59879 - Flow Field Analysis and Optimization of a Centrifugal Compressor Volute 

Turbocharging has become a fundamental technology to realize engine downsizing, which is an attractive strategy for low carbon vehicles in the near term. The stable operation of turbocharger compressor at low and high flow rates is crucial to provide peak torque demand and rated power for turbocharged automotive engines.

The scroll or volute is a key component in centrifugal compressors, its design not only impacts the compressor efficiency but also affects the operating range. This component causes a distorted pressure field upstream which can contribute to stall on the impeller, inducing surge. As the flow inside the volute is fully three dimensional and turbulent, a better understanding of flow mechanism is key to enable a volute design methodology.

In this study a centrifugal compressor volute has been studied numerically and validated experimentally in order to identify the parameters that contribute to the main flow losses. By solving Reynolds average Navier-stokes (RANS) equations with k-Epsilon turbulence model, the three-dimensional flow field model of the compressor was obtained using a commercial code. Base on this analysis, an optimized compressor volute is presented. The results show that the total to total isentropic efficiency and surge margin are improved by 1.5% and 4.5% at 196,486 rpm with the new design, both are confirmed by experiments. The flow field inside the new volute is also captured and compared to the numerical analysis carried out from the original.