components.

In steam turbines, steam boilers and accessories are important components.

2. Start. Gas turbine start-up is simple and fast.

The start of a steam turbine is not easy and takes a long time.

3. Efficiency. Gas turbines have low efficiency lines.

Steam turbines are highly efficient.

4. Internal temperature.

In a gas turbine, the internal temperature reaches 1500 degrees Celsius, which is much higher than that of a steam turbine.

In a steam turbine, the internal temperature only reaches 500 to 650 degrees Celsius, less than half the reaction temperature of a gas turbine.

5. Installation space.

In gas turbines, less installation space is required.

6. Large-scale production.

Gas turbines produced per kilowatt have less mass.

The quality of the steam turbine per kilowatt produced is higher.

7. Cost. Gas turbines have low installation and operating costs.

Steam turbines require high installation and operating costs.

8. Control. In gas turbines, control is easy as load conditions change.

In steam turbines, control is difficult as load conditions change.

9. Dependence on water supply.

Gas turbines do not depend on water supply.

The steam turbine depends on the water supply.

10. Execution.

Gas turbine engines perform the entire Brayton cycle.

A steam turbine is just a component that performs one step of the rankine cycle.

11. Working fluid.

Gas turbines use air or other gases as the working fluid.

Steam turbines use high-pressure steam as the working fluid.

Gas turbine. <>

Steam turbines.

The power generation device is divided into two parts: the power generation part and the power part, the general power generation part is similar, both are coils cutting magnetic inductance lines, the cutting movement is rotary motion, and the power part is different, this is the fundamental difference you have to ask.

1. Internal combustion engine: It is the same as a car, the fuel is burned in the cylinder, the piston is pushed after the gas expands, and the piston is transmitted to the crankshaft through the crank cam mechanism, and the crankshaft does a rotary movement, which can drive the power generation part.

2. Steam turbine: The superheated steam enters the steam turbine and acts on the rotor through the nozzle formed by the dynamic and static blade grid, that is, the pressure energy and heat energy are converted into mechanical energy, so that the rotor rotates and moves, which can also drive the power generation part.

3. The gas turbine has not been contacted, and it should be the same as the previous two, :)