Confirming Centrifugal Compressor Aerodynamic Performance Using Limited Test Data Combined With Computational Fluid Dynamic Techniques.

Abstract

Facing increased market demands for improved aerodynamic efficiency, centrifugal compressor manufacturers must be able to predict and quote the best performance available from the machinery they produce. Confidence in these predictions allows manufacturers to remain competitive while avoiding the possibility of penalties for performance not achieved and, what is most important, retain customer confidence for machinery produced. Results from hardware and model testing are used to calibrate proprietary aerodynamic selection and sizing software. The challenge presented herein involves the measurement and prediction of impeller aerodynamic performance for a singlestage centrifugal compressor for which accurate test data is very difficult to obtain. The impeller under consideration was modelled using a commercially available computational fluid dynamics (CFD) analysis code developed by a Canadian company. The measured impeller's total and static discharge pressures were compared to the CFD code's predictions and found to be in excellent agreement. However, temperature rise data across the stage proved difficult to accurately measure. Without the benefit of reliable data to calculate aerodynamic efficiency, the CFD code was used to predict the impeller's efficiency. The results of the code proved to be very close to the values for efficiency originally predicted in the design of the stage.