CFD SIMULATION OF BLADE LOAD DISTRIBUTION CONTROL AS ACTIVE CENTRIFUGAL COMPRESSOR SURGE SUPPRESSION

Abstract

Turbomachines necessitates up-to-date methods to ensure economical and safe operation at the same time with the widest possible range that makes novel ideas inevitable to handle classical problems. The most dangerous instability in compression systems is surge that has to be suppressed before its onset to avoid structural damages or other different adverse consequences in the system. As surge occurs at low delivered mass flow rates the conventional widely spread surge control is based on bypassing or recycling the unnecessary airflow. This method is used on a large number of gas turbines and provides a robust control on suppressing compressor surge while its efficiency loss is significant. The aim of this paper is to show the results of CFD simulations of an active surge suppression concept using flow injection at a mid-span location rather than at the inlet. This injection leads to a different blade load distribution along its chord resulting in a possible effect of suppress instabilities. Its advantage over concurrent methods is that it can be based on up-to-date MEMS technology leading to moderate losses but comparable stability enhancement. Previously the one-dimensional mathematical model of the concept has been established, but it is inevitable – as a virtual prototyping – to carry out detailed numerical simulation of the device. The paper shows the results of this CFD simulation.