Variable geometry compressor

• Main Author: Cao, Wei
• Other Authors: Alessandro Romagnoli
• Format: Final Year Project
• Language: English
• Published: 2016
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/68239
• Institution: Nanyang Technological University

With growing industrial demands for smaller engines of higher specific power, there is an increased urgency to develop novel ideas which can provide incremental improvements to existing compressor technologies. Surge remains a critical constraint in compressor operation, restricting performance and cost. This project aims to investigate the effectiveness of an air injection method to realise potential enhancements in centrifugal compressor performance. A Computational Fluid Dynamics (CFD) simulation framework was established to model centrifugal compressor flow. A mesh of 448810 elements and 420288 nodes was generated in ICEM CFD. Adequate numerical accuracy was attained while conserving computational resources. Steady state simulations were conducted in ANSYS CFX to yield the baseline compressor characteristic curves. These were validated with existing experimental data. Subsequently, an additional air injection surface was introduced. A parametric study was conducted to investigate the effects of pitch angle, yaw angle and injection mass flow rate on compressor performance. At medium to high flow rates, a smaller pitch angle of 25° and higher injection mass flow of 6% yielded marginally better compressor performance. In contrast, yaw angles of 7.5° and 15° achieved similar results. It was also concluded that regardless of the injection settings, the air injection technique tested had no apparent impact in suppressing compressor surge.