What is the function of the expansion turbine in an air-cycle cooling system?

In an air-cycle cooling system, the expansion turbine plays a crucial role by extracting energy from the incoming compressed air and simultaneously reducing its pressure. This process is a part of the cooling cycle, which relies on the principles of thermodynamics. As the pressurized air enters the turbine, it expands, and during this expansion, the air loses energy, which leads to a drop in temperature. This allows the air to cool effectively before being circulated back into the cabin or used for other purposes in the aircraft.

The cooling effect achieved by the expansion turbine is essential for providing a comfortable environment in the aircraft. The ability to cool the air efficiently is fundamental to the operation of air-cycle cooling systems, making the extraction of energy and reduction of pressure an integral function of the expansion turbine. Other options, such as compressing incoming air, heating the air, or filtering contaminants, do not directly relate to the primary function of the expansion turbine in this context.