Steam turbine, also known as steam turbine engine, is a rotary prime mover that uses steam as power to convert the thermal energy of steam into mechanical work. This equipment is widely used in the field of energy conversion, especially in large thermal power plants and ship power systems.
The working principle of steam turbine is quite exquisite. Steam with a certain pressure and temperature enters the steam turbine, first passes through the nozzle and expands in it, thereby obtaining a very high speed. The high-speed steam then flows through the moving blades on the turbine rotor, and the moving blades are impacted by the steam and rotate, thereby driving the turbine rotor to rotate at a certain speed. When the moving blades are reactionary, the steam continues to expand in the moving blades, and the reaction force generated also makes the moving blades do work. In this process, the thermal energy of the steam is effectively converted into mechanical energy.
The structure of the steam turbine is relatively complex, usually consisting of a rotating part (rotor) and a stationary part (stationary body or stator). The rotating part includes rotating parts such as moving blades, impellers (drums for reactionary steam turbines), main shafts, couplings and fasteners. The stationary part includes the cylinder, steam chamber, nozzle, partition, partition sleeve (the reaction turbine is the stationary blade holding ring), steam seal, bearing, bearing seat, machine base, sliding pin system and related fastening parts.
The development history of steam turbine can be traced back to ancient times, but the real steam turbine technology has gradually developed in modern times. In the 1st century AD, Hero of Alexandria recorded a steam-rotating ball that rotates by steam reaction force, which is considered to be the earliest prototype of the reaction steam turbine. In 1882, C.G.P.de Laval of Sweden made the first 5 horsepower (3.67 kilowatt) single-stage impulse steam turbine, which marked the official birth of steam turbine technology. With the continuous advancement of technology, steam turbines have gradually developed into an indispensable and important equipment in modern industry.
Steam turbines play an important role in many fields. In the field of electricity, steam turbines are one of the main equipment of large thermal power plants. Steam turbines can achieve efficient and stable power output by providing steam to drive power generation through large-scale coal-fired, oil-fired and other boilers. In the field of ships, steam turbines were once the main power source for large merchant ships and warships. Although there has been a trend of being replaced by other power sources in recent years, there is still a certain scope of application in certain specific fields.
Steam turbines have many advantages. For example, the single-unit power is large, reaching more than 70,000 kW, which is suitable for large ships and fast and high-power ships; it works smoothly, with less vibration, noise and wear, and is easy to repair and maintain; it can use cheap and low-quality fuels, and consumes very little lubricating oil. However, steam turbines also have some disadvantages, such as long start-up time, many auxiliary equipment, complex devices, large heat loss, and low thermal efficiency.
With the in-depth practice of the global "dual carbon" goal, the steam turbine industry is also actively exploring low-carbon or even zero-carbon technical paths. The efficiency of steam turbines has been continuously improved by optimizing structural design, improving manufacturing precision and adopting advanced cooling technology. At the same time, the combined use of steam turbines and other energy conversion equipment such as gas turbines has further improved the efficiency and reliability of the entire energy system.
In short, as a rotating master of heat energy conversion, steam turbines play an important role in the field of energy conversion. With the continuous advancement of technology and the continuous expansion of the market, the steam turbine industry will usher in a broader development prospect.
