Analysis of a high-pressure multistage axial compressor at off-design conditions with coarse Large Eddy Simulations

Abstract

This paper aims at evaluating Large Eddy Simulations (LES) for the prediction of the performance line and flow at off-design conditions in a multistage high-pressure compres-sor. A coarse and an intermediate grid are specifically investigated, since their associated computational cost appears affordable in an industrial context. Several operating condi-tions of the 3.5 stages high-pressure compressor CREATE are simulated, then results are compared to experimental data and to an existing URANS simulation. Both grids yield iso-speed performance lines close to experimental measurements, but only the intermedi-ate one is able to correctly predict the experimental point at lowest mass flow rate. The unstable regime is specifically investigated in the last stage of the intermediate grid, show-ing the presence of rotating instabilities. Their amount and spinning velocity are similar to experimental observations and previous URANS results. Hence coarse LES appears as an interesting tradeoff for off-design predictions of flow in a multistage compressor.