Experimental and Numerical Investigation of Different Rectangular Volute Geometries for Large Radial Compressors

Abstract

Increases on mass flow rates of modern radial process compressors result on larger machine components. In particular, the dimensions of the outlet volutes increase strongly, resulting in disproportionately large machines whose technical feasibility is restricted due to technological and economical reasons. A resulting aim is to design modern radial compressors much more compact, while improving the efficiency and the pressure ratio. Therefore, the present experimental investigation addresses the compressor behaviour for reduced dimensions of rectangular volutes. Furthermore, the experimental setups are numerically modelled and different operating points are simulated with a commercial CFD-Code. A rectangular, external reference volute is equipped with differently shaped blockage-inlays and the global compressor parameters are measured for all variants. Additionally, the pressure and velocity distributions of the local flow field are determined experimentally for varying mass flow ratios at different circumferentially distributed volute layers. The decrease of the volute cross-section results in a reduction of the compressor map width especially at high mass flow rates. Recommendations are given for designing compact volutes of large radial compressors.

Effect of housing size on the performance of a centrifugal compressor for turbocharger application: An experimental and numerical study

“…Also, more reduction in compressor efficiency occurs with the SD20 housing for NC operating point at 0.87 N speed. The trend of efficiency drop with smaller volute was also reported by Bartelt et al 9 The test data of SD20 housing at NC point with 1.13 N show marginally less efficiency drop as compared to other speeds. This trend might be because of reduced flow recirculation and pressure losses with higher flow velocity.…”

“…But, the larger volute showed a higher-pressure ratio and efficiency at the near-choke flow conditions, together with some efficiency drops at the near-surge point. Likewise, the experimental and numerical studies by Bartelt et al 9 on a rectangular volute with reduced area showed reduced pressure ratio and efficiency at higher mass flow rates but with an improved volute flow behaviour at the near-surge point. Also, Fischer and Seume 10 conducted CFD analysis with different volute sizing parameters (ratio of volute throat area and diffuser outlet area) to optimize the design for a compact compressor housing.…”

Experimental and numerical flow field investigation through two types of radial flow compressor volutes

“…Five-hole probe is used to measure the velocity and pressure fields to verify the numerical CFD code at some operating points [8].…”