China tests world’s most powerful Stirling engine for submarine propulsion
China’s Global Times reported on Wednesday that a research institute in the country had developed a new heat engine, which it described as the most powerful type of its kind in the world.
The report claimed that the 711 Research Institute of the China State Shipbuilding Corporation (CSSC) had developed the new âStirlingâ engine.
What is a Stirling engine?
A Stirling engine is a “closed cycle” engine; that is to say that the propellant it contains is not ejected, but circulates continuously. This is different from “open cycle” engines, such as those used in cars, in which the propellant is burnt and ejected.
A Stirling engine converts heat into mechanical energy by the movement of two or more pistons inside the cylinders. According to Interesting Engineering, âThe gas inside a Stirling engine never leaves the engine. They are heated and cooled over and over again, so that they are never released in the form of an explosive exhaust. This regenerative engine has the ability to use the same gas over and over to generate electricity; therefore, a Stirling engine can prove to be much more efficient than the internal combustion engine used in modern vehicles. The heat for the engine is supplied by an external source, such as fossil fuels (gasoline or coal), nuclear energy, solar energy or the heat of decaying plants.
Robert Stirling, a Scottish clergyman and engineer, built the first engine of this type in 1816 and patented it. The engine was created for the purpose of competing with the steam engine. In the early 1800s, the steam engine was the most powerful form of propulsion available, but it was prone to the threat of explosions. The Stirling engine minimized the risk of explosion.
However, the ability of the Stirling engine to change its power output is limited compared to open cycle engines. Thus, the adoption of Stirling engines has been less.
Use in submarines
Since they lack explosive exhaust and have less vibration, Stirling engines are inherently quieter. This makes them useful for purposes where quiet operation is critical.