3rd Class Power Engineer (3B2) 2025 – 400 Free Practice Questions to Pass the Exam

Adjustable inlet diffuser vanes on centrifugal air compressors are designed to influence the compressor's performance and operating characteristics. By altering the angle of the vanes, the flow of air entering the compressor can be modified, impacting parameters such as pressure ratio, flow rate, and efficiency. This adaptability allows for improved performance under varying load conditions, helping to maintain optimal operation across a range of demands.

While some other options consider air management, they do not specifically address the primary function of these vanes. For instance, changing the direction of airflow to remove moisture pertains more to specialized systems rather than the fundamental role of the inlet vanes in a centrifugal compressor. Similarly, the removal of foreign particles is typically handled by filtration systems, not by the adjustment of inlet vanes. While reducing the amount of air entering the compressor may seem relevant, the primary intent of the vanes is to enhance overall operational flexibility rather than solely restricting air quantity. Thus, the correct function of adjustable inlet diffuser vanes is to change the operating characteristics of the compressor for optimized performance.