At the end of 19, Laval in Sweden and Parsons in Britain built practical steam turbines respectively. Laval built the first 5 HP (3.67 kW) single-stage impulse turbine in 1882, which solved the problems related to nozzle design and strength design. Single-stage impulse turbine has little power and is rarely used now.
At the beginning of the 20th century, France Lato and Switzerland Zolai made multi-stage impulse steam turbines respectively. Multi-stage structure has opened the way for improving steam turbine power, and has been widely used, and the unit power is also increasing. Parsons obtained the British patent in 1884, and manufactured the first 10 horsepower multistage reactive steam turbine, which was in a leading position in power and efficiency at that time.
At the beginning of the 20th century, Curtis made a multi-speed steam turbine, and each speed stage generally had two rows of moving blades. After the first row of moving blades, guide blades are installed on the cylinder to guide the steam flow to the second row of moving blades. At present, speed-class steam turbines are only used for small steam turbines, mainly driving pumps and blowers. , often used as the first stage of small and medium-sized multistage steam turbines.
Compared with the reciprocating steam engine, the steam flow in the steam turbine is continuous and high-speed, and the flow rate per unit area is large, so it can generate more power. High-power steam turbines can use higher steam pressure and temperature, so the thermal efficiency is higher. /kloc-since the 20th century, the development of steam turbines has been to increase the single unit power and improve the thermal economy of the unit on the basis of continuously improving safety, reliability and durability and ensuring convenient operation.
The appearance of steam turbine promoted the development of electric power industry. By the beginning of the 20th century, the power of a single steam turbine in power station had reached 10 MW. With the increasing application of electric power, the peak load of power stations in new york and other big cities in the 1920s approached 65,438+000 MW. If the power of a single machine is only 10 MW, it is necessary to install nearly 100 units. Therefore, in the 1920s, the unit power was increased to 60 MW, and in the early 1930s, 1.65 MW and 208 MW steam turbines appeared.
Since then, the economic recession and the outbreak during the Second World War have made the increase of single turbine power stagnate. In 1950s, with the post-war economic development, the demand for electricity increased by leaps and bounds, and the single unit power began to increase continuously, and large steam turbines of 325-600 MW appeared one after another. In 1960s, a 1000 MW steam turbine was built. A 1300 MW steam turbine was built in 1970s. At present, the single machine power widely used in many countries is 300 ~ 600 MW.