Understanding the Compressor Section of Aircraft Gas Turbine
The aircraft gas turbine engine has highly advanced our capabilities of flight, allowing for aircraft to conduct powerful compression and combustion to achieve high altitude flight at great speeds. As the compression of air is crucial for efficient flight operations, the compressor section of the engine assembly is specifically designed to handle high amounts of intake air and increase its pressure. With the compressor, air can be pressurized to benefit fuel ignition, cabin pressurization, de-icing, cabin heating and cooling, and many other processes that benefit flight operations. Due to the various roles undertaken by the compressor, it is paramount that such assemblies are understood and well-maintained to sustain their efficient operations.
Across aircraft utilizing gas turbine aircraft engines, the two main compressor types include those that are centrifugal and axial flow. While some components are shared between the two types, varying characteristics and functionalities set them apart. With centrifugal-flow compressors, an impeller, diffuser, and compressor manifold serve as the primary components of the assembly. For its functionality, the centrifugal-flow compressor utilizes incoming air from the inlet duct and rapidly accelerates it outward through the use of centrifugal action. The impeller is often created as a single forging, and it is responsible for speeding up air and sending it outward towards the diffuser. With moving air exhibiting a velocity near the speed of sound, the diffuser then transforms the kinetic energy of air into high amounts of pressure by diffusing velocity. Depending on the assembly, diffusers may be with or without vanes, or may have an alternating combination. As the air moves from the diffuser, it then enters a large empty chamber known as a collector or plenum.
With the axial flow compressor, the rotor and stator serve as the primary components of the assembly. For the rotor, blades are placed on a spindle, and such compressor blades are used to impel air in a fashion similar to propellers due to their angle. With the rotor, air is taken in at the compressor inlet duct and forced through various stages. At each stage of the compressor, air is compressed at a ratio of 1.25:1. With the rotor consistently increasing the speed of air, compression increases as energy is induced. With stator blades serving as diffusers, the air is then slowed down as velocity and transformed into pressure. Depending on the aircraft gas turbine engine and its need for total pressure, the rows of blades may be changed to affect the amount of compression achievable.
Based on the aircraft in question and its particular characteristics and requirements, the centrifugal-flow and axial-flow type each provide their own advantages and disadvantages that make them more beneficial for specific applications. With the centrifugal compressor type, high amounts of pressure can be achieved at each stage, and high efficiency is attainable over a wide range of rotational speeds. Furthermore, the low weight, starting power requirements, and costs associated with centrifugal-flow compressors make them very beneficial for certain aircraft types. Despite this, centrifugal-flow compressors feature large frontal sections for the airflow that they draw in, and there are losses due to turns between stages.
Axial-flow compressors, on the other hand, are advantageous due to their small frontal sections that are still able to bring in air for compression. With high peak efficiencies, high ram efficiencies, and increased pressure rises, air can be thoroughly compressed for combustion with little losses throughout each stage. Nevertheless, the axial-flow type does suffer from other factors such as high costs from the difficulty of manufacturing, high weight as compared to the centrifugal type, and high starting power requirements. Furthermore, the efficiency advantages provided by the axial-flow compressor are often only achievable in slim rotational speed ranges.
Through the use of a compressor and its various internal components, the combustion chamber and other aircraft systems can efficiently receive pressurized air for conducting various procedures and operations. At ASAP AM Spares, we serve as a leading supplier for all types of compressors and other aviation hardware parts that can serve your operational requirements. As you explore our expansive part and manufacturer catalogs on our website, you may request a quote on items that you are interested in at any time through the submission of an Instant RFQ form. Once received by our staff, they will review your request and reach out to you in 15 minutes or less to continue the purchasing process.