Effects of Manufacturing Noise on Microturbine Centrifugal Compressor Impeller Performance

This paper presents a study on a small centrifugal impeller for microturbine application from a manufacturing perspective. The aim is to analyze the impact of geometric deviations on part performance using adequate performance modeling tools and statistical methods. A one-dimensional (1D) performance analysis tool has been developed in-house derived from the meanline and two-zone modeling methods. The 1D model has proved to be a simple and computationally inexpensive tool for having a quick performance analysis of the impeller using basic geometric information extracted from part drawings. For the sensitivity analysis, a total of eight input geometric parameters including radii, tip-clearance and blade angles have been varied individually within specific limits in the 1D tool for classifying their influence on the output performance. Since the 1D model is a simplified version of a much complex three-dimensional (3D) model, a commercial computational fluid dynamics (CFD) tool has been used to provide a comparison with the 1D model and scrutinize the effects of such deviations on the fluid behavior inside the impeller passage at a detailed level. For uncertainty quantification, Monte Carlo simulation has been performed using the 1D model to assess the variability of overall impeller output performance to simultaneous random deviations in the input geometric parameters. The study is useful to evaluate the possibility of designing gas turbine parts for manufacturability and superior production cost-effectiveness.